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//! This crate provide generic cartesian product iterator, //! combination iterator, and permutation iterator. //! //! # Three main functionalities //! - Cartesian product //! - Combination //! - Permutation //! //! # Two different style on every functionality //! This crate provide two implementation style //! - Iterator style //! - Callback function style //! //! # Easily share result //! - Every functionalities can take Rc<RefCell<>> to store result. //! - An iterator that return owned value. //! - Every callback style function can take Arc<RwLock<>> to store result. //! //! # Easy usage //! Three built-in traits that add cart_prod, combination, and permutation functionality //! to slice/array, Rc<RefCell<&mut[T]>>, and more. //! //! # Unreach raw performance with unsafe //! Every functionalities can take raw mutable pointer to store result. //! //! # Example //! - Getting k-permutation where k is 3 and n is 5. //! ``` //! use permutator::{Combination, Permutation}; //! let mut data = &[1, 2, 3, 4, 5]; //! let mut counter = 1; //! data.combination(3).for_each(|mut c| { //! c.permutation().for_each(|p| { //! println!("k-permutation@{}={:?}", counter, p); //! counter += 1; //! }); //! }); //! ``` //! - Getting lexicographically ordered k-permutation where k is 3 and n is 5. //! ``` //! use permutator::{Combination, XPermutationIterator}; //! let mut data = &[1, 2, 3, 4, 5]; //! let mut counter = 1; //! data.combination(3).for_each(|mut c| { //! XPermutationIterator::new(&c, |_| true).for_each(|p| { //! println!("k-permutation@{}={:?}", counter, p); //! counter += 1; //! }); //! }); //! ``` //! - Cartesian product of set of 3, 4, and 5 respectively //! ``` //! use permutator::{CartesianProductIterator, cartesian_product}; //! let mut domains : &[&[i32]]= &[&[1, 2], &[3, 4, 5], &[6, 7, 8, 9]]; //! println!("=== Cartesian product iterative style ==="); //! CartesianProductIterator::new(domains).into_iter().for_each(|p| { //! println!("{:?}", p); //! }); //! println!("=== cartesian product callback style ==="); //! cartesian_product(domains, |p| { //! // `p` is borrowed a ref to internal variable inside cartesian_product function. //! println!("{:?}", p); //! }); //! ``` //! - Easy sharable result //! ``` //! use std::cell::RefCell; //! use std::rc::Rc; //! use std::time::Instant; //! use permutator::CartesianProduct; //! //! let mut counter = 0; //! let timer = Instant::now(); //! let data : &[&[u8]]= &[&[1, 2], &[3, 4, 5, 6], &[7, 8, 9]]; //! let mut result = vec![&data[0][0]; data.len()]; //! let shared = Rc::new(RefCell::new(result.as_mut_slice())); //! //! (data, Rc::clone(&shared)).cart_prod().for_each(|_| { //! println!("{:?}", &*shared.borrow()); //! // and notify result borrower(s) that new product is available. //! //! counter += 1; //! }); //! //! println!("Total {} products done in {:?}", counter, timer.elapsed()); //! ``` //! - Unsafely share result example //! ``` //! use std::time::Instant; //! use permutator::Permutation; //! //! let data : &[i32] = &[1, 2, 3, 4, 5]; //! let mut counter = 0; //! let k = 3; //! let mut result : Vec<&i32> = vec![&data[0]; k]; //! // `result` can be share safely anywhere //! let shared = result.as_mut_slice() as *mut [&i32]; //! // `shared` can be share as long as `result` is alive //! let timer = Instant::now(); //! // unsafe statement may be omit because the permutation trait //! // hid it internally. However, keep in mind that it rely //! // on a pointer so every operation is still considered unsafe. //! unsafe { //! (data, k, shared).permutation().for_each(|_| { //! println!("{:?}", &*shared); //! // and notify result borrower(s) that new permutation is available. //! //! counter += 1; //! }); //! //! println!("Total {} combination done in {:?}", counter, timer.elapsed()); //! } //! ``` //! # See //! - [Github repository for more examples](https://github.com/NattapongSiri/permutator) //! //! # Found a bug ? //! Open issue at [Github](https://github.com/NattapongSiri/permutator) extern crate num; use num::{PrimInt, Unsigned}; use std::cell::RefCell; use std::collections::{VecDeque}; use std::iter::{Chain, ExactSizeIterator, Iterator, Product, Once, once}; use std::rc::Rc; use std::sync::{Arc, RwLock}; pub mod copy; /// Calculate all possible cartesian combination size. /// It is always equals to size.pow(degree). /// # Parameters /// - `size` is a size of data to generate a cartesian product /// - `degree` is a number of combination of data. /// # Examples /// ``` /// use permutator::get_cartesian_size; /// /// get_cartesian_size(3, 2); // return 9. /// get_cartesian_size(3, 3); // return 27. /// ``` /// # See /// [get_cartesian_for](fn.get_cartesian_for.html) pub fn get_cartesian_size(size: usize, degree: usize) -> usize { size.pow(degree as u32) } /// Get a cartesian product at specific location. /// If `objects` is [1, 2, 3] and degree is 2 then /// all possible result is [1, 1], [1, 2], [1, 3], /// [2, 1], [2, 2], [2, 3], [3, 1], [3, 2], [3, 3] /// /// # Parameters /// - `objects` is a slice of an object. /// - `degree` is a degree of cartesian size. /// - `i` is a specific location to get a combination. /// /// # Examples /// ``` /// use permutator::get_cartesian_for; /// /// let nums = [1, 2, 3]; /// get_cartesian_for(&nums, 2, 0); // Return Ok([1, 1]) /// get_cartesian_for(&nums, 2, 3); // Return Ok([2, 1]) /// get_cartesian_for(&nums, 2, 8); // Return Ok([3, 3]) /// get_cartesian_for(&nums, 2, 9); // Return Err("Parameter `i` is out of bound") /// get_cartesian_for(&nums, 4, 0); // Return Err("Parameter `degree` cannot be larger than size of objects") /// ``` pub fn get_cartesian_for<T>(objects: &[T], degree: usize, i: usize) -> Result<Vec<&T>, &str> { if i >= get_cartesian_size(objects.len(), degree) { return Err("Parameter `i` is out of bound") } if objects.len() < degree { return Err("Parameter `degree` cannot be larger than size of objects") } let w_len = objects.len(); let mut result = VecDeque::new(); let mut idx = i; (0..degree).for_each(|_| { let x = idx % w_len; result.push_front(&objects[x]); idx /= w_len; }); return Ok(Vec::from(result)) } /// Calculate all possible number of permutation. /// It's equals to size!/(size - 1). /// /// # Parameters /// - `size` a size of data set to generate a permutation. /// - `degree` number of data set repetition. /// /// # Examples /// ``` /// use permutator::get_permutation_size; /// /// get_permutation_size(3, 2); // return = 6 /// get_permutation_size(4, 2); // return = 12 /// ``` /// /// # See /// [get_permutation_for](fn.get_permutation_for.html) pub fn get_permutation_size(size: usize, degree: usize) -> usize { divide_factorial(size, size - degree) } /// Get permutation at specific location. /// If `objects` is [1, 2, 3, 4] and `degree` is 2 then /// all possible permutation will be [1, 2], [1, 3], /// [1, 4], [2, 1], [2, 3], [2, 4], [3, 1], [3, 2], /// [3, 4], [4, 1], [4, 2], [4, 3]. /// /// # Parameters /// - `objects` a set of data that is a based for permutation. /// - `degree` number of element per each location. /// - `x` is a location to get a permutation /// /// # Examples /// ``` /// use permutator::get_permutation_for; /// /// let nums = [1, 2, 3, 4]; /// get_permutation_for(&nums, 2, 0); // return Result([1, 2]) /// get_permutation_for(&nums, 3, 0); // return Result([1, 2, 3]) /// get_permutation_for(&nums, 2, 5); // return Result([2, 4]) /// get_permutation_for(&nums, 2, 11); // return Result([4, 3]) /// get_permutation_for(&nums, 2, 12); // return Err("parameter x is outside a possible length") /// get_permutation_for(&nums, 5, 0); // return Err("Insufficient number of object in parameters objects for given parameter degree") /// ``` pub fn get_permutation_for<T>(objects: &[T], degree: usize, x: usize) -> Result<Vec<&T>, &str> { let mut next_x = x; // hold ordered result for purpose of calculating slot let mut states = Vec::<usize>::with_capacity(degree); // a slot available for next result to check if it fit in. let mut slots = vec!(0; degree); // actual result to return to caller. let mut result = Vec::new(); if objects.len() < degree { return Err("Insufficient number of object in parameters objects for given parameter degree") } if x >= divide_factorial(objects.len(), objects.len() - degree) { return Err("parameter x is outside a possible length"); } for i in 1..degree + 1 { let div = divide_factorial(objects.len() - i, objects.len() - degree); // raw index that need to be adjusted before adding to result. let mut idx = next_x / div; // update x for next set of value calculation. next_x = next_x % div; if i > 1 { let mut counter = idx; // hold slot allocation simulation for (j, slot) in slots.iter().enumerate() { if counter < *slot { // found slot that can fit the value idx += j; // offset value for all previous slot(s) result.push(&objects[idx]); break; } else { counter -= slot; // take all the slot } } if result.len() < i { // no slot found, appending to result idx = idx + i - 1; // offset for all previous slot(s) result.push(&objects[idx]); } let mut insert_point = None; // Find where the last value were inserted if result is in ordered. for j in 0..states.len() { if idx < states[j] { // found place to insert value insert_point = Some(j); break; } } if let Some(j) = insert_point { // insert value at insertion point states.insert(j, idx); } else { // the value is larger than entire result. states.push(idx); // append value to state as largest one. } slots[0] = states[0]; // update first state for j in 1..slots.len() { // update slot info if j < states.len() { // found slot required an update // slot size is equals to current state - previous state - 1. slots[j] = states[j] - states[j - 1] - 1; } else { // all slots with associated state updated break; } } } else { // First element. result.push(&objects[idx]); states.push(idx); slots[0] = idx - 0; } } Ok(result) } /// Core algorithm to generate cartesian product. /// # Parameters /// - `n` - the size of domains. /// For product on self, it equals to how many time to create product on self. /// - `set_len` - the closure to get length of each domain. /// - `assign_res` - the closure to store product into result /// - `cb` - the closure to get call on each generated product. /// # Execution sequence of closure. /// Each step in sequence is performed sequentially. /// It won't advance if the closure in given step isn't return. /// 1. `assign_res` once /// 2. `cb` once /// 3. `set_len` multiple times until it found at least a domain /// that doesn't exhausted, otherwise, terminate function. /// 4. go back to step 1 #[inline(always)] fn _cartesian_product_core<R, S>( n : usize, set_len : impl Fn(usize) -> usize, mut assign_res : impl FnMut(usize, usize) -> R, mut cb : impl FnMut() -> S) { assert!(n > 0, "Cannot create cartesian product with number of domain == 0"); let mut more = true; let mut i = 0; let mut c = vec![0; n]; let n = n - 1; while more { assign_res(i, c[i]); if i == n { c[i] += 1; cb(); } if i < n { i += 1; } while c[i] == set_len(i) { // c[i] reach the length of set[i] c[i] = 0; if i == 0 { more = false; break; } i -= 1; c[i] += 1; } } } /// Create a cartesian product over given slice. The result will be a slice /// of borrowed `T`. /// /// # Parameters /// - `sets` A slice of slice(s) contains `T` elements. /// - `cb` A callback function. It will be called on each product. /// /// # Return /// A function return a slice of borrowed `T` element out of parameter `sets`. /// It return value as parameter of callback function `cb`. /// /// # Examples /// To print all cartesian product between [1, 2, 3] and [4, 5, 6]. /// ``` /// use permutator::cartesian_product; /// /// cartesian_product(&[&[1, 2, 3], &[4, 5, 6]], |product| { /// // First called will receive [1, 4] then [1, 5] then [1, 6] /// // then [2, 4] then [2, 5] and so on until [3, 6]. /// println!("{:?}", product); /// }); /// ``` pub fn cartesian_product<'a, T, F>( sets : &'a [&[T]], mut cb : F) where T : 'a, for<'r> F : FnMut(&'r [&'a T]) + 'a { let mut result = vec![&sets[0][0]; sets.len()]; let copied = result.as_slice() as *const [&T]; unsafe { // It'd safe to use pointer here because internally, // the callback will be called after result mutation closure // and it will wait until the callback function return to // resume mutate the result again. _cartesian_product_core( sets.len(), #[inline(always)] |i| { sets[i].len() }, #[inline(always)] |i, c| { result[i] = &sets[i][c]; }, #[inline(always)] || { cb(&*copied); }); } } /// Similar to safe [cartesian_product function](fn.cartesian_product.html) /// except the way it return the product. /// It return result through mutable pointer to result assuming the /// pointer is valid. It'll notify caller on each new result via empty /// callback function. /// # Parameters /// - `sets` A raw sets of data to get a cartesian product. /// - `result` A mutable pointer to slice of length equals to `sets.len()` /// - `cb` A callback function which will be called after new product /// in `result` is set. /// # Return /// This function return result through function's parameter `result` and /// notify caller that new result is available through `cb` callback function. /// # Unsafe /// This function is unsafe because it may dereference a dangling pointer, /// may cause data race if multiple threads read/write to the same memory, /// and all of those unsafe Rust condition will be applied here. /// # Rationale /// The safe [cartesian_product function](fn.cartesian_product.html) /// return value in callback parameter. It limit the lifetime of return /// product to be valid only inside it callback. To use it outside /// callback scope, it need to copy the value which will have performance /// penalty. Therefore, jeopardize it own goal of being fast. This /// function provide alternative way that sacrifice safety for performance. /// /// # Example /// The scenario is we want to get cartesian product from single source of data /// then distribute the product to two workers which read each combination /// then do something about it, which in this example, simply print it. /// ``` /// use permutator::unsafe_cartesian_product; /// use std::fmt::Debug; /// // All shared data consumer will get call throught this trait /// trait Consumer { /// fn consume(&self); // need to be ref due to rule of only ref mut is permit at a time /// } /// /// struct Worker1<'a, T : 'a> { /// data : &'a[&'a T] // Store ref to cartesian product. /// } /// /// impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { /// fn consume(&self) { /// // read new share cartesian product and do something about it, in this case simply print it. /// println!("Work1 has {:?}", self.data); /// } /// } /// /// struct Worker2<'a, T : 'a> { /// data : &'a[&'a T] // Store ref to cartesian product. /// } /// /// impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { /// fn consume(&self) { /// // read new share cartesian product and do something about it, in this case simply print it. /// println!("Work2 has {:?}", self.data); /// } /// } /// /// unsafe fn start_cartesian_product_process<'a>(data : &'a[&'a[i32]], cur_result : *mut [&'a i32], consumers : Vec<Box<Consumer + 'a>>) { /// unsafe_cartesian_product(data, cur_result, || { /// consumers.iter().for_each(|c| { /// c.consume(); /// }) /// }); /// } /// /// let data : &[&[i32]] = &[&[1, 2], &[3, 4, 5], &[6]]; /// let mut result = vec![&data[0][0]; data.len()]; /// /// unsafe { /// /// let shared = result.as_mut_slice() as *mut [&i32]; /// let worker1 = Worker1 { /// data : &result /// }; /// let worker2 = Worker2 { /// data : &result /// }; /// let consumers : Vec<Box<Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; /// start_cartesian_product_process(data, shared, consumers); /// } /// ``` /// # See /// - [cartesian_product function](fn.cartesian_product.html) pub unsafe fn unsafe_cartesian_product<'a, T>(sets : &'a[&[T]], result : *mut [&'a T], cb : impl FnMut()) { _cartesian_product_core( sets.len(), #[inline(always)] |i| { sets[i].len() }, #[inline(always)] |i, c| { (*result)[i] = &sets[i][c]; }, cb); } /// Similar to safe [cartesian_product function](fn.cartesian_product.html) /// except the way it return the product. /// It return result through Rc<RefCell<>> to mutable slice of result. /// It'll notify caller on each new result via empty callback function. /// # Parameters /// - `sets` A raw sets of data to get a cartesian product. /// - `result` An Rc<RefCell<>> contains mutable slice of length equals to `sets.len()` /// - `cb` A callback function which will be called after new product /// in `result` is set. /// # Return /// This function return result through function's parameter `result` and /// notify caller that new result is available through `cb` callback function. /// # Rationale /// The safe [cartesian product function](fn.cartesian_product.html) return value in /// callback parameter. It limit the lifetime of return combination to be /// valid only inside it callback. To use it outside callback scope, it /// need to copy the value which will have performance penalty. Therefore, /// jeopardize it own goal of being fast. This function provide alternative /// safe way to share result which is roughly 50% slower to unsafe counterpart. /// The performance is on par with using [CartesianProduct](struct.CartesianProductIterator.html#method.next_into_cell) /// iterator. /// /// # Example /// The scenario is we want to get cartesian product from single source of data /// then distribute the product to two workers which read each combination /// then do something about it, which in this example, simply print it. /// ``` /// use permutator::cartesian_product_cell; /// use std::fmt::Debug; /// use std::rc::Rc; /// use std::cell::RefCell; /// /// // All shared data consumer will get call throught this trait /// trait Consumer { /// fn consume(&self); // need to be ref due to rule of only ref mut is permit at a time /// } /// /// struct Worker1<'a, T : 'a> { /// data : Rc<RefCell<&'a mut[&'a T]>> // Store ref to cartesian product. /// } /// /// impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { /// fn consume(&self) { /// // read new share cartesian product and do something about it, in this case simply print it. /// println!("Work1 has {:?}", self.data.borrow()); /// } /// } /// /// struct Worker2<'a, T : 'a> { /// data : Rc<RefCell<&'a mut[&'a T]>> // Store ref to cartesian product. /// } /// /// impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { /// fn consume(&self) { /// // read new share cartesian product and do something about it, in this case simply print it. /// println!("Work2 has {:?}", self.data.borrow()); /// } /// } /// /// fn start_cartesian_product_process<'a>(data : &'a[&'a[i32]], cur_result : Rc<RefCell<&'a mut [&'a i32]>>, consumers : Vec<Box<Consumer + 'a>>) { /// cartesian_product_cell(data, cur_result, || { /// consumers.iter().for_each(|c| { /// c.consume(); /// }) /// }); /// } /// /// let data : &[&[i32]] = &[&[1, 2], &[3, 4, 5], &[6]]; /// let mut result = vec![&data[0][0]; data.len()]; /// /// let shared = Rc::new(RefCell::new(result.as_mut_slice())); /// let worker1 = Worker1 { /// data : Rc::clone(&shared) /// }; /// let worker2 = Worker2 { /// data : Rc::clone(&shared) /// }; /// let consumers : Vec<Box<Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; /// start_cartesian_product_process(data, shared, consumers); /// ``` /// # See /// - [cartesian_product function](fn.cartesian_product.html) pub fn cartesian_product_cell<'a, T>(sets : &'a[&[T]], result : Rc<RefCell<&'a mut [&'a T]>>, cb : impl FnMut()) { _cartesian_product_core( sets.len(), #[inline(always)] |i| { sets[i].len() }, #[inline(always)] |i, c| { result.borrow_mut()[i] = &sets[i][c]; }, cb); } /// Similar to safe [cartesian_product function](fn.cartesian_product.html) /// except the way it return the product. /// It return result through Rc<RefCell<>> to mutable slice of result. /// It'll notify caller on each new result via empty callback function. /// # Parameters /// - `sets` A raw sets of data to get a cartesian product. /// - `result` An Rc<RefCell<>> contains mutable slice of length equals to `sets.len()` /// - `cb` A callback function which will be called after new product /// in `result` is set. /// # Return /// This function return result through function's parameter `result` and /// notify caller that new result is available through `cb` callback function. /// # Rationale /// The safe [cartesian product function](fn.cartesian_product.html) return value in /// callback parameter. It limit the lifetime of return combination to be /// valid only inside it callback. To use it outside callback scope, it /// need to copy the value which will have performance penalty. Therefore, /// jeopardize it own goal of being fast. This function provide alternative /// safe way to share result which is roughly 50% slower to unsafe counterpart. /// The performance is on roughly 15%-20% slower than [CartesianProduct](struct.CartesianProductIterator.html) /// iterator in uncontrol test environment. /// /// # Example /// The scenario is we want to get cartesian product from single source of data /// then distribute the product to two workers which read each combination /// then do something about it, which in this example, simply print it. /// ``` /// use std::thread; /// use std::sync::{Arc, RwLock}; /// use std::sync::mpsc; /// use std::sync::mpsc::{Receiver, SyncSender}; /// use permutator::cartesian_product_sync; /// /// fn start_cartesian_product_process<'a>(data : &'a[&[i32]], cur_result : Arc<RwLock<Vec<&'a i32>>>, notifier : Vec<SyncSender<Option<()>>>, release_recv : Receiver<()>) { /// use std::time::Instant; /// let timer = Instant::now(); /// let mut counter = 0; /// cartesian_product_sync(data, cur_result, || { /// notifier.iter().for_each(|n| { /// n.send(Some(())).unwrap(); // notify every thread that new data available /// }); /// /// for _ in 0..notifier.len() { /// release_recv.recv().unwrap(); // block until all thread reading data notify on read completion /// } /// /// counter += 1; /// }); /// /// notifier.iter().for_each(|n| {n.send(None).unwrap()}); // notify every thread that there'll be no more data. /// /// println!("Done {} combinations with 2 workers in {:?}", counter, timer.elapsed()); /// } /// let k = 7; /// let data : &[&[i32]]= &[&[1, 2, 3], &[4, 5], &[6]]; /// let result = vec![&data[0][0]; k]; /// let result_sync = Arc::new(RwLock::new(result)); /// /// // workter thread 1 /// let (t1_send, t1_recv) = mpsc::sync_channel::<Option<()>>(0); /// let (main_send, main_recv) = mpsc::sync_channel(0); /// let t1_local = main_send.clone(); /// let t1_dat = Arc::clone(&result_sync); /// thread::spawn(move || { /// while let Some(_) = t1_recv.recv().unwrap() { /// let result : &Vec<&i32> = &*t1_dat.read().unwrap(); /// // println!("Thread1: {:?}", result); /// t1_local.send(()).unwrap(); // notify generator thread that reference is no longer need. /// } /// println!("Thread1 is done"); /// }); /// /// // worker thread 2 /// let (t2_send, t2_recv) = mpsc::sync_channel::<Option<()>>(0); /// let t2_dat = Arc::clone(&result_sync); /// let t2_local = main_send.clone(); /// thread::spawn(move || { /// while let Some(_) = t2_recv.recv().unwrap() { /// let result : &Vec<&i32> = &*t2_dat.read().unwrap(); /// // println!("Thread2: {:?}", result); /// t2_local.send(()).unwrap(); // notify generator thread that reference is no longer need. /// } /// println!("Thread2 is done"); /// }); /// /// // main thread that generate result /// thread::spawn(move || { /// start_cartesian_product_process(data, result_sync, vec![t1_send, t2_send], main_recv); /// }).join().unwrap(); /// ``` /// # See /// - [cartesian_product function](fn.cartesian_product.html) pub fn cartesian_product_sync<'a, T>(sets : &'a[&[T]], result : Arc<RwLock<Vec<&'a T>>>, cb : impl FnMut()) { _cartesian_product_core( sets.len(), #[inline(always)] |i| { sets[i].len() }, #[inline(always)] |i, c| { result.write().unwrap()[i] = &sets[i][c]; }, cb); } /// Create a cartesian product over itself. The result will be a slice /// of borrowed `T`. /// /// # Parameters /// - `set` A slice of slice(s) contains `T` elements. /// - `n` How many time to create a product over `set` /// - `cb` A callback function. It will be called on each product. /// /// # Return /// A function return a slice of borrowed `T` element out of parameter `sets`. /// It return value as parameter of callback function `cb`. /// /// # Examples /// To print all cartesian product between [1, 2, 3] and [4, 5, 6]. /// ``` /// use permutator::self_cartesian_product; /// /// self_cartesian_product(&[1, 2, 3], 3, |product| { /// // First called will receive [1, 4] then [1, 5] then [1, 6] /// // then [2, 4] then [2, 5] and so on until [3, 6]. /// println!("{:?}", product); /// }); /// ``` pub fn self_cartesian_product<'a, T, F>(set : &'a [T], n : usize, mut cb : F) where T : 'a, for<'r> F : FnMut(&'r [&'a T]) + 'a { let mut result = vec![&set[0]; n]; let copied = result.as_slice() as *const [&T]; unsafe { // It'd safe to use pointer here because internally, // the callback will be called after result mutation closure // and it will wait until the callback function return to // resume mutate the result again. _cartesian_product_core( n, #[inline(always)] |_| { set.len() }, #[inline(always)] |i, c| { result[i] = &set[c]; }, #[inline(always)] || { cb(&*copied); }); } } /// Similar to safe [self_cartesian_product function](fn.self_cartesian_product.html) /// except the way it return the product. /// It return result through mutable pointer to result assuming the /// pointer is valid. It'll notify caller on each new result via empty /// callback function. /// # Parameters /// - `set` A raw sets of data to get a cartesian product. /// - `n` How many time to create a product on `set` parameter. /// - `result` A mutable pointer to slice of length equals to `sets.len()` /// - `cb` A callback function which will be called after new product /// in `result` is set. /// # Return /// This function return result through function's parameter `result` and /// notify caller that new result is available through `cb` callback function. /// # Unsafe /// This function is unsafe because it may dereference a dangling pointer, /// may cause data race if multiple threads read/write to the same memory, /// and all of those unsafe Rust condition will be applied here. /// # Rationale /// The safe [self_cartesian_product function](fn.self_cartesian_product.html) /// return value in callback parameter. It limit the lifetime of return /// product to be valid only inside it callback. To use it outside /// callback scope, it need to copy the value which will have performance /// penalty. Therefore, jeopardize it own goal of being fast. This /// function provide alternative way that sacrifice safety for performance. /// /// # Example /// The scenario is we want to get cartesian product from single source of data /// then distribute the product to two workers which read each combination /// then do something about it, which in this example, simply print it. /// ``` /// use permutator::unsafe_self_cartesian_product; /// use std::fmt::Debug; /// // All shared data consumer will get call throught this trait /// trait Consumer { /// fn consume(&self); // need to be ref due to rule of only ref mut is permit at a time /// } /// /// struct Worker1<'a, T : 'a> { /// data : &'a[&'a T] // Store ref to cartesian product. /// } /// /// impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { /// fn consume(&self) { /// // read new share cartesian product and do something about it, in this case simply print it. /// println!("Work1 has {:?}", self.data); /// } /// } /// /// struct Worker2<'a, T : 'a> { /// data : &'a[&'a T] // Store ref to cartesian product. /// } /// /// impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { /// fn consume(&self) { /// // read new share cartesian product and do something about it, in this case simply print it. /// println!("Work2 has {:?}", self.data); /// } /// } /// /// unsafe fn start_cartesian_product_process<'a>(data : &'a[i32], n : usize, cur_result : *mut [&'a i32], consumers : Vec<Box<Consumer + 'a>>) { /// unsafe_self_cartesian_product(data, n, cur_result, || { /// consumers.iter().for_each(|c| { /// c.consume(); /// }) /// }); /// } /// /// let data : &[i32] = &[1, 2, 3]; /// let n = 3; /// let mut result = vec![&data[0]; n]; /// /// unsafe { /// /// let shared = result.as_mut_slice() as *mut [&i32]; /// let worker1 = Worker1 { /// data : &result /// }; /// let worker2 = Worker2 { /// data : &result /// }; /// let consumers : Vec<Box<Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; /// start_cartesian_product_process(data, n, shared, consumers); /// } /// ``` /// # See /// - [cartesian_product function](fn.cartesian_product.html) pub unsafe fn unsafe_self_cartesian_product<'a, T>(set : &'a[T], n : usize, result : *mut [&'a T], cb : impl FnMut()) { _cartesian_product_core( n, #[inline(always)] |_| { set.len() }, #[inline(always)] |i, c| { (*result)[i] = &set[c]; }, cb); } /// Similar to safe [cartesian_product function](fn.self_cartesian_product.html) /// except the way it return the product. /// It return result through Rc<RefCell<>> to mutable slice of result. /// It'll notify caller on each new result via empty callback function. /// # Parameters /// - `set` A raw sets of data to get a cartesian product. /// - `n` How many time to create a product of `set` parameter /// - `result` An Rc<RefCell<>> contains mutable slice of length equals to `sets.len()` /// - `cb` A callback function which will be called after new product /// in `result` is set. /// # Return /// This function return result through function's parameter `result` and /// notify caller that new result is available through `cb` callback function. /// # Rationale /// The safe [cartesian product function](fn.cartesian_product.html) return value in /// callback parameter. It limit the lifetime of return combination to be /// valid only inside it callback. To use it outside callback scope, it /// need to copy the value which will have performance penalty. Therefore, /// jeopardize it own goal of being fast. This function provide alternative /// safe way to share result which is roughly 50% slower to unsafe counterpart. /// The performance is on par with using [CartesianProduct](struct.CartesianProductIterator.html#method.next_into_cell) /// iterator. /// /// # Example /// The scenario is we want to get cartesian product from single source of data /// then distribute the product to two workers which read each combination /// then do something about it, which in this example, simply print it. /// ``` /// use permutator::self_cartesian_product_cell; /// use std::fmt::Debug; /// use std::rc::Rc; /// use std::cell::RefCell; /// /// // All shared data consumer will get call throught this trait /// trait Consumer { /// fn consume(&self); // need to be ref due to rule of only ref mut is permit at a time /// } /// /// struct Worker1<'a, T : 'a> { /// data : Rc<RefCell<&'a mut[&'a T]>> // Store ref to cartesian product. /// } /// /// impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { /// fn consume(&self) { /// // read new share cartesian product and do something about it, in this case simply print it. /// println!("Work1 has {:?}", self.data.borrow()); /// } /// } /// /// struct Worker2<'a, T : 'a> { /// data : Rc<RefCell<&'a mut[&'a T]>> // Store ref to cartesian product. /// } /// /// impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { /// fn consume(&self) { /// // read new share cartesian product and do something about it, in this case simply print it. /// println!("Work2 has {:?}", self.data.borrow()); /// } /// } /// /// fn start_cartesian_product_process<'a>(data : &'a[i32], n : usize, cur_result : Rc<RefCell<&'a mut [&'a i32]>>, consumers : Vec<Box<Consumer + 'a>>) { /// self_cartesian_product_cell(data, n, cur_result, || { /// consumers.iter().for_each(|c| { /// c.consume(); /// }) /// }); /// } /// /// let data : &[i32] = &[1, 2, 3]; /// let n = 3; /// let mut result = vec![&data[0]; n]; /// /// let shared = Rc::new(RefCell::new(result.as_mut_slice())); /// let worker1 = Worker1 { /// data : Rc::clone(&shared) /// }; /// let worker2 = Worker2 { /// data : Rc::clone(&shared) /// }; /// let consumers : Vec<Box<Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; /// start_cartesian_product_process(data, n, shared, consumers); /// ``` /// # See /// - [cartesian_product function](fn.cartesian_product.html) pub fn self_cartesian_product_cell<'a, T>(set : &'a[T], n : usize, result : Rc<RefCell<&'a mut [&'a T]>>, cb : impl FnMut()) { _cartesian_product_core( n, #[inline(always)] |_| { set.len() }, #[inline(always)] |i, c| { result.borrow_mut()[i] = &set[c]; }, cb); } /// Similar to safe [self_cartesian_product function](fn.self_cartesian_product.html) /// except the way it return the product. /// It return result through Arc<RwLock<>> to mutable slice of result. /// It'll notify caller on each new result via empty callback function. /// # Parameters /// - `set` A raw set of data to get a cartesian product. /// - `n` how many times to do the product of `set` parameter /// - `result` An Arc<RwLock<>> contains mutable slice of length equals to parameter `n` /// - `cb` A callback function which will be called after new product /// in `result` is set. /// # Return /// This function return result through function's parameter `result` and /// notify caller that new result is available through `cb` callback function. /// # Rationale /// The safe [cartesian product function](fn.self_cartesian_product.html) return value in /// callback parameter. It limit the lifetime of return combination to be /// valid only inside it callback. To use it outside callback scope, it /// need to copy the value which will have performance penalty. Therefore, /// jeopardize it own goal of being fast. This function provide alternative /// safe way to share result which is roughly 50% slower to unsafe counterpart. /// The performance is on roughly 15%-20% slower than [SelfCartesianProduct](struct.SelfCartesianProductIterator.html) /// iterator in uncontrol test environment. /// /// # Example /// The scenario is we want to get cartesian product from single source of data /// then distribute the product to two workers which read each combination /// then do something about it, which in this example, simply print it. /// ``` /// use std::thread; /// use std::sync::{Arc, RwLock}; /// use std::sync::mpsc; /// use std::sync::mpsc::{Receiver, SyncSender}; /// use permutator::self_cartesian_product_sync; /// /// fn start_cartesian_product_process<'a>(data : &'a[i32], n : usize, cur_result : Arc<RwLock<Vec<&'a i32>>>, notifier : Vec<SyncSender<Option<()>>>, release_recv : Receiver<()>) { /// use std::time::Instant; /// let timer = Instant::now(); /// let mut counter = 0; /// self_cartesian_product_sync(data, n, cur_result, || { /// notifier.iter().for_each(|n| { /// n.send(Some(())).unwrap(); // notify every thread that new data available /// }); /// /// for _ in 0..notifier.len() { /// release_recv.recv().unwrap(); // block until all thread reading data notify on read completion /// } /// /// counter += 1; /// }); /// /// notifier.iter().for_each(|n| {n.send(None).unwrap()}); // notify every thread that there'll be no more data. /// /// println!("Done {} combinations with 2 workers in {:?}", counter, timer.elapsed()); /// } /// /// let data : &[i32]= &[1, 2, 3]; /// let n = 3; /// let result = vec![&data[0]; n]; /// let result_sync = Arc::new(RwLock::new(result)); /// /// // workter thread 1 /// let (t1_send, t1_recv) = mpsc::sync_channel::<Option<()>>(0); /// let (main_send, main_recv) = mpsc::sync_channel(0); /// let t1_local = main_send.clone(); /// let t1_dat = Arc::clone(&result_sync); /// thread::spawn(move || { /// while let Some(_) = t1_recv.recv().unwrap() { /// let result : &Vec<&i32> = &*t1_dat.read().unwrap(); /// // println!("Thread1: {:?}", result); /// t1_local.send(()).unwrap(); // notify generator thread that reference is no longer need. /// } /// println!("Thread1 is done"); /// }); /// /// // worker thread 2 /// let (t2_send, t2_recv) = mpsc::sync_channel::<Option<()>>(0); /// let t2_dat = Arc::clone(&result_sync); /// let t2_local = main_send.clone(); /// thread::spawn(move || { /// while let Some(_) = t2_recv.recv().unwrap() { /// let result : &Vec<&i32> = &*t2_dat.read().unwrap(); /// // println!("Thread2: {:?}", result); /// t2_local.send(()).unwrap(); // notify generator thread that reference is no longer need. /// } /// println!("Thread2 is done"); /// }); /// /// // main thread that generate result /// thread::spawn(move || { /// start_cartesian_product_process(data, n, result_sync, vec![t1_send, t2_send], main_recv); /// }).join().unwrap(); /// ``` /// # See /// - [cartesian_product function](fn.cartesian_product.html) pub fn self_cartesian_product_sync<'a, T>(set : &'a[T], n : usize, result : Arc<RwLock<Vec<&'a T>>>, cb : impl FnMut()) { _cartesian_product_core( n, #[inline(always)] |_| { set.len() }, #[inline(always)] |i, c| { result.write().unwrap()[i] = &set[c]; }, cb); } /// # Deprecated /// This combination family is now deprecated. /// Consider using [large_combination function](fn.large_combination.html) /// instead. This is because current implementation need to copy every ref /// on every iteration which is inefficient. /// On uncontroll test environment, this iterator take 2.41s to iterate over /// 30,045,015 combinations. The [large_combination function](fn.large_combination.html) /// took only 208.84ms. Beside speed, it also theoritically support up to 2^32 elements. /// If no more efficient implementation is available for some certain time period, /// this function will be officially mark with #[deprecated]. /// /// Generate a combination out of given `domain`. /// It call `cb` to several times to return each combination. /// It's similar to [struct GosperCombination](struct.GosperCombinationIterator.html) but /// slightly faster in uncontrol test environment. /// # Parameters /// - `domain` is a slice containing the source data, AKA 'domain' /// - `r` is a size of each combination, AKA 'range' size /// - `cb` is a callback function that will get call several times. /// Each call will have a slice of combination pass as callback parameter. /// # Returns /// The function will return combination via callback function. It will /// keep calling until no further combination can be found then it /// return control to called. /// # Example /// ``` /// use permutator::combination; /// combination(&[1, 2, 3, 4, 5], 3, |c| { /// // called multiple times. /// // Each call have [1, 2, 3], [1, 2, 4], [1, 3, 4], [2, 3, 4] /// // [1, 2, 5], [1, 3, 5], [2, 3, 5], [1, 4, 5], [2, 4, 5], /// // and [3, 4, 5] respectively. /// println!("{:?}", c); /// }); /// ``` /// # Limitation /// Gosper algorithm need to know the MSB (most significant bit). /// The current largest known MSB data type is u128. /// This make the implementation support up to 128 elements slice. /// # See /// - [GosperCombination](struct.GospoerCombination.html) pub fn combination<T>(domain: &[T], r : usize, mut cb : impl FnMut(&[&T]) -> ()) { let (mut combination, mut map) = create_k_set(domain, r); cb(&combination); while let Some(_) = swap_k((&mut combination, &mut map), domain) { cb(&combination); } } /// # Deprecated /// See [combination function](fn.combination.html) for reason of /// deprecation /// /// Similar to safe [combination function](fn.combination.html) except /// the way it return the combination. /// It return result through mutable pointer to result assuming the /// pointer is valid. It'll notify caller on each new result via empty /// callback function. /// # Parameters /// - `domain` A raw data to get combination. /// - `r` A size of each combination. /// - `result` A mutable pointer to slice of length equals to `r` /// - `cb` A callback function which will be called after new combination /// in `result` is set. /// # Return /// This function return result through function's parameter `result` and /// notify caller that new result is available through `cb` callback function. /// # Unsafe /// This function is unsafe because it may dereference a dangling pointer, /// may cause data race if multiple threads read/write to the same memory, /// and all of those unsafe Rust condition will be applied here. /// # Rationale /// The safe [combination function](fn.combination.html) return value in /// callback parameter. It limit the lifetime of return combination to be /// valid only inside it callback. To use it outside callback scope, it /// need to copy the value which will have performance penalty. Therefore, /// jeopardize it own goal of being fast. This function provide alternative /// way that sacrifice safety for performance. /// # Example /// The scenario is we want to get combination from single source of data /// then distribute the combination to two workers which read each combination /// then do something about it, which in this example, simply print it. /// /// ``` /// use permutator::unsafe_combination; /// use std::fmt::Debug; /// // define a trait that represent a data consumer /// trait Consumer { /// fn consume(&self); // cannot mut data because rule of no more than 1 ref mut at a time. /// } /// /// struct Worker1<'a, T : 'a> { /// data : &'a[&'a T] // A reference to each combination /// } /// /// impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { /// fn consume(&self) { /// // Read data then do something about it. In this case, simply print it. /// println!("Work1 has {:?}", self.data); /// } /// } /// /// struct Worker2<'a, T : 'a> { /// data : &'a[&'a T] // A reference to each combination /// } /// /// impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { /// fn consume(&self) { /// // Read data then do something about it. In this case, simply print it. /// println!("Work2 has {:?}", self.data); /// } /// } /// /// unsafe fn start_combination_process<'a>(data : &'a[i32], cur_result : *mut [&'a i32], k : usize, consumers : Vec<Box<Consumer + 'a>>) { /// unsafe_combination(data, k, cur_result, || { /// consumers.iter().for_each(|c| { /// c.consume(); /// }) /// }); /// } /// let k = 3; /// let data = &[1, 2, 3, 4, 5]; /// let mut result = vec![&data[0]; k]; /// /// unsafe { /// /// let shared = result.as_mut_slice() as *mut [&i32]; /// let worker1 = Worker1 { /// data : &result /// }; /// let worker2 = Worker2 { /// data : &result /// }; /// let consumers : Vec<Box<Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; /// start_combination_process(data, shared, k, consumers); /// } /// ``` /// # See /// - [combination function](fn.combination.html) pub unsafe fn unsafe_combination<'a, T>(domain: &'a[T], r : usize, result : *mut [&'a T], mut cb : impl FnMut() -> ()) { let mut mask = 0u128; unsafe_create_k_set(domain, r, result, &mut mask); cb(); while let Some(_) = swap_k((&mut *result, &mut mask), domain) { cb(); } } /// # Deprecated /// See [combination function](fn.combination.html) for reason of /// deprecation /// /// Similar to [combination function](fn.combination.html) except /// the way it return the combination. /// It return result through Rc<RefCell<>> to mutable slice of result. /// It'll notify caller on each new result via empty callback function. /// # Parameters /// - `domain` A raw data to get combination. /// - `r` A size of each combination. /// - `result` An Rc<RefCell<>> to mutable slice of length equals to `r` /// - `cb` A callback function which will be called after new combination /// in `result` is set. /// # Return /// This function return result through function's parameter `result` and /// notify caller that new result is available through `cb` callback function. /// # Rationale /// The safe [combination function](fn.combination.html) return value in /// callback parameter. It limit the lifetime of return combination to be /// valid only inside it callback. To use it outside callback scope, it /// need to copy the value which will have performance penalty. Therefore, /// jeopardize it own goal of being fast. This function provide alternative /// safe way to share result which is roughly 50% slower to unsafe counterpart. /// The performance is on par with using /// [GosperCombinationIterator with next_into_cell function](struct.GosperCombinationIterator.html#method.next_into_cell). /// # Example /// The scenario is we want to get combination from single source of data /// then distribute the combination to two workers which read each combination /// then do something about it, which in this example, simply print it. /// /// ``` /// use permutator::combination_cell; /// use std::fmt::Debug; /// use std::rc::Rc; /// use std::cell::RefCell; /// /// // define a trait that represent a data consumer /// trait Consumer { /// fn consume(&self); // cannot mut data because rule of no more than 1 ref mut at a time. /// } /// /// struct Worker1<'a, T : 'a> { /// data : Rc<RefCell<&'a mut[&'a T]>> // A reference to each combination /// } /// /// impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { /// fn consume(&self) { /// // Read data then do something about it. In this case, simply print it. /// println!("Work1 has {:?}", self.data.borrow()); /// } /// } /// /// struct Worker2<'a, T : 'a> { /// data : Rc<RefCell<&'a mut[&'a T]>> // A reference to each combination /// } /// /// impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { /// fn consume(&self) { /// // Read data then do something about it. In this case, simply print it. /// println!("Work2 has {:?}", self.data.borrow()); /// } /// } /// /// fn start_combination_process<'a>(data : &'a[i32], cur_result : Rc<RefCell<&'a mut[&'a i32]>>, k : usize, consumers : Vec<Box<Consumer + 'a>>) { /// combination_cell(data, k, cur_result, || { /// consumers.iter().for_each(|c| { /// c.consume(); /// }) /// }); /// } /// let k = 3; /// let data = &[1, 2, 3, 4, 5]; /// let mut result = vec![&data[0]; k]; /// /// let shared = Rc::new(RefCell::new(result.as_mut_slice())); /// let worker1 = Worker1 { /// data : Rc::clone(&shared) /// }; /// let worker2 = Worker2 { /// data : Rc::clone(&shared) /// }; /// let consumers : Vec<Box<Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; /// start_combination_process(data, shared, k, consumers); /// ``` /// # See /// - [combination function](fn.combination.html) pub fn combination_cell<'a, T>(domain: &'a[T], r : usize, result : Rc<RefCell<&'a mut [&'a T]>>, mut cb : impl FnMut() -> ()) { let mut mask = 0u128; create_k_set_in_cell(domain, r, &result, &mut mask); cb(); while let Some(_) = swap_k_in_cell((&result, &mut mask), domain) { cb(); } } /// # Deprecated /// See [combination function](fn.combination.html) for reason of /// deprecation /// /// Similar to [combination function](fn.combination.html) except /// the way it return the combination. /// It return result through Rc<RefCell<>> to mutable slice of result. /// It'll notify caller on each new result via empty callback function. /// # Parameters /// - `domain` A raw data to get combination. /// - `r` A size of each combination. /// - `result` An Rc<RefCell<>> to mutable slice of length equals to `r` /// - `cb` A callback function which will be called after new combination /// in `result` is set. /// # Return /// This function return result through function's parameter `result` and /// notify caller that new result is available through `cb` callback function. /// # Rationale /// The [combination function](fn.combination.html) return value in /// callback parameter. It limit the lifetime of return combination to be /// valid only inside it callback. To use it on different thread, it /// need to copy the value which will have performance penalty. /// This function provide alternative way to share data between thread. /// It will write new result into Arc<RwLock<>> of Vec owned inside RwLock. /// Since it write data directly into Vec, other threads won't know that /// new data is wrote. The combination generator thread need to notify /// other threads via channel. This introduce another problem. /// Since combination generator write data directly into shared memory address, /// it need to know if all other threads are done using the data. /// Otherwise, in worst case, combination generator thread may dominate all other /// threads and hold write lock until it done generate every value. /// To solve such issue, combination generator thread need to get notified /// when each thread has done using the data. /// # Example /// The scenario is we want to get combination from single source of data /// then distribute the combination to two workers which read each combination /// then do something about it, which in this example, simply print it. /// /// ``` /// use permutator::combination_sync; /// use std::fmt::Debug; /// use std::sync::{Arc, RwLock}; /// use std::sync::mpsc; /// use std::sync::mpsc::{Receiver, SyncSender}; /// use std::thread; /// /// fn start_combination_process<'a>(data : &'a[i32], cur_result : Arc<RwLock<Vec<&'a i32>>>, k : usize, notifier : Vec<SyncSender<Option<()>>>, release_recv : Receiver<()>) { /// use std::time::Instant; /// let timer = Instant::now(); /// let mut counter = 0; /// combination_sync(data, k, cur_result, || { /// notifier.iter().for_each(|n| { /// n.send(Some(())).unwrap(); // notify every thread that new data available /// }); /// /// for _ in 0..notifier.len() { /// release_recv.recv().unwrap(); // block until all thread reading data notify on read completion /// } /// /// counter += 1; /// }); /// /// notifier.iter().for_each(|n| {n.send(None).unwrap()}); // notify every thread that there'll be no more data. /// /// println!("Done {} combinations with 2 workers in {:?}", counter, timer.elapsed()); /// } /// let k = 3; /// let data = &[1, 2, 3, 4, 5]; /// let result = vec![&data[0]; k]; /// let result_sync = Arc::new(RwLock::new(result)); /// /// // workter thread 1 /// let (t1_send, t1_recv) = mpsc::sync_channel::<Option<()>>(0); /// let (main_send, main_recv) = mpsc::sync_channel(0); /// let t1_local = main_send.clone(); /// let t1_dat = Arc::clone(&result_sync); /// thread::spawn(move || { /// while let Some(_) = t1_recv.recv().unwrap() { /// let result : &Vec<&i32> = &*t1_dat.read().unwrap(); /// println!("Thread1: {:?}", result); /// t1_local.send(()).unwrap(); // notify generator thread that reference is no longer neeed. /// } /// println!("Thread1 is done"); /// }); /// /// // worker thread 2 /// let (t2_send, t2_recv) = mpsc::sync_channel::<Option<()>>(0); /// let t2_dat = Arc::clone(&result_sync); /// let t2_local = main_send.clone(); /// thread::spawn(move || { /// while let Some(_) = t2_recv.recv().unwrap() { /// let result : &Vec<&i32> = &*t2_dat.read().unwrap(); /// println!("Thread2: {:?}", result); /// t2_local.send(()).unwrap(); // notify generator thread that reference is no longer neeed. /// } /// println!("Thread2 is done"); /// }); /// /// // main thread that generate result /// thread::spawn(move || { /// start_combination_process(data, result_sync, k, vec![t1_send, t2_send], main_recv); /// }).join().unwrap(); /// ``` /// # See /// - [combination function](fn.combination.html) pub fn combination_sync<'a, T>(domain: &'a[T], r : usize, result : Arc<RwLock<Vec<&'a T>>>, mut cb : impl FnMut() -> ()) { let mut mask = 0u128; create_k_set_sync(domain, r, &result, &mut mask); cb(); while let Some(_) = swap_k_sync((&result, &mut mask), domain) { cb(); } } /// A core logic that generate a combination /// /// # Parameters /// 1. slice of T - Source of combination /// 2. usize - size of combination. /// 3. closure - function to generate a first result. /// It tooks ref mut of cursor, ref of domain, and the size of combination. /// It return object to store result. /// 4. closure - function that set each element of result to some value. /// It tooks index of result, an index of domain, and a ref mut object to store result /// 5. closure - function that got call on each new combination. /// /// # Panic /// It panic when size of combination is larger that length of source. fn _core_large_combination<'a, T : 'a, R : 'a>( // source of combination domain : &'a [T], // combination size r : usize, // A closure that took ref mut of cursor, ref of domain, and the size of combination. It return object to store result // It take ownership of result from environment and move it into this function. first_result_fn : impl FnOnce(&mut Vec<usize>, &'a [T], usize) -> R, // A closure that took index of result, an index of domain, and object to store result mut next_result_fn : impl FnMut(usize, usize, &mut R), // A callback function that get once on each new combination. // The new combination is sent as ref as function paramter. mut cb : impl FnMut(&R)) { /// Move cursor and update result #[inline(always)] fn move_cur_res<'a, T, R>(c : &mut [usize], domain : &'a [T], result : &mut R, next_result_fn : &mut dyn FnMut(usize, usize, &mut R)) { let n = c.len(); let max = domain.len(); let mut i = c.len() - 1; if c[i] < max - n + i { c[i] += 1; next_result_fn(i, c[i], result); } else { // find where to start reset cursor while c[i] >= max - n + i { i -= 1; } c[i] += 1; next_result_fn(i, c[i], result); i += 1; // reset all cursor from `i + 1` (i..c.len()).for_each(|i| { c[i] = c[i - 1] + 1; next_result_fn(i, c[i], result); }); } } assert_ne!(r, 0, "The combination size cannot be 0"); assert!(domain.len() >= r, "The combination size cannot be larger than size of data"); let mut c : Vec<usize> = Vec::new(); let mut result = first_result_fn(&mut c, domain, r); cb(&result); let n = r - 1; c[n] += 1; if c[n] < domain.len() { next_result_fn(n, c[n], &mut result); cb(&result); } else { return; } while c[0] < domain.len() - r { // move cursor and update result move_cur_res(&mut c, domain, &mut result, &mut next_result_fn); cb(&result); } } /// Generate a r-combination from given domain and call callback function /// on each combination. /// /// # Parameter /// 1. `domain : &[T]` - A slice contain a domain to generate r-combination /// 2. `r : usize` - A size of combination /// 3. `cb : FnMut(&[&T])` - A callback that return each combination /// /// # Panic /// It panic when `r` > `domain.len()` pub fn large_combination<'a, T, F>(domain: &'a [T], r : usize, mut cb : F) where T : 'a, for<'r> F : FnMut(&'r[&'a T]) + 'a { let mut result : Vec<&T> = Vec::with_capacity(r); _core_large_combination(domain, r, #[inline(always)] |c, domain, r| { (0..r).for_each(|i| { result.push(&domain[i]); c.push(i); }); result }, #[inline(always)] |i, j, result| { result[i] = &domain[j]; }, #[inline(always)] |result| { cb(result); } ); } /// Generate a r-combination from given domain and call callback function /// on each combination. The result will be return into ref mut pointer. /// /// # Parameter /// 1. `domain : &[T]` - A slice contain a domain to generate r-combination /// 2. `r : usize` - A size of combination /// 3. `result : *mut [&T]` - A mutable pointer to store result /// 4. `cb : FnMut()` - A callback that notify caller on each combination /// /// # Panic /// - It panic when `r > domain.len()` or `r > result.len()` /// /// # Rationale /// This function took *mut [&T] to store result. It allow caller to easily share /// result outside callback function without copying/cloning each result. /// It sacrifice safety for performance. /// /// # Safety /// - It doesn't check whether the pointer is valid or not. /// - It doesn't free memory occupied by result. /// - It may cause data race /// - Mutating `result` may cause undesired behavior. /// - Storing `result` will get overwritten when new combination is return. /// - All other unsafe Rust condition may applied. pub unsafe fn unsafe_large_combination<'a, T : 'a>(domain: &'a [T], r : usize, result : *mut [&'a T], mut cb : impl FnMut()) { _core_large_combination(domain, r, #[inline(always)] |c, domain, r| { let result = &mut *result; (0..r).for_each(|i| { result[i] = &domain[i]; c.push(i); }); result }, #[inline(always)] |i, j, result| { result[i] = &domain[j]; }, #[inline(always)] |_| { cb(); } ); } /// Generate a r-combination from given domain and call callback function /// on each combination. The result will be return into Rc<RefCell<>>. /// /// # Parameter /// 1. `domain : &[T]` - A slice contain a domain to generate r-combination /// 2. `r : usize` - A size of combination /// 3. 'result : Rc<RefCell<&mut [&T]>>` - A result container object. /// 4. `cb : FnMut()` - A callback that notify caller on each combination /// /// # Panic /// It panic when `r > domain.len()` or `r > result.borrow().len()` /// /// # Rationale /// It allow easily safe sharing of result to some degree with minor /// performance overhead and some some usage constraint. /// - `result` will get overwritten on each new combination. /// - Storing `result` will get overwritten when new combination is return. pub fn large_combination_cell<'a, T : 'a>(domain: &'a[T], r : usize, result : Rc<RefCell<&'a mut [&'a T]>>, mut cb : impl FnMut() -> ()) { _core_large_combination(domain, r, #[inline(always)] |c, domain, r| { (0..r).for_each(|i| { result.borrow_mut()[i] = &domain[i]; c.push(i); }); result }, #[inline(always)] |i, j, result| { result.borrow_mut()[i] = &domain[j]; }, #[inline(always)] |_| { cb(); } ); } /// Generate a r-combination from given domain and call callback function /// on each combination. The result will be return into Arc<RwLock<>>. /// /// # Parameter /// 1. `domain : &[T]` - A slice contain a domain to generate r-combination /// 2. `r : usize` - A size of combination /// 3. 'result : Arc<RwLock<Vec<&T>>>` - A result container object. /// 4. `cb : FnMut()` - A callback that notify caller on each combination /// /// # Panic /// It panic when `r > domain.len()` or `r > result.read().unwrap().len()` /// /// # Rationale /// It allow easily safe sharing of result with other thread to some degree /// with minor performance overhead and some some usage constraint. /// - `result` will get overwritten on each new combination. /// - Storing `result` will get overwritten when new combination is return. pub fn large_combination_sync<'a, T : 'a>(domain: &'a[T], r : usize, result : Arc<RwLock<Vec<&'a T>>>, mut cb : impl FnMut() -> ()) { _core_large_combination(domain, r, #[inline(always)] |c, domain, r| { { let mut writer = result.write().unwrap(); (0..r).for_each(|i| { writer[i] = &domain[i]; c.push(i); }); } result }, #[inline(always)] |i, j, result| { result.write().unwrap()[i] = &domain[j]; }, #[inline(always)] |_| { cb(); } ); } /// A core heap permutation algorithm. /// # Parameters /// - `n` size of entire data /// - `swap` a closure to swap the data /// - `cb` a callback function that get call on each permutation /// # Closure execution sequence /// 1. `swap` once /// 2. `cb` once /// 3. go to step 1 until permutation is `n` times fn _heap_permutation_core(n : usize, mut swap : impl FnMut(usize, usize), mut cb : impl FnMut()) { let mut c = vec![0; n]; let mut i = 0; while i < n { if c[i] < i { if i & 1 == 0 { // equals to mod 2 because it take only 0 and 1 aka last bit swap(0, i); } else { swap(c[i], i); } cb(); c[i] += 1; i = 0; } else { c[i] = 0; i += 1; } } } /// Heap permutation which permutate variable `d` in place and call `cb` function /// for each permutation done on `d`. /// /// # Parameter /// - `d` a data to be permuted. /// - `cb` a callback function that will be called several times for each permuted value. /// /// # Example /// ``` /// use permutator::heap_permutation; /// heap_permutation(&mut [1, 2, 3], |p| { /// // call multiple times. It'll print [1, 2, 3], [2, 1, 3], [3, 1, 2], /// // [1, 3, 2], [2, 3, 1], and [3, 2, 1] respectively. /// println!("{:?}", p); /// }); /// ``` /// # See /// - [k_permutation_sync](fn.k_permutation_sync.html) for example of /// how to implement multi-thread data sync /// - The [HeapPermutationIterator struct](struct.HeapPermutationIterator.html) /// provide alternate way of getting permutation but in iterative way. /// # Warning /// The permutation is done in place which mean the parameter `d` will be /// mutated. /// /// # Notes /// 1. The value passed to callback function will equals to value inside parameter `d`. /// /// # Breaking change from 0.3.x to 0.4 /// Since version 0.4.0, the first result return by this iterator /// will be the original value pub fn heap_permutation<'a, T>(d : &'a mut [T], mut cb : impl FnMut(&[T]) -> () + 'a) { let copied = d as *const [T]; unsafe { cb(&*copied); // It'd safe because the mutation on `d` will be done // before calling `cb` closure and until `cb` closure is return // the mutation closure won't get call. _heap_permutation_core( d.len(), #[inline(always)] |from, to| { d.swap(from, to); }, #[inline(always)] || { cb(&*copied) }); } } /// Heap permutation which permutate variable `d` in place and call `cb` function /// for each permutation done on `d`. /// /// # Parameter /// - `d` an Rc<RefCell<>> to mutable slice data to be permuted. /// - `cb` a callback function that will be called several times for each permuted value. /// /// # Example /// ``` /// use permutator::heap_permutation_cell; /// use std::rc::Rc; /// use std::cell::RefCell; /// let data : &mut[i32] = &mut [1, 2, 3]; /// let sharable = Rc::new(RefCell::new(data)); /// heap_permutation_cell(&sharable, || { /// // call other functions/objects that use `sharable` variable. /// }); /// ``` /// /// # Warning /// The permutation is done in place which mean the parameter `d` will be /// mutated. /// /// # Notes /// 1. The value passed to callback function will equals to value inside parameter `d`. /// /// # Breaking change from 0.3.x to 0.4 /// Since version 0.4.0, the first result return by this iterator /// will be the original value pub fn heap_permutation_cell<T>(d : &Rc<RefCell<&mut [T]>>, mut cb : impl FnMut() -> ()) { cb(); // need borrow expr outside function call because if the expr is // put inline within the function call, Rust runtime hold borrowed `d` // for an entire function call let n = d.borrow().len(); _heap_permutation_core( n, #[inline(always)] |from, to| { d.borrow_mut().swap(from, to); }, cb ); } /// Heap permutation which permutate variable `d` in place and call `cb` function /// for each permutation done on `d`. /// /// # Parameter /// - `d` an Rc<RefCell<>> to mutable slice data to be permuted. /// - `cb` a callback function that will be called several times for each permuted value. /// /// # Warning /// The permutation is done in place which mean the parameter `d` will be /// mutated. /// /// # Notes /// 1. The value passed to callback function will equals to value inside parameter `d`. /// /// # Breaking change from 0.3.x to 0.4 /// Since version 0.4.0, the first result return by this iterator /// will be the original value pub fn heap_permutation_sync<T>(d : &Arc<RwLock<Vec<T>>>, mut cb : impl FnMut() -> ()) { cb(); // need read lock expr outside function call because if the expr is // put inline within the function call, Rust runtime obtain the lock // for an entire function call let n = d.read().unwrap().len(); _heap_permutation_core( n, #[inline(always)] |from, to| { d.write().unwrap().swap(from, to); }, cb ); } /// A macro that perform core logic of k-permutation. /// /// # Parameters /// 1. `k` - The size of each permutation. /// 2. `n` - The total length of data /// 3. `swap_fn` - The closure that perform data swap /// 4. `cb` - The callback function that will return each permutation. #[allow(unused)] macro_rules! _k_permutation_core { ($k : expr, $n : expr, $swap_fn : expr, $permute_fn : expr, $cb : expr) => { if $n < $k { panic!("Cannot create k-permutation of size {} for data of length {}", $k, $n); } else if $k == 0 { // k = 0 mean mean permutation frame size is 0, it cannot have permutation return } $cb; $permute_fn; // generate all possible permutation for initial subset while let Some(_) = $swap_fn { // repeatly swap element $cb; $permute_fn; // generate all possible permutation per each subset } }; } /// Generate k-permutation over slice of `d`. For example: d = &[1, 2, 3]; k = 2. /// The result will be [1, 2], [2, 1], [1, 3], [3, 1], [2, 3], [3, 2] /// /// The implementation calculate each combination by [large_combination function](fn.large_combination.html) /// then apply Heap's algorithm. There's [KPermutationIterator struct](struct.KPermutationIterator.html) /// that also generate KPermutationIterator but in iterative style. /// The performance of this function is slightly faster than /// [KPermutationIterator struct](struct.KPermutationIterator.html) by about 15%-20% /// tested in uncontrol environment. /// /// # Examples /// The example below will generate 4-permutation over 6 data items. /// The first combination will be used to generate all permutation first. /// So the first three result will be [1, 2, 3, 4], [2, 1, 3, 4], [3, 1, 2, 4] /// as per Heap permutation algorithm. /// After all permutation for [1, 2, 3, 4] is calculated, it'll use Gospel /// algorithm to find next combination which is [1, 2, 3, 5] then /// permutate it until every permutation is done. /// It'll keep repeating above process until last combination, which is /// [3, 4, 5, 6], is completely permuted then the function will return. /// /// ``` /// use permutator::k_permutation; /// use std::time::{Instant}; /// /// let data = [1, 2, 3, 4, 5, 6]; /// let mut counter = 0; /// let timer = Instant::now(); /// /// k_permutation(&data, 4, |permuted| { /// // uncomment line below to print all k-permutation /// // println!("{}:{:?}", counter, permuted); /// counter += 1; /// }); /// println!("Done {} permuted in {:?}", counter, timer.elapsed()); /// ``` /// # Panic /// This function panic when `k == 0` or `k > d.len()` /// /// # Notes /// 1. This function doesn't support jumping into specific nth permutation because /// the permutation is out of lexicographic order per Heap's algorithm limitation. /// For jumping into specific position, it require lexicographic ordered permutation. /// 2. This function take callback function to speed up permutation processing. /// It will call the callback right in the middle of Heap's loop then continue /// the loop. /// 3. This function use single thread. /// /// # See /// - [Heap's algorithm in Wikipedia page, October 9, 2018](https://en.wikipedia.org/wiki/Heap%27s_algorithm) pub fn k_permutation<'a, T, F>(d : &'a [T], k : usize, mut cb : F) where T : 'a, for<'r> F : FnMut(&'r [&'a T]) + 'a { assert_ne!(k, 0); assert!(k <= d.len()); large_combination(d, k, move |result| { heap_permutation(&mut result.to_owned(), |r| cb(r)); }); } /// Similar to safe [k_permutation function](fn.k_permutation.html) except /// the way it return the permutation. /// It return result through mutable pointer to result assuming the /// pointer is valid. It'll notify caller on each new result via empty /// callback function. /// # Parameters /// - `d` A raw data to get k-permutation. /// - `k` A size of each permutation. /// - `result` A mutable pointer to slice of length equals to `k` /// - `cb` A callback function which will be called after new combination /// in `result` is set. /// # Return /// This function return result through function's parameter `result` and /// notify caller that new result is available through `cb` callback function. /// # Unsafe /// This function is unsafe because it may dereference a dangling pointer, /// may cause data race if multiple threads read/write to the same memory, /// and all of those unsafe Rust condition will be applied here. /// # Rationale /// The safe [k_permutation function](fn.k_permutation.html) return value in /// callback parameter. It limit the lifetime of return combination to be /// valid only inside it callback. To use it outside callback scope, it /// need to copy the value which will have performance penalty. Therefore, /// jeopardize it own goal of being fast. This function provide alternative /// way that sacrifice safety for performance. /// /// # Example /// The scenario is we want to get k-permutation from single source of data /// then distribute the permutation to two workers which read each permutation /// then do something about it, which in this example, simply print it. /// /// ``` /// use permutator::unsafe_k_permutation; /// use std::fmt::Debug; /// // define a trait that represent a data consumer /// trait Consumer { /// fn consume(&self); // cannot mut data because rule of no more than 1 ref mut at a time. /// } /// /// struct Worker1<'a, T : 'a> { /// data : &'a[&'a T] // A reference to each k-permutation /// } /// /// impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { /// fn consume(&self) { /// // Read data then do something about it. In this case, simply print it. /// println!("Work1 has {:?}", self.data); /// } /// } /// /// struct Worker2<'a, T : 'a> { /// data : &'a[&'a T] // A reference to each k-permutation /// } /// /// impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { /// fn consume(&self) { /// // Read data then do something about it. In this case, simply print it. /// println!("Work2 has {:?}", self.data); /// } /// } /// /// unsafe fn start_k_permutation_process<'a>(data : &'a[i32], cur_result : *mut [&'a i32], k : usize, consumers : Vec<Box<Consumer + 'a>>) { /// unsafe_k_permutation(data, k, cur_result, || { /// consumers.iter().for_each(|c| { /// c.consume(); /// }) /// }); /// } /// let k = 3; /// let data = &[1, 2, 3, 4, 5]; /// let mut result = vec![&data[0]; k]; /// /// unsafe { /// /// let shared = result.as_mut_slice() as *mut [&i32]; /// let worker1 = Worker1 { /// data : &result /// }; /// let worker2 = Worker2 { /// data : &result /// }; /// let consumers : Vec<Box<Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; /// start_k_permutation_process(data, shared, k, consumers); /// } /// ``` /// # Note /// Performancewise, k_permutation is faster than unsafe_k_permutation. /// The unsafe function is only faster when caller need to clone the result. /// # See /// - [k_permutation function](fn.k_permutation.html) pub unsafe fn unsafe_k_permutation<'a, T>(d : &'a [T], k : usize, result : *mut [&'a T], mut cb : impl FnMut() -> ()) { assert_eq!(k, (*result).len()); unsafe_large_combination(d, k, result, || { // save combination let buffer = (*result).to_owned(); // permute the combination in place heap_permutation(&mut *result, |_| { cb(); }); // restore combination so next combination is properly produce buffer.iter().enumerate().for_each(|(i, t)| (*result)[i] = *t) }); } /// Similar to safe [k_permutation function](fn.k_permutation.html) except /// the way it return the permutation. /// It return result through mutable pointer to result assuming the /// pointer is valid. It'll notify caller on each new result via empty /// callback function. /// # Parameters /// - `d` A raw data to get k-permutation. /// - `k` A size of each permutation. /// - `result` A mutable pointer to slice of length equals to `k` /// - `cb` A callback function which will be called after new combination /// in `result` is set. /// # Return /// This function return result through function's parameter `result` and /// notify caller that new result is available through `cb` callback function. /// # Rationale /// The safe [k_permutation function](fn.k_permutation.html) return value in /// callback parameter. It limit the lifetime of return combination to be /// valid only inside it callback. To use it outside callback scope, it /// need to copy the value which will have performance penalty. Therefore, /// jeopardize it own goal of being fast. This function provide alternative /// safe way to share the permutation with some minor performance cost. /// This function is about 50% slower than the unsafe counterpart. /// It's throughput is slightly slower than using a /// [next_into_cell](struct.KPermutationIterator.html#method.next_into_cell) by /// 15%-20% in uncontrol test environment. /// /// # Example /// The scenario is we want to get k-permutation from single source of data /// then distribute the combination to two workers which read each permutation /// then do something about it, which in this example, simply print it. /// /// ``` /// use permutator::k_permutation_cell; /// use std::fmt::Debug; /// use std::rc::Rc; /// use std::cell::RefCell; /// /// trait Consumer { /// fn consume(&self); /// } /// struct Worker1<'a, T : 'a> { /// data : Rc<RefCell<&'a mut[&'a T]>> /// } /// impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { /// fn consume(&self) { /// println!("Work1 has {:?}", self.data.borrow()); /// } /// } /// struct Worker2<'a, T : 'a> { /// data : Rc<RefCell<&'a mut[&'a T]>> /// } /// impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { /// fn consume(&self) { /// println!("Work2 has {:?}", self.data.borrow()); /// } /// } /// /// fn start_k_permutation_process<'a>(data : &'a[i32], cur_result : Rc<RefCell<&'a mut [&'a i32]>>, k : usize, consumers : Vec<Box<Consumer + 'a>>) { /// k_permutation_cell(data, k, cur_result, || { /// consumers.iter().for_each(|c| { /// c.consume(); /// }) /// }); /// } /// let k = 3; /// let data = &[1, 2, 3, 4, 5]; /// let mut result = vec![&data[0]; k]; /// let shared = Rc::new(RefCell::new(result.as_mut_slice())); /// /// let worker1 = Worker1 { /// data : Rc::clone(&shared) /// }; /// let worker2 = Worker2 { /// data : Rc::clone(&shared) /// }; /// let consumers : Vec<Box<Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; /// start_k_permutation_process(data, shared, k, consumers); /// ``` /// # Panic /// Panic if `k == 0` or `k > d.len()` /// /// # See /// - [k_permutation function](fn.k_permutation.html) pub fn k_permutation_cell<'a, T>(d : &'a [T], k : usize, result : Rc<RefCell<&'a mut [&'a T]>>, mut cb : impl FnMut() -> ()) { assert_ne!(k, 0); assert_eq!(k, result.borrow().len()); large_combination_cell(d, k, Rc::clone(&result), || { // save combination let origin = (*result).borrow().to_owned(); // permute the combination in place heap_permutation_cell(&result, || { cb(); }); // restore combination so next combination is properly produce origin.iter().enumerate().for_each(|(i, t)| result.borrow_mut()[i] = *t) }); } /// Similar to safe [k_permutation function](fn.k_permutation.html) except /// the way it return the permutation. /// It return result through mutable pointer to result assuming the /// pointer is valid. It'll notify caller on each new result via empty /// callback function. /// # Parameters /// - `d` A raw data to get k-permutation. /// - `k` A size of each permutation. /// - `result` A mutable pointer to slice of length equals to `k` /// - `cb` A callback function which will be called after new combination /// in `result` is set. /// # Return /// This function return result through function's parameter `result` and /// notify caller that new result is available through `cb` callback function. /// # Rationale /// The [k_permutation function](fn.k_permutation.html) return value in /// callback parameter. It limit the lifetime of return combination to be /// valid only inside it callback. To use it outside callback scope, it /// need to copy the value which will have performance penalty. Therefore, /// jeopardize it own goal of being fast. /// This function provide alternative way to share data between thread. /// It will write new result into Arc<RwLock<>> of Vec owned inside RwLock. /// Since it write data directly into Vec, other threads won't know that /// new data is wrote. The combination generator thread need to notify /// other threads via channel. This introduce another problem. /// Since combination generator write data directly into shared memory address, /// it need to know if all other threads are done using the data. /// Otherwise, in worst case, combination generator thread may dominate all other /// threads and hold write lock until it done generate every value. /// To solve such issue, combination generator thread need to get notified /// when each thread has done using the data. /// /// # Example /// The scenario is we want to get k-permutation from single source of data /// then distribute the combination to two workers which read each permutation /// then do something about it, which in this example, simply print it. /// /// ``` /// use permutator::k_permutation_sync; /// use std::sync::{Arc, RwLock}; /// use std::sync::mpsc; /// use std::sync::mpsc::{SyncSender, Receiver}; /// use std::thread; /// /// fn start_k_permutation_process<'a>(data : &'a[i32], cur_result : Arc<RwLock<Vec<&'a i32>>>, k : usize, notifier : Vec<SyncSender<Option<()>>>, release_recv : Receiver<()>) { /// use std::time::Instant; /// let timer = Instant::now(); /// let mut counter = 0; /// k_permutation_sync(data, k, cur_result, || { /// notifier.iter().for_each(|n| { /// n.send(Some(())).unwrap(); // notify every thread that new data available /// }); /// /// for _ in 0..notifier.len() { /// release_recv.recv().unwrap(); // block until all thread reading data notify on read completion /// } /// /// counter += 1; /// }); /// /// notifier.iter().for_each(|n| {n.send(None).unwrap()}); // notify every thread that there'll be no more data. /// /// println!("Done {} combinations with 2 workers in {:?}", counter, timer.elapsed()); /// } /// let k = 3; /// let data = &[1, 2, 3, 4, 5]; /// let result = vec![&data[0]; k]; /// let result_sync = Arc::new(RwLock::new(result)); /// /// // workter thread 1 /// let (t1_send, t1_recv) = mpsc::sync_channel::<Option<()>>(0); /// let (main_send, main_recv) = mpsc::sync_channel(0); /// let t1_local = main_send.clone(); /// let t1_dat = Arc::clone(&result_sync); /// thread::spawn(move || { /// while let Some(_) = t1_recv.recv().unwrap() { /// let result : &Vec<&i32> = &*t1_dat.read().unwrap(); /// println!("Thread1: {:?}", result); /// t1_local.send(()).unwrap(); // notify generator thread that reference is no longer neeed. /// } /// println!("Thread1 is done"); /// }); /// /// // worker thread 2 /// let (t2_send, t2_recv) = mpsc::sync_channel::<Option<()>>(0); /// let t2_dat = Arc::clone(&result_sync); /// let t2_local = main_send.clone(); /// thread::spawn(move || { /// while let Some(_) = t2_recv.recv().unwrap() { /// let result : &Vec<&i32> = &*t2_dat.read().unwrap(); /// println!("Thread2: {:?}", result); /// t2_local.send(()).unwrap(); // notify generator thread that reference is no longer neeed. /// } /// println!("Thread2 is done"); /// }); /// /// // main thread that generate result /// thread::spawn(move || { /// start_k_permutation_process(data, result_sync, k, vec![t1_send, t2_send], main_recv); /// }).join().unwrap(); /// ``` /// # See /// - [k_permutation function](fn.k_permutation.html) pub fn k_permutation_sync<'a, T>(d : &'a [T], k : usize, result : Arc<RwLock<Vec<&'a T>>>, mut cb : impl FnMut() -> ()) { assert_ne!(k, 0); assert_eq!(k, result.read().unwrap().len()); large_combination_sync(d, k, Arc::clone(&result), || { // save combination let origin = (*result).read().unwrap().to_owned(); // permute the combination in place heap_permutation_sync(&result, || { cb(); }); // restore combination so next combination is properly produce origin.iter().enumerate().for_each(|(i, t)| result.write().unwrap()[i] = *t) }); } /// A lexicographic ordered permutation based on ["Algoritm X" published by /// Donald E. Knuth.](http://www.cs.utsa.edu/~wagner/knuth/fasc2b.pdf) page 20. /// The sample implementation in C++ can be found in [Kevin Lynch /// repository.](https://gist.github.com/klynch/807973/cf05e785a68a5ae8b6a3381752583b97186f6140) /// He implemented Algorithm X in an structured iterator style. /// The discussion on how to implement "Algorithm X" in structured fashion in /// discussed [here](https://stackoverflow.com/questions/37079307/untying-knuths-knots-how-to-restructure-spaghetti-code) /// The implementation here is inspired by the post from stackoverflow. /// /// # Parameters /// - d : &[T] - a data to be permuted /// - result_fn : FnMut(usize, usize) - Function/Closure that responsible for /// assign a data into result container. The first parameter is an index of result /// to be re-assigned. The second parameter is an index of data to be assigned to result. /// - t : FnMut(usize) -> bool - a function defined by "Algorithm X" that get called /// by current "prefix" to check if such "prefix" need to be kept. If true, the /// "prefix" will be kept. If false, the entire sub-tree with this "prefix" will be skip. /// The parameter will be usize which is max bound of current result. The "prefix" /// therefore shall be a subslice of range 0 till given parameter. For example, /// result[0..k] /// - cb : FnMut() - Callback function that shall return result to caller fn _x_permutation_core<T>(d : &[T], mut result_fn : impl FnMut(usize, usize), mut t : impl FnMut(usize) -> bool, mut cb : impl FnMut()) { /// Return tuple of (a, k, l, n) where /// - a is a Vec<usize>, array holding index of permuted. /// - k is usize and l is Vec<usize> /// Init value is k = 1 /// - l is a Vec<usize> /// Init l[k] = k + 1 where 0 <= k < n /// l[n] = 0 /// - n is usize, a length of data /// - perm is Vec<&T>, holding permuted value /// - u is Vec<usize>, holding undo vec #[inline(always)] fn init<T>(d : &[T]) -> (Vec<usize>, usize, Vec<usize>, usize, Vec<usize>) { // l[k] = k + 1 where 0 <= k < n let mut l : Vec<usize> = (0..d.len()).map(|k| k + 1).collect(); let a : Vec<usize> = (0..=d.len()).map(|v| v).collect(); let n = d.len(); let u = vec![0; n + 1]; // l[n] = 0 l.push(0); let k = 1; (a, k, l, n, u) }; /// Return tuple of (p, q) where /// p = 0 and q = l[0] #[inline(always)] fn enter(l : &[usize]) -> (usize, usize) { return (0, l[0]) } // "Algo X" X1 let (mut a, mut k, mut l, n, mut u) = init(d); // "Algo X" X2 let (mut p, mut q) = enter(&l); loop { // "Algo X" X3 // perm[k - 1] = &d[q - 1]; result_fn(k - 1, q - 1); a[k] = q; if t(k) { // part of "Algo X" X3 if k == n { // part of "Algo X" X3 cb(); // visit part of "Algo X" X3 loop { // condition of "Algo X" X5 // "Algo X" X6 k -= 1; if k == 0 { return; } else { p = u[k]; q = a[k]; l[p] = q; // "Algo X" X5 p = q; q = l[p]; if q != 0 { break; } } } } else { // "Algo X" X4 u[k] = p; l[p] = l[q]; k += 1; // "Algo X" X2 let (new_p, new_q) = enter(&l); p = new_p; q = new_q; } } else { // "Algo X" X5 loop { p = q; q = l[p]; if q != 0 { break; } // "Algo X" X6 k -= 1; if k == 0 { return; } else { p = u[k]; q = a[k]; l[p] = q; } } } } } /// A lexicographic ordered permutation based on ["Algoritm X" published by /// Donald E. Knuth.](http://www.cs.utsa.edu/~wagner/knuth/fasc2b.pdf) page 20. /// /// If order is not important, consider using [heap permutation](fn.heap_permutation.html) /// function instead. This function is 3 times slower than [heap /// permutation](fn.heap_permutation.html) in uncontroll test environment. /// /// The algorithm work by simulate tree traversal where some branch can be /// skip altogether. This is archive by provided `t` function that take /// slice of partial result as parameter. If the partial result needed to be skip, /// return false. Otherwise, return true and the algorithm will call this function /// again when the branch is descended deeper. For example: First call to `t` may /// contain [1]. If `t` return true, it will be called again with [1, 2]. If it /// return true, and there's leaf node, cb will be called with [1, 2]. On the other hand, /// if `t` is called with [1, 3] and it return false, it won't call the callback. /// If `t` is called with [4] and it return false, it won't try to traverse deeper even /// if there're [4, 5], or [4, 6]. It will skip altogether and call `t` with [7]. /// The process goes on until every branch is traversed. /// /// # Example /// Get all lexicalgraphic ordered permutation /// ```Rust /// use permutator::x_permutation; /// /// let data = vec![1, 2, 3, 4]; /// let mut counter = 0; /// /// x_permutation(&data, |_| true, |p| { /// println!("{:?}", p); /// counter += 1; /// }); /// /// assert_eq!(factorial(data.len()), counter); /// ``` /// Skip all permutation that has `1` in first element. /// ```Rust /// use permutator::x_permutation; /// /// let data : Vec<u8> = vec![1, 2, 3, 4]; /// let mut counter = 0; /// /// x_permutation(&data, |f| { /// *f[0] != 1u8 // filter all permutation that start with 1 /// }, |p| { /// println!("{:?}", p); /// counter += 1; /// }); /// /// assert_eq!(factorial(data.len()) - factorial(data.len() - 1), counter); /// ``` /// Multi-threads permutation example /// ```Rust /// use std::sync::{Arc, RwLock}; /// use permutator::{get_permutation_for, x_permutation}; /// /// let mut data : Vec<u8> = (0..5u8).map(|v| v).collect(); /// let threads = 2usize; /// let chunk = data.len() / threads; // split data into 3 threads. /// let complete_count = Arc::new(RwLock::new(0u64)); /// let total_counter = Arc::new(RwLock::new(0u64)); /// for i in 0..threads { /// let u_bound = match i { /// j if j == threads - 1 => data.len() as u8, // last thread do all the rest /// _ => (chunk * (i + 1)) as u8 /// }; /// let l_bound = (chunk * i) as u8; /// let perm = get_permutation_for(&data, data.len(), l_bound as usize).unwrap(); /// let t_dat : Vec<u8> = perm.iter().map(|v| **v).collect(); // need to move to each thread /// let t_counter = Arc::clone(&complete_count); // thread completed count /// let loc_counter = Arc::clone(&total_counter); // count number of permutation /// thread::spawn(move || { /// let mut counter = 0u64; /// x_permutation(&t_dat, |v| { /// *v[0] >= l_bound && *v[0] < u_bound /// }, |_p| { /// counter += 1; /// }); /// /// *loc_counter.write().unwrap() += counter; /// println!("Done {} in local thread", counter); /// *t_counter.write().unwrap() += 1; /// }); /// } /// /// let main = thread::spawn(move || { /// let timer = Instant::now(); /// loop { /// if *complete_count.read().unwrap() != (threads as u64) { /// thread::sleep(Duration::from_millis(100)); /// } else { /// println!("Done {} x_permutation {} threads in {:?}", &*total_counter.read().unwrap(), threads, timer.elapsed()); /// break; /// } /// } /// }); /// /// main.join().unwrap(); /// ``` /// /// # Parameters /// - d : &[T] - A data to get a permutation. /// - t : FnMut(&[&T]) -> bool - A function for checking whether to traverse the branch. /// It shall return true if the branch need to be traversed. /// - cb : FnMut(&[&T]) - A callback function that return result to caller. pub fn x_permutation<T>(d : &[T], mut t : impl FnMut(&[&T]) -> bool, mut cb : impl FnMut(&[&T])) { let mut perm : Vec<&T> = (0..d.len()).map(|i| &d[i]).collect(); let perm_ptr = &perm as *const Vec<&T>; _x_permutation_core( d, |i, j| { perm[i] = &d[j]; }, |k| -> bool { unsafe { // should be safe as it got called after it mutated t(&(*perm_ptr)[0..k]) } }, || { // should be safe as it got called after it mutated unsafe { cb(&(*perm_ptr)) } } ) } /// A lexicographic ordered permutation based on ["Algoritm X" published by /// Donald E. Knuth.](http://www.cs.utsa.edu/~wagner/knuth/fasc2b.pdf) page 20. /// /// If order is not important, consider using [heap permutation](fn.heap_permutation_cell.html) /// function instead. This function is 3 times slower than heap [heap /// permutation](fn.heap_permutation_cell.html) in uncontroll test environment. /// /// The algorithm work by simulate tree traversal where some branch can be /// skip altogether. This is archive by provided `t` function that take /// slice of partial result as parameter. If the partial result needed to be skip, /// return false. Otherwise, return true and the algorithm will call this function /// again when the branch is descended deeper. For example: First call to `t` may /// contain [1]. If `t` return true, it will be called again with [1, 2]. If it /// return true, and there's leaf node, cb will be called with [1, 2]. On the other hand, /// if `t` is called with [1, 3] and it return false, it won't call the callback. /// If `t` is called with [4] and it return false, it won't try to traverse deeper even /// if there're [4, 5], or [4, 6]. It will skip altogether and call `t` with [7]. /// The process goes on until every branch is traversed. /// /// # Example /// See [x_permutation document](fn.x_permutation.html) for example. /// It's the same except the way it return result. /// /// # Parameters /// - d : &[T] - A data to get a permutation. /// - result : Rc<RefCell<&mut [&T]>> - A result container. /// The result will be overwritten on each call to callback. /// - t : FnMut(&[&T]) -> bool - A function for checking whether to traverse the branch. /// It shall return true if the branch need to be traversed. /// - cb : FnMut() - A callback function that notify caller that new result is available. pub fn x_permutation_cell<'a, T>(d : &'a [T], result : Rc<RefCell<&mut [&'a T]>>,mut t : impl FnMut(&[&T]) -> bool, mut cb : impl FnMut()) { assert_eq!(result.borrow().len(), d.len(), "`result` shall has length equals to `d`"); { // init result let mut mutable_res = result.borrow_mut(); (0..d.len()).for_each(|i| mutable_res[i] = &d[i]); } _x_permutation_core( d, |i, j| { result.borrow_mut()[i] = &d[j]; }, |k| -> bool { t(&result.borrow()[0..k]) }, || { // should be safe as it got called after it mutated cb() } ) } /// A lexicographic ordered permutation based on ["Algoritm X" published by /// Donald E. Knuth.](http://www.cs.utsa.edu/~wagner/knuth/fasc2b.pdf) page 20. /// /// If order is not important, consider using [heap permutation](fn.heap_permutation_sync.html) /// function instead. This function is 3 times slower than heap [heap /// permutation](fn.heap_permutation_sync.html) in uncontroll test environment. /// /// The algorithm work by simulate tree traversal where some branch can be /// skip altogether. This is archive by provided `t` function that take /// slice of partial result as parameter. If the partial result needed to be skip, /// return false. Otherwise, return true and the algorithm will call this function /// again when the branch is descended deeper. For example: First call to `t` may /// contain [1]. If `t` return true, it will be called again with [1, 2]. If it /// return true, and there's leaf node, cb will be called with [1, 2]. On the other hand, /// if `t` is called with [1, 3] and it return false, it won't call the callback. /// If `t` is called with [4] and it return false, it won't try to traverse deeper even /// if there're [4, 5], or [4, 6]. It will skip altogether and call `t` with [7]. /// The process goes on until every branch is traversed. /// /// # Example /// See [x_permutation document](fn.x_permutation.html) for example. /// It's the same except the way it return result. /// /// # Parameters /// - d : &[T] - A data to get a permutation. /// - result : Arc<RwLock<Vec<&T>>> - A result container. /// The result will be overwritten on each call to callback. /// - t : FnMut(&[&T]) -> bool - A function for checking whether to traverse the branch. /// It shall return true if the branch need to be traversed. /// - cb : FnMut() - A callback function that notify caller that new result is available. pub fn x_permutation_sync<'a, T>(d : &'a [T], result : Arc<RwLock<Vec<&'a T>>>,mut t : impl FnMut(&[&T]) -> bool, mut cb : impl FnMut()) { assert_eq!(result.read().unwrap().len(), d.len(), "`result` shall has length equals to `d`"); { // init result let mut mutable_res = result.write().unwrap(); (0..d.len()).for_each(|i| mutable_res[i] = &d[i]); } _x_permutation_core( d, |i, j| { result.write().unwrap()[i] = &d[j]; }, |k| -> bool { t(&result.read().unwrap()[0..k]) }, || { // should be safe as it got called after it mutated cb() } ) } /// A lexicographic ordered permutation based on ["Algoritm X" published by /// Donald E. Knuth.](http://www.cs.utsa.edu/~wagner/knuth/fasc2b.pdf) page 20. /// /// If order is not important, consider using [heap permutation](fn.unsafe_heap_permutation.html) /// function instead. This function is 3 times slower than heap [heap /// permutation](fn.unsafe_heap_permutation.html) in uncontroll test environment. /// /// The algorithm work by simulate tree traversal where some branch can be /// skip altogether. This is archive by provided `t` function that take /// slice of partial result as parameter. If the partial result needed to be skip, /// return false. Otherwise, return true and the algorithm will call this function /// again when the branch is descended deeper. For example: First call to `t` may /// contain [1]. If `t` return true, it will be called again with [1, 2]. If it /// return true, and there's leaf node, cb will be called with [1, 2]. On the other hand, /// if `t` is called with [1, 3] and it return false, it won't call the callback. /// If `t` is called with [4] and it return false, it won't try to traverse deeper even /// if there're [4, 5], or [4, 6]. It will skip altogether and call `t` with [7]. /// The process goes on until every branch is traversed. /// /// # Example /// See [x_permutation document](fn.x_permutation.html) for example. /// It's the same except the way it return result. /// /// # Parameters /// - d : &[T] - A data to get a permutation. /// - result : *mut [&T] - A result container. /// The result will be overwritten on each call to callback. /// - t : FnMut(&[&T]) -> bool - A function for checking whether to traverse the branch. /// It shall return true if the branch need to be traversed. /// - cb : FnMut() - A callback function that notify caller that new result is available. /// /// # Safety /// This function is unsafe to used. This function store result into raw pointer thus all /// unsafe Rust condition may applied. For example, it may seg fault if pointer is invalid. /// It may cause datarace. It may leak memory. /// /// # Rationale /// This function permit sharing data to other without cost by sacrifice the safety. /// For safely share result in single thread, consider using /// [x_permutation_cell](fn.x_permutation_cell.html). For safely share result in /// multi-threads, consider using [x_permutation_sync](fn.x_permutation_sync.html). /// Both functions have some cost due to additional safety check. pub unsafe fn unsafe_x_permutation<'a, T>(d : &'a [T], result : *mut [&'a T], mut t : impl FnMut(&[&T]) -> bool, mut cb : impl FnMut()) { assert_eq!((*result).len(), d.len(), "`result` shall has length equals to `d`"); (0..d.len()).for_each(|i| (*result)[i] = &d[i]); _x_permutation_core( d, |i, j| { (*result)[i] = &d[j]; }, |k| -> bool { t(&(*result)[0..k]) }, || { // should be safe as it got called after it mutated cb() } ) } /// A trait that add reset function to an existing Iterator. /// It mean that the `next` or `next_into_cell` call will start returning /// the first element again pub trait IteratorReset { /// Reset an iterator. It make an iterator start from the beginning again. fn reset(&mut self); } /// Core algorithm of `next` function for all `CartesianProduct` iterator /// family. /// /// # Parameters /// 1. `i` - ref mut usize which is cursor pointed to domain inside domains /// 2. `c` - ref mut Vec of usize which is cursor of each domain /// 3. `exhausted` - boolean which if true mean iterator is exhausted /// 4. `n` - number of domains /// 5. `domain_len` - is a closure that take usize and return size of /// the domain at given usize #[inline(always)] fn _cartesian_next_core<'a>( i : &mut usize, c : &mut Vec<usize>, exhausted : &mut bool, n : usize, domain_len : impl Fn(usize) -> usize, mut into_result : impl FnMut(usize, usize) + 'a) { // move and set `result` and `c` up until all `domains` processed while *i < n && ! *exhausted { // if current domain is exhausted. if c[*i] == domain_len(*i) { // reset all exhausted domain in `result` and `c` let mut k = *i; // reset all exhausted until either found non-exhausted or reach first domain while c[k] == domain_len(k) && k > 0 { c[k] = 1; into_result(k, 0); k -= 1; } if k == 0 && c[k] == domain_len(k) { // if first domain is also exhausted then flag it. *exhausted = true; } else { // otherwise advance c[k] and set result[k] to next value // self.result[k] = &self.domains[k][self.c[k]]; into_result(k, c[k]); c[k] += 1; } } else { // non exhausted domain, advance `c` and set result // self.result[self.i] = &self.domains[self.i][self.c[self.i]]; into_result(*i, c[*i]); c[*i] += 1; } *i += 1; } } /// Generate a cartesian product between given domains in an iterator style. /// The struct implement `Iterator` trait so it can be used in `Iterator` /// style. The struct provide [into_iter()](#method.into_iter()) function /// that return itself. /// /// # Example /// ``` /// use permutator::CartesianProductIterator; /// use std::time::Instant; /// let data : &[&[usize]] = &[&[1, 2, 3], &[4, 5, 6], &[7, 8, 9]]; /// let cart = CartesianProductIterator::new(&data); /// let mut counter = 0; /// let timer = Instant::now(); /// /// for p in cart { /// // println!("{:?}", p); /// counter += 1; /// } /// /// // or functional style like the line below /// // cart.into_iter().for_each(|p| {/* do something iterative style */}); /// /// assert_eq!(data.iter().fold(1, |cum, domain| {cum * domain.len()}), counter); /// println!("Total {} products done in {:?}", counter, timer.elapsed()); /// ``` pub struct CartesianProductIterator<'a, T> where T : 'a { c : Vec<usize>, domains : &'a [&'a [T]], exhausted : bool, i : usize, result : Vec<&'a T> } impl<'a, T> CartesianProductIterator<'a, T> where T : 'a { /// Create a new Cartesian product iterator that create a product between /// each domain inside `domains`. /// # Parameters /// - `domains` A slice of domains to create a cartesian product between /// each domain inside it. /// # Return /// An object that can be iterate over in iterator style. pub fn new(domains : &'a[&[T]]) -> CartesianProductIterator<'a, T> { CartesianProductIterator { c : vec![0; domains.len()], domains : domains, exhausted : false, i : 0, result : vec![&domains[0][0]; domains.len()] } } /// Consume itself and return without modify it. /// Typical usecase is `for p in ref_to_this.into_iter() {}` /// or `ref_to_this.into_iter().for_each(|p| {/* Do something with product */});` pub fn into_iter(self) -> Self { self } } impl<'a, T> Iterator for CartesianProductIterator<'a, T> { type Item = Vec<&'a T>; /// Each iteration return a new Vec contains borrowed element inside /// an Option. The result can be collected by using `collect` method /// from `Iterator` trait. /// /// Return None when exhausted. fn next(&mut self) -> Option<Vec<&'a T>> { let domains = self.domains; let result = &mut self.result; _cartesian_next_core( &mut self.i, &mut self.c, &mut self.exhausted, domains.len(), #[inline(always)] |k| { domains[k].len() }, #[inline(always)] |i, j| { result[i] = &domains[i][j]; } ); if self.exhausted { None } else { self.i -= 1; // rewind `i` back to last domain Some(result.to_owned()) } } } impl<'a, T> IteratorReset for CartesianProductIterator<'a, T> { fn reset(&mut self) { self.c = vec![0; self.domains.len()]; self.exhausted = false; self.i = 0; } } impl<'a, T> ExactSizeIterator for CartesianProductIterator<'a, T> { fn len(&self) -> usize { self.domains.iter().fold(1, |cum, d| {cum * d.len()}) } } /// Generate a cartesian product between given domains into Rc<RefCell<&mut [&T]>> /// in an iterator style. /// The struct implement `Iterator` trait so it can be used as `Iterator`. /// The struct provide [into_iter()](#method.into_iter()) function /// that return itself. /// /// # Example /// - Iterator style usage /// ``` /// use permutator::CartesianProductCellIter; /// use std::cell::RefCell; /// use std::rc::Rc; /// use std::time::Instant; /// let data : Vec<&[usize]> = vec![&[1, 2, 3], &[4, 5, 6], &[7, 8, 9]]; /// let mut result : Vec<&usize> = vec![&data[0][0]; data.len()]; /// let shared = Rc::new(RefCell::new(result.as_mut_slice())); /// let cart = CartesianProductCellIter::new(&data, Rc::clone(&shared)); /// let mut counter = 0; /// let timer = Instant::now(); /// /// for _ in cart { /// println!("{:?}", &*shared.borrow()); /// counter += 1; /// } /// /// // or functional style like the line below /// // cart.into_iter().for_each(|_| {/* do something iterative style */}); /// /// assert_eq!(data.iter().fold(1, |cum, domain| {cum * domain.len()}), counter); /// println!("Total {} products done in {:?}", counter, timer.elapsed()); /// ``` pub struct CartesianProductCellIter<'a, T> where T : 'a { c : Vec<usize>, domains : &'a [&'a [T]], exhausted : bool, i : usize, result : Rc<RefCell<&'a mut [&'a T]>> } impl<'a, T> CartesianProductCellIter<'a, T> { pub fn new(data : &'a [&'a [T]], result : Rc<RefCell<&'a mut [&'a T]>>) -> CartesianProductCellIter<'a, T> { CartesianProductCellIter { c : vec![0; data.len()], domains : data, exhausted : false, i : 0, result : result } } pub fn into_iter(self) -> Self { self } } impl<'a, T> Iterator for CartesianProductCellIter<'a, T> where T : 'a { type Item = (); /// Mimic iterator `next` function but return value into Rc<RefCell<>> that /// contains mutable slice. It also return an empty Option to tell caller /// to distinguish if it's put new value or the iterator itself is exhausted. /// # Paramerter /// - `result` An Rc<RefCell<>> contains a mutable slice with length equals /// to number of `domains` given in [CartesianProductIterator::new()](struct.CartesianProductIterator.html#method.new). /// The value inside result will be updated everytime this function is called /// until the function return None. The performance using this function is /// on part with [cartesian_cell function](fn.cartesian_product_cell.html) on uncontrol /// test environment. /// # Return /// New cartesian product between each `domains` inside `result` parameter /// and also return `Some(())` if result is updated or `None` when there's /// no new result. fn next(&mut self) -> Option<()> { let mut result = self.result.borrow_mut(); let domains = self.domains; _cartesian_next_core( &mut self.i, &mut self.c, &mut self.exhausted, domains.len(), #[inline(always)] |k| { domains[k].len() }, #[inline(always)] |i, j| { result[i] = &domains[i][j]; } ); if self.exhausted { None } else { self.i -= 1; // rewind `i` back to last domain Some(()) } } } impl<'a, T> IteratorReset for CartesianProductCellIter<'a, T> { fn reset(&mut self) { self.c.iter_mut().for_each(|c| {*c = 0}); self.exhausted = false; self.i = 0; } } impl<'a, T> ExactSizeIterator for CartesianProductCellIter<'a, T> { fn len(&self) -> usize { self.domains.iter().fold(1, |cum, d| {cum * d.len()}) } } /// An unsafe way to generate a cartesian product between given domains /// into *mut [&T] in an iterator style. /// The struct implement `Iterator` trait so it can be used as `Iterator`. /// The struct provide [into_iter()](#method.into_iter()) function /// that return itself. /// /// # Unsafe /// It took mutable pointer to slice in /// [object instantiation](struct.CartesianProductRefIter.html#method.new) /// and convert it upon creation into mutable borrowed slice. /// All unsafe Rust conditions, therefore, applied to entire usage /// of this struct. /// /// # Rationale /// It uses unsafe to take a mutable pointer to store the result /// to avoid the cost of using Rc<RefCell<>>. /// In uncontroll test environment, this struct perform a complete /// iteration over 12,960 products in about 110ms where /// [CartesianProductCellIter](struct.CartesianProductCellIter.html) /// took about 130ms. /// This function is very much alike /// [unsafe_cartesian_product function](fn.unsafe_cartesian_product.html) /// but took `Iterator` approach. /// /// # Example /// - Iterator style usage /// ``` /// use permutator::CartesianProductRefIter; /// use std::time::Instant; /// let data : Vec<&[usize]> = vec![&[1, 2, 3], &[4, 5, 6], &[7, 8, 9]]; /// let mut result : Vec<&usize> = vec![&data[0][0]; data.len()]; /// unsafe { /// let cart = CartesianProductRefIter::new(&data, result.as_mut_slice() as *mut [&usize]); /// let mut counter = 0; /// let timer = Instant::now(); /// /// for _ in cart { /// println!("{:?}", result); /// counter += 1; /// } /// /// // or functional style like the line below /// // cart.into_iter().for_each(|_| {/* do something iterative style */}); /// /// assert_eq!(data.iter().fold(1, |cum, domain| {cum * domain.len()}), counter); /// println!("Total {} products done in {:?}", counter, timer.elapsed()); /// } /// ``` pub struct CartesianProductRefIter<'a, T> where T : 'a { c : Vec<usize>, domains : &'a [&'a [T]], exhausted : bool, i : usize, result : &'a mut [&'a T] } impl<'a, T> CartesianProductRefIter<'a, T> { /// Create an iterator with mutable pointer to store the product. /// It is unsafe because it convert mutable pointer into mutable borrowed value /// upon creating the object. /// /// # Parameter /// - `data` a borrowed slice contains borrowed slices. It's /// domains of cartesian product operation. /// - `result` a mutable pointer pointed to the slice that /// will be used to store the cartesian product result. /// The length of the slice shall equals to len of data. /// /// # Return /// Each iteration return empty Option and store actual result into /// `result` given when construct this `Iterator`. pub unsafe fn new(data : &'a [&'a [T]], result : *mut [&'a T]) -> CartesianProductRefIter<'a, T> { CartesianProductRefIter { c : vec![0; data.len()], domains : data, exhausted : false, i : 0, result : &mut *result } } pub fn into_iter(self) -> Self { self } } impl<'a, T> Iterator for CartesianProductRefIter<'a, T> where T : 'a { type Item = (); /// Mimic iterator `next` function but return value into Rc<RefCell<>> that /// contains mutable slice. It also return an empty Option to tell caller /// to distinguish if it's put new value or the iterator itself is exhausted. /// # Paramerter /// - `result` An Rc<RefCell<>> contains a mutable slice with length equals /// to number of `domains` given in [CartesianProductIterator::new()](struct.CartesianProductIterator.html#method.new). /// The value inside result will be updated everytime this function is called /// until the function return None. The performance using this function is /// on part with [cartesian_cell function](fn.cartesian_product_cell.html) on uncontrol /// test environment. /// # Return /// New cartesian product between each `domains` inside `result` parameter /// and also return `Some(())` if result is updated or `None` when there's /// no new result. fn next(&mut self) -> Option<()> { let result = &mut self.result; let domains = self.domains; _cartesian_next_core( &mut self.i, &mut self.c, &mut self.exhausted, domains.len(), #[inline(always)] |k| { domains[k].len() }, #[inline(always)] |i, j| { result[i] = &domains[i][j]; } ); if self.exhausted { None } else { self.i -= 1; // rewind `i` back to last domain Some(()) } } } impl<'a, T> IteratorReset for CartesianProductRefIter<'a, T> { fn reset(&mut self) { self.c.iter_mut().for_each(|c| {*c = 0}); self.exhausted = false; self.i = 0; } } impl<'a, T> ExactSizeIterator for CartesianProductRefIter<'a, T> { fn len(&self) -> usize { self.domains.iter().fold(1, |cum, d| {cum * d.len()}) } } /// A core logic of `next` function of `GosperCombination` iterator family. /// /// # Parameters /// 1. `map` - a ref mut pointed to gosper map /// 2. `into_result` - closure that take two usizes. First usize is /// incremented on each call by 1. Second usize is index of which /// data that is mapped by gosper's map. #[inline(always)] fn _gosper_next_core(map : &mut u128, mut into_result : impl FnMut(usize, usize)) { let mut i = 0; let mut j = 0; let mut mask = *map; while mask > 0 { if mask & 1 == 1 { into_result(i, j); i += 1; } mask >>= 1; j += 1; } stanford_combination(map); } /// # Deprecated /// This iterator family is now deprecated. /// Consider using [LargeCombinationIterator](struct.LargeCombinationIterator.html) /// instead. This is because current implementation need to copy every ref /// on every iteration which is inefficient. /// On uncontroll test environment, this iterator take 18.98s to iterate over /// 30,045,015 combinations. The [LargeCombinationIterator](struct.LargeCombinationIterator.html) /// took only 2.77s. /// If no more efficient implementation is available for some certain time period, /// this function will be officially mark with #[deprecated]. /// /// Create a combination iterator. /// It use Gosper's algorithm to pick a combination out of /// given data. The produced combination provide no lexicographic /// order. /// /// The returned combination will be a reference into given data. /// Each combination return from iterator will be a new Vec. /// It's safe to hold onto a combination or `collect` it. /// /// # Examples /// Given slice of [1, 2, 3, 4, 5]. It will produce following /// combinations: /// [1, 2, 3], [1, 2, 4], [1, 3, 4], [2, 3, 4], [1, 2, 5], /// [1, 3, 5], [2, 3, 5], [1, 4, 5], [2, 4, 5], [3, 4, 5] /// Here's an example of code printing above combination. /// ``` /// use permutator::GosperCombinationIterator; /// use std::time::{Instant}; /// let gosper = GosperCombinationIterator::new(&[1, 2, 3, 4, 5], 3); /// let mut counter = 0; /// let timer = Instant::now(); /// /// for combination in gosper { /// println!("{}:{:?}", counter, combination); /// counter += 1; /// } /// /// println!("Total {} combinations in {:?}", counter, timer.elapsed()); /// ``` /// # Limitation /// Gosper algorithm need to know the MSB (most significant bit). /// The current largest known MSB data type is u128. /// This make the implementation support up to 128 elements slice. /// /// # See /// - [Gospel's algorithm in Wikipedia page, October 9, 2018](https://en.wikipedia.org/wiki/Combinatorial_number_system#Applications) pub struct GosperCombinationIterator<'a, T> where T : 'a { data : &'a [T], // data to generate a combination len : usize, // total possible number of combination. r : usize, // a size of combination. x : u128, // A binary map to generate combination } impl<'a, T> GosperCombinationIterator<'a, T> { /// Create new combination generator using Gosper's algorithm. /// `r` shall be smaller than data.len(). /// /// Note: It perform no check on given parameter. /// If r is larger than length of data then iterate over it /// will not occur. The iteration will be end upon enter. pub fn new(data : &[T], r : usize) -> GosperCombinationIterator<T> { let mut x : u128 = 1; x <<= r; x -= 1; let n = data.len(); GosperCombinationIterator { data : data, len : divide_factorial(n, multiply_factorial(n - r, r)), r : r, x : x } } /// Total number of combinations this iterate can return. /// It will equals to n!/((n-r)!*r!) pub fn len(&self) -> usize { self.len } pub fn reset(&mut self) { self.x = 1; self.x <<= self.r; self.x -= 1; } } impl<'a, T> IntoIterator for GosperCombinationIterator<'a, T> { type Item = Vec<&'a T>; type IntoIter = CombinationIterator<'a, T>; fn into_iter(self) -> CombinationIterator<'a, T> { CombinationIterator { data : self.data, r : self.r, x : self.x } } } /// # Deprecated /// /// An iterator return from [struct GosperCombination](struct.GosperCombinationIterator.html) /// or from [trait Combination](trait.Combination.html) over slice or vec of data. pub struct CombinationIterator<'a, T> where T : 'a { data : &'a [T], // original data r : usize, // len of each combination x : u128, // Gosper binary map } impl<'a, T> Iterator for CombinationIterator<'a, T> { type Item = Vec<&'a T>; fn next(&mut self) -> Option<Vec<&'a T>> { let mut combination : Vec<&T> = Vec::new(); if 128 - self.x.leading_zeros() as usize > self.data.len() { return None } // stanford_combination(&mut self.x); let data = self.data; let map = &mut self.x; _gosper_next_core(map, #[inline(always)] |_, j| { combination.push(&data[j]); } ); return Some(combination) } } impl<'a, T> IteratorReset for CombinationIterator<'a, T> { fn reset(&mut self) { self.x = 1; self.x <<= self.r; self.x -= 1; } } impl<'a, T> ExactSizeIterator for CombinationIterator<'a, T> { fn len(&self) -> usize { let n = self.data.len(); divide_factorial(n, multiply_factorial(n - self.r, self.r)) } } /// # Deprecated /// This iterator family is now deprecated. /// Consider using [LargeCombinationCellIter](struct.LargeCombinationCellIter.html) /// instead. This is because current implementation need to copy every ref /// on every iteration which is inefficient. /// On uncontroll test environment, this iterator take 2.49s to iterate over /// 30,045,015 combinations. The [LargeCombinationCellIter](struct.LargeCombinationCellIter.html) /// took only 446.39ms. /// /// Create a combination iterator. /// It use Gosper's algorithm to pick a combination out of /// given data. The produced combination provide no lexicographic /// order. /// /// The returned combination will be a reference into given data. /// Each combination return from iterator by storing into given /// Rc<RefCell<&mut [&T]>> along with empty Option. /// /// # Examples /// Given slice of [1, 2, 3, 4, 5]. It will produce following /// combinations: /// [1, 2, 3], [1, 2, 4], [1, 3, 4], [2, 3, 4], [1, 2, 5], /// [1, 3, 5], [2, 3, 5], [1, 4, 5], [2, 4, 5], [3, 4, 5] /// Here's an example of code printing above combination. /// ``` /// use permutator::{GosperCombinationCellIter}; /// use std::cell::RefCell; /// use std::rc::Rc; /// use std::time::{Instant}; /// let data = &[1, 2, 3, 4, 5]; /// let mut result : &mut[&i32] = &mut [&data[0]; 3]; /// let shared = Rc::new(RefCell::new(result)); /// let mut gosper = GosperCombinationCellIter::new(&[1, 2, 3, 4, 5], 3, Rc::clone(&shared)); /// let mut counter = 0; /// let timer = Instant::now(); /// /// for _ in gosper { /// println!("{}:{:?}", counter, shared); /// counter += 1; /// } /// /// println!("Total {} combinations in {:?}", counter, timer.elapsed()); /// ``` /// /// # Limitation /// Gosper algorithm need to know the MSB (most significant bit). /// The current largest known MSB data type is u128. /// This make the implementation support up to 128 elements slice. /// /// # See /// - [Gospel's algorithm in Wikipedia page, October 9, 2018](https://en.wikipedia.org/wiki/Combinatorial_number_system#Applications) pub struct GosperCombinationCellIter<'a, T> where T : 'a { data : &'a [T], // data to generate a combination len : usize, // total possible number of combination. r : usize, // a size of combination. x : u128, // A binary map to generate combination result : Rc<RefCell<&'a mut [&'a T]>> } impl<'a, T> GosperCombinationCellIter<'a, T> { /// Create new combination generator using Gosper's algorithm. /// `r` shall be smaller than data.len(). /// /// Note: It perform no check on given parameter. /// If r is larger than length of data then iterate over it /// will not occur. The iteration will be end upon enter. pub fn new(data : &'a [T], r : usize, result : Rc<RefCell<&'a mut [&'a T]>>) -> GosperCombinationCellIter<'a, T> { let mut x : u128 = 1; x <<= r; x -= 1; let n = data.len(); GosperCombinationCellIter { data : data, len : divide_factorial(n, multiply_factorial(n - r, r)), r : r, x : x, result : result } } /// Total number of combinations this iterate can return. /// It will equals to n!/((n-r)!*r!) pub fn len(&self) -> usize { self.len } } impl<'a, T> IntoIterator for GosperCombinationCellIter<'a, T> { type Item = (); type IntoIter = CombinationCellIter<'a, T>; fn into_iter(self) -> CombinationCellIter<'a, T> { CombinationCellIter { data : self.data, r : self.r, x : self.x, result : self.result } } } /// # Deprecated /// /// An iterator return from [struct GosperCombination](struct.GosperCombinationIterator.html) /// or from [trait Combination](trait.Combination.html) over slice or vec of data. pub struct CombinationCellIter<'a, T> where T : 'a { data : &'a [T], // original data r : usize, // len of each combination x : u128, // Gosper binary map result : Rc<RefCell<&'a mut[&'a T]>> } impl<'a, T> Iterator for CombinationCellIter<'a, T> { type Item = (); fn next(&mut self) -> Option<()> { if 128 - self.x.leading_zeros() as usize > self.data.len() { return None } // else { // let mut i = 0; // let mut j = 0; // let mut mask = self.x; // while mask > 0 { // if mask & 1 == 1 { // self.result.borrow_mut()[i] = &self.data[j]; // i += 1; // } // mask >>= 1; // j += 1; // } // } // stanford_combination(&mut self.x); let data = self.data; let map = &mut self.x; let mut result = self.result.borrow_mut(); _gosper_next_core(map, #[inline(always)] |i, j| { result[i] = &data[j]; } ); return Some(()) } } impl<'a, T> IteratorReset for CombinationCellIter<'a, T> { fn reset(&mut self) { self.x = 1; self.x <<= self.r; self.x -= 1; } } impl<'a, T> ExactSizeIterator for CombinationCellIter<'a, T> { fn len(&self) -> usize { let n = self.data.len(); divide_factorial(n, multiply_factorial(n - self.r, self.r)) } } /// # Deprecated /// This iterator family is now deprecated. /// Consider using [LargeCombinationCellIter](struct.LargeCombinationCellIter.html) /// instead. This is because current implementation need to copy every ref /// on every iteration which is inefficient. /// On uncontroll test environment, this iterator take 2.29s to iterate over /// 30,045,015 combinations. The [LargeCombinationCellIter](struct.LargeCombinationCellIter.html) /// took only 345.44ms. /// /// Create an unsafe combination iterator that return result to mutable pointer. /// It use Gosper's algorithm to pick a combination out of /// given data. The produced combination provide no lexicographic /// order. /// /// The returned combination will be a reference into given data. /// Each combination return from iterator by storing into given /// *mut [&T] along with empty Option. /// /// # Unsafe /// This object took raw mutable pointer and convert in upon object /// instantiation via [new function](struct.GosperCombinationRefIter.html#method.new) /// thus all unsafe Rust conditions will be applied on all method. /// /// # Rationale /// It uses unsafe to take a mutable pointer to store the result /// to avoid the cost of using Rc<RefCell<>>. /// In uncontroll test environment, this struct perform a complete /// iteration over 657,800 combinations in about 47ms where /// [GosperCombinationCellIter](struct.GosperCombinationCellIter.html) /// took about 52ms. /// This function is very much alike /// [unsafe_combination function](fn.unsafe_combination.html) /// but took `Iterator` approach. /// /// # Examples /// Given slice of [1, 2, 3, 4, 5]. It will produce following /// combinations: /// [1, 2, 3], [1, 2, 4], [1, 3, 4], [2, 3, 4], [1, 2, 5], /// [1, 3, 5], [2, 3, 5], [1, 4, 5], [2, 4, 5], [3, 4, 5] /// Here's an example of code printing above combination. /// ``` /// use permutator::{GosperCombinationRefIter}; /// use std::time::{Instant}; /// let data = &[1, 2, 3, 4, 5]; /// let mut result : &mut[&i32] = &mut [&data[0]; 3]; /// unsafe { /// let mut gosper = GosperCombinationRefIter::new(&[1, 2, 3, 4, 5], 3, result as *mut [&i32]); /// let mut counter = 0; /// let timer = Instant::now(); /// /// for _ in gosper { /// println!("{}:{:?}", counter, result); /// counter += 1; /// } /// /// println!("Total {} combinations in {:?}", counter, timer.elapsed()); /// } /// ``` /// /// # Limitation /// Gosper algorithm need to know the MSB (most significant bit). /// The current largest known MSB data type is u128. /// This make the implementation support up to 128 elements slice. /// /// # See /// - [Gospel's algorithm in Wikipedia page, October 9, 2018](https://en.wikipedia.org/wiki/Combinatorial_number_system#Applications) pub struct GosperCombinationRefIter<'a, T> where T : 'a { data : &'a [T], // data to generate a combination len : usize, // total possible number of combination. r : usize, // a size of combination. x : u128, // A binary map to generate combination result : &'a mut [&'a T] } impl<'a, T> GosperCombinationRefIter<'a, T> { /// Create new combination generator using Gosper's algorithm. /// `r` shall be smaller than data.len(). /// /// Note: It perform no check on given parameter. /// If r is larger than length of data then iterate over it /// will not occur. The iteration will be end upon enter. pub unsafe fn new(data : &'a [T], r : usize, result : *mut [&'a T]) -> GosperCombinationRefIter<'a, T> { let mut x : u128 = 1; x <<= r; x -= 1; let n = data.len(); GosperCombinationRefIter { data : data, len : divide_factorial(n, multiply_factorial(n - r, r)), r : r, x : x, result : &mut *result } } /// Total number of combinations this iterate can return. /// It will equals to n!/((n-r)!*r!) pub fn len(&self) -> usize { self.len } } impl<'a, T> IntoIterator for GosperCombinationRefIter<'a, T> { type Item = (); type IntoIter = CombinationRefIter<'a, T>; fn into_iter(self) -> CombinationRefIter<'a, T> { CombinationRefIter { data : self.data, r : self.r, x : self.x, result : self.result } } } /// # Deprecated /// /// An iterator return from [struct GosperCombination](struct.GosperCombinationIterator.html) /// or from [trait Combination](trait.Combination.html) over slice or vec of data. pub struct CombinationRefIter<'a, T> where T : 'a { data : &'a [T], // original data r : usize, // len of each combination x : u128, // Gosper binary map result : &'a mut[&'a T] } impl<'a, T> Iterator for CombinationRefIter<'a, T> { type Item = (); fn next(&mut self) -> Option<()> { if 128 - self.x.leading_zeros() as usize > self.data.len() { return None } // else { // let mut i = 0; // let mut j = 0; // let mut mask = self.x; // while mask > 0 { // if mask & 1 == 1 { // self.result[i] = &self.data[j]; // i += 1; // } // mask >>= 1; // j += 1; // } // } // stanford_combination(&mut self.x); let data = self.data; let map = &mut self.x; let result = &mut self.result; _gosper_next_core(map, #[inline(always)] |i, j| { result[i] = &data[j]; } ); return Some(()) } } impl<'a, T> IteratorReset for CombinationRefIter<'a, T> { fn reset(&mut self) { self.x = 1; self.x <<= self.r; self.x -= 1; } } impl<'a, T> ExactSizeIterator for CombinationRefIter<'a, T> { fn len(&self) -> usize { let n = self.data.len(); divide_factorial(n, multiply_factorial(n - self.r, self.r)) } } /// A core logic of `next` function of `LargeCombination` iterator family. /// /// # Parameters /// 1. `c` - a ref mut slice to usize. It's current cursor state in iterator /// 2. `data` - a ref slice to data to get a combination from. /// 3. `iterated` - A ref mut to empty Option. If none, it mean this is first call /// to the function. /// 4. `r` - A size of combination /// 5. `result` - A ref mut to result container /// 6. `result_change_fn` - A closure that accept parameter `usize`, `usize`, and `&mut R`. /// It responsible to assign a new value to R. The first usize is a slot of R /// to be updated. The second usize is the index to `data`. /// 7. `result_fn` - A function that make result ready for comsumption. #[inline(always)] fn _large_comb_next_core<'a, T, R, V>( c : &mut [usize], data : & [T], iterated : &mut Option<()>, r : usize, result : &mut R, mut result_change_fn : impl FnMut(usize, usize, &mut R), result_fn : impl Fn(&R) -> V ) -> Option<V> where T : 'a, { /// Move cursor and update result #[inline(always)] fn move_cur_res<'a, T, R>( c : &mut [usize], domain : &'a [T], result : &mut R, mut next_result_fn : impl FnMut(usize, usize, &mut R) ) -> Option<()> { let n = c.len(); let max = domain.len(); let mut i = c.len() - 1; if c[i] < max - n + i { c[i] += 1; next_result_fn(i, c[i], result); Some(()) } else { // find where to start reset cursor while c[i] >= max - n + i && i > 0 { i -= 1; } if c[0] >= max - n { // first slot already on last possible value return None; } c[i] += 1; next_result_fn(i, c[i], result); i += 1; // reset all cursor from `i + 1` (i..c.len()).for_each(|i| { c[i] = c[i - 1] + 1; next_result_fn(i, c[i], result); }); Some(()) } } /// Init first result. /// It'd be call only once to populate the result #[inline(always)] fn init_once<'a, F, R>( c : &mut [usize], r : usize, result : &mut R, result_change_fn : &mut F ) -> Option<()> where for<'r> F : FnMut(usize, usize, &mut R), { (0..r).for_each(|i| { result_change_fn(i, i, result); c[i] = i; }); return Some(()); } if let None = iterated { *iterated = Some(()); init_once(c, r, result, &mut result_change_fn); // handle special case where data.len() == 1 if data.len() == 1 { c[0] = 1; // force cursor to go move or next call will reinit result } return Some(result_fn(&*result)); } match move_cur_res(c, data, result, result_change_fn) { Some(_) => Some(result_fn(&*result)), None => None } } /// Create a combination iterator. /// The result is lexicographic ordered if input is lexicorgraphic ordered. /// The returned combination will be a reference into given data. /// Each combination return from iterator will be a new Vec. /// It's safe to hold onto a combination or `collect` it. /// /// # Examples /// Given slice of [1, 2, 3, 4, 5]. It will produce following /// combinations: /// [1, 2, 3], [1, 2, 4], [1, 3, 4], [2, 3, 4], [1, 2, 5], /// [1, 3, 5], [2, 3, 5], [1, 4, 5], [2, 4, 5], [3, 4, 5] /// Here's an example of code printing above combination. /// ``` /// use permutator::LargeCombinationIterator; /// use std::time::{Instant}; /// let lc = LargeCombinationIterator::new(&[1, 2, 3, 4, 5], 3); /// let mut counter = 0; /// let timer = Instant::now(); /// /// for combination in lc { /// println!("{}:{:?}", counter, combination); /// counter += 1; /// } /// /// println!("Total {} combinations in {:?}", counter, timer.elapsed()); /// ``` /// /// # Panic /// It panic if `r == 0` or `r > data.len()` pub struct LargeCombinationIterator<'a, T> where T : 'a { c : Vec<usize>, // cursor for each combination slot data : &'a [T], // data to generate a combination i : usize, // slot index being mutate. nexted : Option<()>, // If iterated at least once, it'd be Some(()). Otherwise, None. len : usize, // total possible number of combination. r : usize, // a size of combination. result : Vec<&'a T>, // result container } impl<'a, T> LargeCombinationIterator<'a, T> { pub fn new(data : &[T], r : usize) -> LargeCombinationIterator<T> { assert_ne!(r, 0); assert!(r <= data.len()); let c = vec![0; r]; let n = data.len(); let result = vec![&data[0]; r]; LargeCombinationIterator { c, data : data, i : 0, nexted : None, len : divide_factorial(n, multiply_factorial(n - r, r)), r : r, result : result } } pub fn iter(&mut self) -> &mut Self { self } } impl<'a, T> Iterator for LargeCombinationIterator<'a, T> { type Item = Vec<&'a T>; fn next(&mut self) -> Option<Vec<&'a T>> { let data = &self.data; _large_comb_next_core( &mut self.c, data, &mut self.nexted, self.r, &mut self.result, |i, j, r| { r[i] = &data[j]; }, |r| { r.to_owned() } ) } } impl<'a, T> IteratorReset for LargeCombinationIterator<'a, T> { fn reset(&mut self) { self.nexted = None; self.c.iter_mut().for_each(|c| *c = 0); self.i = 0; } } impl<'a, T> ExactSizeIterator for LargeCombinationIterator<'a, T> { fn len(&self) -> usize { self.len } } /// Create a combination iterator. /// The result is lexicographic ordered if input is lexicorgraphic ordered. /// The returned combination will be a reference into given data. /// Each combination return from iterator is stored into given /// Rc<RefCell<&mut [&T]>>. /// /// The result will be overwritten on every iteration. /// To reuse a result, convert a result to owned value. /// If most result need to be reused, consider using /// [LargeCombinationIterator](struct.LargeCombinationIterator.html) /// /// # Examples /// Given slice of [1, 2, 3, 4, 5]. It will produce following /// combinations: /// [1, 2, 3], [1, 2, 4], [1, 3, 4], [2, 3, 4], [1, 2, 5], /// [1, 3, 5], [2, 3, 5], [1, 4, 5], [2, 4, 5], [3, 4, 5] /// Here's an example of code printing above combination. /// ``` /// use permutator::{LargeCombinationCellIter}; /// use std::cell::RefCell; /// use std::rc::Rc; /// use std::time::{Instant}; /// let data = &[1, 2, 3, 4, 5]; /// let mut result : &mut[&i32] = &mut [&data[0]; 3]; /// let shared = Rc::new(RefCell::new(result)); /// let mut lc = LargeCombinationCellIter::new(&[1, 2, 3, 4, 5], 3, Rc::clone(&shared)); /// let mut counter = 0; /// let timer = Instant::now(); /// /// for _ in lc { /// println!("{}:{:?}", counter, shared); /// counter += 1; /// } /// /// println!("Total {} combinations in {:?}", counter, timer.elapsed()); /// ``` /// /// # Panic /// It panic if `r > data.len()` or `r == 0` pub struct LargeCombinationCellIter<'a, T> where T : 'a { c : Vec<usize>, // cursor for each combination slot data : &'a [T], // data to generate a combination i : usize, // slot index being mutate. nexted : Option<()>, // If iterated at least once, it'd be Some(()). Otherwise, None. len : usize, // total possible number of combination. r : usize, // a size of combination. result : Rc<RefCell<&'a mut [&'a T]>> } impl<'a, T> LargeCombinationCellIter<'a, T> { pub fn new(data : &'a [T], r : usize, result : Rc<RefCell<&'a mut [&'a T]>>) -> LargeCombinationCellIter<'a, T> { assert_ne!(r, 0); assert!(r <= data.len()); let c = vec![0; r]; let n = data.len(); LargeCombinationCellIter { c, data : data, i : 0, nexted : None, len : divide_factorial(n, multiply_factorial(n - r, r)), r : r, result : result } } pub fn iter(&mut self) -> &mut Self { self } } impl<'a, T> Iterator for LargeCombinationCellIter<'a, T> { type Item = (); fn next(&mut self) -> Option<()> { let data = &self.data; _large_comb_next_core( &mut self.c, data, &mut self.nexted, self.r, &mut self.result, |i, j, r| { r.borrow_mut()[i] = &data[j]; }, |_| { () } ) } } impl<'a, T> IteratorReset for LargeCombinationCellIter<'a, T> { fn reset(&mut self) { self.nexted = None; self.c.iter_mut().for_each(|c| *c = 0); self.i = 0; } } impl<'a, T> ExactSizeIterator for LargeCombinationCellIter<'a, T> { fn len(&self) -> usize { self.len } } /// Create an unsafe combination iterator that return result to mutable pointer. /// The result is lexicographic ordered if input is lexicorgraphic ordered. /// The returned combination will be a reference into given data. /// Each combination return from iterator is stored into given /// *mut [&T]. /// /// The result will be overwritten on every iteration. /// To reuse a result, convert a result to owned value. /// If most result need to be reused, consider using /// [LargeCombinationIterator](struct.LargeCombinationIterator.html) /// /// # Safety /// This object took raw mutable pointer and convert in upon object /// instantiation via [new function](struct.LargeCombinationRefIter.html#method.new) /// thus all unsafe Rust conditions will be applied on all method. /// /// # Rationale /// It uses unsafe to take a mutable pointer to store the result /// to avoid the cost of using Rc<RefCell<>>. /// In uncontroll test environment, this struct perform a complete /// iteration over 30,045,015 combinations in about 337ms where /// [LargeCombinationCellIter](struct.LargeCombinationCellIter.html) /// took about 460ms. /// This function is very much alike /// [unsafe_combination function](fn.unsafe_combination.html) /// but took `Iterator` approach. /// /// # Examples /// Given slice of [1, 2, 3, 4, 5]. It will produce following /// combinations: /// [1, 2, 3], [1, 2, 4], [1, 3, 4], [2, 3, 4], [1, 2, 5], /// [1, 3, 5], [2, 3, 5], [1, 4, 5], [2, 4, 5], [3, 4, 5] /// Here's an example of code printing above combination. /// ``` /// use permutator::{LargeCombinationRefIter}; /// use std::time::{Instant}; /// let data = &[1, 2, 3, 4, 5]; /// let mut result : &mut[&i32] = &mut [&data[0]; 3]; /// unsafe { /// let mut comb = LargeCombinationRefIter::new(&[1, 2, 3, 4, 5], 3, result as *mut [&i32]); /// let mut counter = 0; /// let timer = Instant::now(); /// /// for _ in comb { /// println!("{}:{:?}", counter, result); /// counter += 1; /// } /// /// println!("Total {} combinations in {:?}", counter, timer.elapsed()); /// } /// ``` pub struct LargeCombinationRefIter<'a, T> where T : 'a { c : Vec<usize>, // cursor for each combination slot data : &'a [T], // data to generate a combination i : usize, // slot index being mutate. nexted : Option<()>, // If iterated at least once, it'd be Some(()). Otherwise, None. len : usize, // total possible number of combination. r : usize, // a size of combination. result : &'a mut [&'a T] } impl<'a, T> LargeCombinationRefIter<'a, T> { pub unsafe fn new(data : &'a [T], r : usize, result : *mut [&'a T]) -> LargeCombinationRefIter<'a, T> { assert_ne!(r, 0); assert!(r <= (*data).len()); let c = vec![0; r]; let n = data.len(); LargeCombinationRefIter { c, data : data, i : 0, nexted : None, len : divide_factorial(n, multiply_factorial(n - r, r)), r : r, result : &mut *result } } /// Total number of combinations this iterate can return. /// It will equals to n!/((n-r)!*r!) pub fn len(&self) -> usize { self.len } pub fn iter(&mut self) -> &mut Self { self } } impl<'a, T> Iterator for LargeCombinationRefIter<'a, T> { type Item = (); fn next(&mut self) -> Option<()> { let data = &self.data; _large_comb_next_core( &mut self.c, data, &mut self.nexted, self.r, &mut self.result, |i, j, r| { r[i] = &data[j]; }, |_| { () } ) } } impl<'a, T> IteratorReset for LargeCombinationRefIter<'a, T> { fn reset(&mut self) { self.nexted = None; self.c.iter_mut().for_each(|c| *c = 0); self.i = 0; } } impl<'a, T> ExactSizeIterator for LargeCombinationRefIter<'a, T> { fn len(&self) -> usize { self.len } } /// Core logic of `next` function of `HeapPermutation` iterator family. /// /// # Parameters /// 1. `c` - mutable slice of usize. A cursor that pointed to data for /// each permutation slot. /// 2. `i` - the current index pointed to which slot to be permuted. /// 3. `n` - the number of data/slots to be permuted. #[inline(always)] fn _heap_next_core( c : &mut[usize], i : &mut usize, n : usize, mut swap_fn : impl FnMut(usize, usize)) { while *i < n { if c[*i] < *i { if *i % 2 == 0 { // self.data.swap(0, *i); swap_fn(0, *i); } else { swap_fn(c[*i], *i); } c[*i] += 1; *i = 0; return } else { c[*i] = 0; *i += 1; } } } /// Heap's permutation in iterator style implementation. /// /// # Examples /// Iterator style usage example: /// ``` /// use permutator::HeapPermutationIterator; /// use std::time::{Instant}; /// let data = &mut [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; /// println!("0:{:?}", data); /// let mut permutator = HeapPermutationIterator::new(data); /// let timer = Instant::now(); /// let mut counter = 1; /// /// for permutated in permutator { /// // println!("{}:{:?}", counter, permutated); /// counter += 1; /// } /// /// // or use iterator related functional approach like line below. /// // permutator.into_iter().for_each(|permutated| {counter += 1;}); /// /// println!("Done {} permutations in {:?}", counter, timer.elapsed()); /// ``` /// # See /// - [Heap's algorithm in Wikipedia page, October 9, 2018](https://en.wikipedia.org/wiki/Heap%27s_algorithm) pub struct HeapPermutationIterator<'a, T> where T : 'a { c : Box<[usize]>, data : &'a mut [T], i : usize } impl<'a, T> HeapPermutationIterator<'a, T> { /// Construct a new permutation iterator. /// Note: the provided parameter will get mutated /// in placed at first call to next. pub fn new(data : &mut [T]) -> HeapPermutationIterator<T> { HeapPermutationIterator { c : vec![0; data.len()].into_boxed_slice(), data : data, i : 0 } } /// Consume itself immediately return it. /// It mimic how `IntoIterator` trait perform except /// that this struct itself implement `Iterator` trait. pub fn into_iter(self) -> Self { self } } impl<'a, T> Iterator for HeapPermutationIterator<'a, T> where T : Clone { type Item = Vec<T>; fn next(&mut self) -> Option<Self::Item> { let HeapPermutationIterator {ref mut c, ref mut data, ref mut i } = self; let n = data.len(); let mut result : Option<Vec<T>> = None; _heap_next_core(c, i, n, #[inline(always)] |from, to| { data.swap(from, to); result = Some(data.to_owned()); } ); result } } impl<'a, T> IteratorReset for HeapPermutationIterator<'a, T> { /// Reset this permutator so calling next will continue /// permutation on current permuted data. /// It will not reset permuted data. fn reset(&mut self) { self.i = 0; self.c.iter_mut().for_each(|c| {*c = 0;}); } } impl<'a, T> ExactSizeIterator for HeapPermutationIterator<'a, T> where T : Clone { fn len(&self) -> usize { factorial(self.data.len()) } } /// Heap's permutation in Rc<RefCell<>> mimic Iterator style. /// It provides another choice for user that want to share /// permutation result but doesn't want to clone it for /// each share. It also doesn't create new result on each /// iteration unlike other object that implement `Iterator` trait. /// # Rationale /// Unlike all other struct, HeapPermutationIterator permute value in place. /// If HeapPermutationIterator struct implement IteratorCell itself will /// result in the `data` inside struct left unused. /// This struct introduce the same concept to other struct that /// implement `IteratorCell`, to be able to easily share /// result with as less performance overhead as possible. /// /// The implementation take Rc<RefCell<&mut [T]>> instead of regular /// slice like other permutation struct. /// It implements `Iterator` trait with empty associated type because /// it doesn't return value. It permutes the data in place thus /// every owner of Rc<RefCell<&mut [T]>> will always has an up-to-date /// slice. /// # Examples /// Iterator style usage example: /// ``` /// use permutator::HeapPermutationCellIter; /// use std::cell::RefCell; /// use std::rc::Rc; /// use std::time::{Instant}; /// let data : &mut [i32] = &mut [1, 2, 3, 4, 5]; /// let shared = Rc::new(RefCell::new(data)); /// let mut permutator = HeapPermutationCellIter::new(Rc::clone(&shared)); /// println!("0:{:?}", &*shared.borrow()); /// let timer = Instant::now(); /// let mut counter = 1; /// /// for _ in permutator { // it return empty /// println!("{}:{:?}", counter, &*shared.borrow()); /// counter += 1; /// } /// /// // or use iterator related functional approach like line below. /// // permutator.into_iter().for_each(|_| { /// // println!("{}:{:?}", counter, &*data.borrow()); /// // counter += 1; /// // }); /// /// println!("Done {} permutations in {:?}", counter, timer.elapsed()); /// ``` /// # See /// - [HeapPermutationIterator struct](struct.HeapPermutationIterator.html) pub struct HeapPermutationCellIter<'a, T> where T : 'a { c : Vec<usize>, data : Rc<RefCell<&'a mut[T]>>, i : usize } impl<'a, T> HeapPermutationCellIter<'a, T> { /// Construct a new permutation iterator. /// Note: the provided parameter will get mutated /// in placed at first call to next. pub fn new(data : Rc<RefCell<&'a mut[T]>>) -> HeapPermutationCellIter<'a, T> { HeapPermutationCellIter { c : vec![0; data.borrow().len()], data : Rc::clone(&data), i : 0 } } } impl<'a, T> Iterator for HeapPermutationCellIter<'a, T> where T : 'a { type Item= (); fn next(&mut self) -> Option<()> { let HeapPermutationCellIter {ref mut c, ref mut data, ref mut i } = self; let n = data.borrow().len(); let mut result : Option<()> = None; _heap_next_core(c, i, n, #[inline(always)] |from, to| { data.borrow_mut().swap(from, to); result = Some(()); } ); result } } impl<'a, T> IteratorReset for HeapPermutationCellIter<'a, T> { /// Reset this permutator so calling next will continue /// permutation on current permuted data. /// It will not reset permuted data. fn reset(&mut self) { self.i = 0; self.c.iter_mut().for_each(|c| {*c = 0;}); } } impl<'a, T> ExactSizeIterator for HeapPermutationCellIter<'a, T> { fn len(&self) -> usize { factorial(self.data.borrow().len()) } } /// An unsafe Heap's permutation in iterator style implementation. /// /// # Examples /// - Iterator style usage example: /// ``` /// use permutator::HeapPermutationRefIter; /// use std::time::{Instant}; /// let data : &mut[i32] = &mut [1, 2, 3, 4, 5]; /// println!("0:{:?}", data); /// unsafe { /// let mut permutator = HeapPermutationRefIter::new(data as *mut[i32]); /// let timer = Instant::now(); /// let mut counter = 1; /// /// for permutated in permutator { /// println!("{}:{:?}", counter, permutated); /// counter += 1; /// } /// /// // or use iterator related functional approach like line below. /// // permutator.into_iter().for_each(|permutated| {counter += 1;}); /// /// println!("Done {} permutations in {:?}", counter, timer.elapsed()); /// } /// ``` /// In test environment, given a slice of 8 strings. It has about 40 characters each. /// This implementation is about 70 times (33ms vs 0.47ms) faster than a [HeapPermutation](struct.HeapPermutation.html) /// iteration. This is because each `next` function doesn't clone/copy the value. /// However, this implementation limited the way to use data because each iteration /// permute the result in place. It require user to manually sync the share operation. /// # See /// - [Heap's algorithm in Wikipedia page, October 9, 2018](https://en.wikipedia.org/wiki/Heap%27s_algorithm) pub struct HeapPermutationRefIter<'a, T> where T : 'a { c : Vec<usize>, data : &'a mut [T], i : usize } impl<'a, T> HeapPermutationRefIter<'a, T> { /// Construct a new permutation iterator. /// Note: the provided parameter will get mutated /// in placed at first call to next. pub unsafe fn new(data : *mut [T]) -> HeapPermutationRefIter<'a, T> { HeapPermutationRefIter { c : vec![0; (*data).len()], data : &mut *data, i : 0 } } /// Consume itself immediately return it. /// It mimic how `IntoIterator` trait perform except /// that this struct itself implement `Iterator` trait. pub fn into_iter(self) -> Self { self } } impl<'a, T> Iterator for HeapPermutationRefIter<'a, T> { type Item = (); fn next(&mut self) -> Option<Self::Item> { let HeapPermutationRefIter {ref mut c, ref mut data, ref mut i } = self; let n = data.len(); let mut result : Option<()> = None; _heap_next_core(c, i, n, #[inline(always)] |from, to| { data.swap(from, to); result = Some(()); } ); result } } impl<'a, T> IteratorReset for HeapPermutationRefIter<'a, T> { /// Reset this permutator so calling next will continue /// permutation on current permuted data. /// It will not reset permuted data. fn reset(&mut self) { self.i = 0; self.c.iter_mut().for_each(|c| {*c = 0;}); } } impl<'a, T> ExactSizeIterator for HeapPermutationRefIter<'a, T> { fn len(&self) -> usize { factorial(self.data.len()) } } /// k-permutation iterator common code to perform /// `next` element operation. /// /// # Parameters /// 1. `combinator` - A combination iterator object /// 2. `permutator` - An Option holding permutation iterator object /// 4. `new_permutator_fn` - A closure that create new permutation iterator #[inline(always)] fn _k_permutation_next_core<'a, T, U, V, W, X>( combinator : T, permutator : &'a mut Option<U>, permuted : X, new_permutator_fn : impl FnOnce(&'a mut Option<U>, X, V) + 'a ) -> Option<()> where T : Iterator<Item=V> + 'a, U : Iterator<Item=W> + IteratorReset + 'a, V : 'a, X : 'a { #[inline(always)] fn get_next<'a, T, U, V, W, X>( combinator : T, permutator : &'a mut Option<U>, permuted : X, new_permutator_fn : impl FnOnce(&'a mut Option<U>, X, V) ) -> Option<()> where T : Iterator<Item=V> + 'a, U : Iterator<Item=W> + IteratorReset + 'a, V : 'a, X : 'a { if let Some(ref mut perm) = *permutator { // permutator already exist if let Some(_) = perm.next() { // get next permutation of current permutator return Some(()); } } // permutator is not exist yet. if let Ok(_) = next_permutator(combinator, permutator, permuted, new_permutator_fn) { // success create new permutator Some(()) } else { // no more combination to permute return None; } } #[inline(always)] fn next_permutator<'a, T, U, V, W, X>( mut combinator : T, permutator : &'a mut Option<U>, permuted : X, new_permutator_fn : impl FnOnce(&'a mut Option<U>, X, V) ) -> Result<(), ()> where T : Iterator<Item = V> + 'a, U : Iterator<Item=W> + IteratorReset + 'a, V : 'a, X : 'a { if let Some(v) = combinator.next() { new_permutator_fn(&mut *permutator, permuted, v); Ok(()) } else { Err(()) } } get_next(combinator, permutator, permuted, new_permutator_fn) } /// k-Permutation over data of length n where k must be /// less than n. /// It'll attempt to permute given data by pick `k` elements /// out of data. It use Gosper algorithm to pick the elements. /// It then use Heap's algorithm to permute those `k` elements /// and return each permutation back to caller. /// /// # Examples /// - Iterator style permit using 'for-in' style loop along with /// enable usage of functional paradigm over iterator object. /// ``` /// use permutator::KPermutationIterator; /// use std::time::Instant; /// let data = [1, 2, 3, 4, 5]; /// let permutator = KPermutationIterator::new(&data, 3); /// let mut counter = 0; /// // println!("Begin testing KPermutation"); /// let timer = Instant::now(); /// /// for permuted in permutator { /// // uncomment a line below to print all permutation. /// // println!("{}:{:?}", counter, permuted); /// counter += 1; /// } /// /// // Or simply use functional paradigm of iterator like below /// // permutator.into_iter().any(|item| {item == [7, 8, 9]}); /// /// println!("Total {} permutations done in {:?}", counter, timer.elapsed()); /// assert_eq!(60, counter); /// ``` /// /// # Notes /// The additional functionality provided by this struct is that it can be /// pause or completely stop midway while the [k-permutation](fn.k_permutation.html) /// need to be run from start to finish only. /// /// # Safety /// This struct implementation use unsafe code internally. /// It use unsafe because it uses `Vec<T>` to own a combination /// for each permutation. Rust cannot derive lifetime of mutable /// slice created inside next and store it into struct object itself. /// This is because `next` signature have no lifetime associated /// with `self`. To get around this, the implementation convert /// Vec<T> to `*mut [T]` then perform `&mut *` on it. /// /// # See /// - [GosperCombination](struct.GoserPermutation.html) /// - [HeapPermutation](struct.HeapPermutationIterator.html) pub struct KPermutationIterator<'a, T> where T : 'a { permuted : Vec<&'a T>, len : usize, combinator : LargeCombinationIterator<'a, T>, permutator : Option<HeapPermutationIterator<'a, &'a T>> } impl<'a, T> KPermutationIterator<'a, T> { pub fn new(data : &[T], k : usize) -> KPermutationIterator<T> { assert_ne!(k, 0); assert!(k <= data.len()); let combinator = LargeCombinationIterator::new(data, k); let n = data.len(); let permuted = vec![&data[0]; k]; KPermutationIterator { permuted : permuted, len : divide_factorial(n, n - k), combinator : combinator, permutator : None } } /// Consume then return self immediately. /// It permit functional style operation over iterator /// from borrow object as Rust isn't yet support /// `for _ in borrowed_object` directly. /// It need to be `for _ in borrowed_object.into_iter()`. pub fn into_iter(self) -> Self { self } } impl<'a, T> Iterator for KPermutationIterator<'a, T> { type Item = Vec<&'a T>; fn next(&mut self) -> Option<Vec<&'a T>> { let combinator = &mut self.combinator; let permutator = &mut self.permutator; let permuted = self.permuted.as_mut_slice() as *mut [&T]; unsafe { if let Some(_) = _k_permutation_next_core( combinator, permutator, &mut *permuted, #[inline(always)] |permutator, permuted, comb| { permuted.copy_from_slice(comb.as_slice()); *permutator = Some(HeapPermutationIterator::new(permuted)); } ) { Some(self.permuted.to_owned()) } else { None } } } } impl<'a, T> IteratorReset for KPermutationIterator<'a, T> { fn reset(&mut self) { self.combinator.reset(); self.permutator = None; } } impl<'a, T> ExactSizeIterator for KPermutationIterator<'a, T> { fn len(&self) -> usize { self.len } } /// k-Permutation over data of length "n" where `k` must be /// less than `n`. /// It'll attempt to permute given data by pick `k` elements /// out of `n` data. It use Gosper algorithm to pick the elements. /// It then use Heap's algorithm to permute those `k` elements /// and return each permutation back to caller by given /// Rc<RefCell<&mut [&T]>> parameter to /// [new method of KPermutationCellIter](struct.KPermutationCellIter.html#method.new). /// /// # Examples /// - Iterator style permit using 'for-in' style loop along with /// enable usage of functional paradigm over iterator object. /// ``` /// use permutator::{KPermutationCellIter, IteratorReset}; /// use std::cell::RefCell; /// use std::rc::Rc; /// use std::time::Instant; /// let data = [1, 2, 3, 4, 5]; /// let mut result : Vec<&i32> = vec![&data[0]; 3]; /// let shared = Rc::new(RefCell::new(result.as_mut_slice())); /// let mut permutator = KPermutationCellIter::new(&data, 3, Rc::clone(&shared)); /// let mut counter = 0; /// let timer = Instant::now(); /// /// permutator.for_each(|_| { /// println!("{}:{:?}", counter, &*shared.borrow()); /// counter += 1; /// }); /// /// println!("Total {} permutations done in {:?}", counter, timer.elapsed()); /// assert_eq!(60, counter); /// ``` /// /// # Notes /// This struct manual iteration performance is about 110% slower than using /// [k-permutation](fn.k_permutation.html) function /// while the slowest using Iterator style is about 2300% slower. /// The additional functionality provided by this struct is that it can be /// pause or completely stop midway while the [k-permutation](fn.k_permutation.html) /// need to be run from start to finish only. /// /// # Warning /// This struct implementation use unsafe code. /// This is because inside the `next` function, it require /// a share mutable variable on both the Gosper iterator and /// Heap permutator. It also require to re-assign the /// permutator on first call to `next` which is impossible in current safe Rust. /// To do it in safe Rust way, it need to copy the data /// which will hurt performance. /// /// # See /// - [HeapPermutation](struct.HeapPermutationIterator.html) pub struct KPermutationCellIter<'a, T> where T : 'a { permuted : Rc<RefCell<&'a mut [&'a T]>>, len : usize, combinator : LargeCombinationIterator<'a, T>, permutator : Option<HeapPermutationCellIter<'a, &'a T>> } impl<'a, T> KPermutationCellIter<'a, T> { pub fn new(data : &'a [T], k : usize, result : Rc<RefCell<&'a mut [&'a T]>>) -> KPermutationCellIter<'a, T> { let combinator = LargeCombinationIterator::new(data, k); let n = data.len(); KPermutationCellIter { permuted : result, len : divide_factorial(n, n - k), combinator : combinator, permutator : None } } /// Consume then return self immediately. /// It permit functional style operation over iterator /// from borrow object as Rust isn't yet support /// `for _ in borrowed_object` directly. /// It need to be `for _ in borrowed_object.into_iter()`. pub fn into_iter(self) -> Self { self } /// Get total number of permutation this KPermutationIterator object /// can permute. It'll be equals to number of possible `next` /// call. pub fn len(&self) -> usize { self.len } } impl<'a, T> Iterator for KPermutationCellIter<'a, T> { type Item = (); fn next(&mut self) -> Option<()> { let permutator = &mut self.permutator; let permuted = Rc::clone(&self.permuted); if let Some(_) = _k_permutation_next_core( &mut self.combinator, permutator, permuted, #[inline(always)] |permutator, permuted, comb| { permuted.borrow_mut().iter_mut().enumerate().for_each(|(i, p)| *p = comb[i]); if let Some(p) = permutator { p.reset(); } else { *permutator = Some(HeapPermutationCellIter::new(permuted)); } }) { return Some(()); } else { return None; } } } impl<'a, T> IteratorReset for KPermutationCellIter<'a, T> { fn reset(&mut self) { self.combinator.reset(); self.permutator = None; } } impl<'a, T> ExactSizeIterator for KPermutationCellIter<'a, T> { fn len(&self) -> usize { self.len } } /// k-Permutation over data of length "n" where `k` must be /// less than `n` and store result into mutable pointer. /// It'll attempt to permute given data by pick `k` elements /// out of `n` data. It use Gosper algorithm to pick the elements. /// It then use Heap's algorithm to permute those `k` elements /// and return each permutation back to caller by given /// *mut [&T]>> parameter to /// [new method of KPermutationRefIter](struct.KPermutationRefIter.html#method.new). /// /// # Safety /// This object use raw mutable pointer provided from user and keep using it /// in each `next` iteration. Therefore, all raw pointer conditions are applied /// up until this object is dropped. /// /// # Rationale /// It uses unsafe to take a mutable pointer to store the result /// to avoid the cost of using Rc<RefCell<>>. /// In uncontroll test environment, this struct perform a complete /// iteration over 8,648,640 permutations in about 66ms where /// [KPermutationCellIter](struct.KPermutationCellIter.html) /// took about 125 ms. /// This function is very much alike /// [unsafe_k_permutation function](fn.unsafe_k_permutation.html) /// but took `Iterator` approach. /// /// # Examples /// - Iterator style permit using 'for-in' style loop along with /// enable usage of functional paradigm over iterator object. /// ``` /// use permutator::{KPermutationCellIter, IteratorReset}; /// use std::cell::RefCell; /// use std::rc::Rc; /// use std::time::Instant; /// let data = [1, 2, 3, 4, 5]; /// let mut result : Vec<&i32> = vec![&data[0]; 3]; /// let shared = Rc::new(RefCell::new(result.as_mut_slice())); /// let mut permutator = KPermutationCellIter::new(&data, 3, Rc::clone(&shared)); /// let mut counter = 0; /// let timer = Instant::now(); /// /// permutator.for_each(|_| { /// println!("{}:{:?}", counter, &*shared.borrow()); /// counter += 1; /// }); /// /// println!("Total {} permutations done in {:?}", counter, timer.elapsed()); /// assert_eq!(60, counter); /// ``` /// /// # Notes /// This struct manual iteration performance is about 110% slower than using /// [k-permutation](fn.k_permutation.html) function /// while the slowest using Iterator style is about 2300% slower. /// The additional functionality provided by this struct is that it can be /// pause or completely stop midway while the [k-permutation](fn.k_permutation.html) /// need to be run from start to finish only. /// /// # See /// - [HeapPermutation](struct.HeapPermutationIterator.html) pub struct KPermutationRefIter<'a, T> where T : 'a { permuted : *mut [&'a T], len : usize, combinator : LargeCombinationIterator<'a, T>, permutator : Option<HeapPermutationIterator<'a, &'a T>> } impl<'a, T> KPermutationRefIter<'a, T> { pub unsafe fn new(data : &'a [T], k : usize, result : *mut [&'a T]) -> KPermutationRefIter<'a, T> { let combinator = LargeCombinationIterator::new(data, k); let n = data.len(); KPermutationRefIter { permuted : result, len : divide_factorial(n, n - k), combinator : combinator, permutator : None } } /// Consume then return self immediately. /// It permit functional style operation over iterator /// from borrow object as Rust isn't yet support /// `for _ in borrowed_object` directly. /// It need to be `for _ in borrowed_object.into_iter()`. pub fn into_iter(self) -> Self { self } /// Get total number of permutation this KPermutationIterator object /// can permute. It'll be equals to number of possible `next` /// call. pub fn len(&self) -> usize { self.len } } impl<'a, T> Iterator for KPermutationRefIter<'a, T> { type Item = (); fn next(&mut self) -> Option<()> { let permutator = &mut self.permutator; let permuted = self.permuted as *mut [&T]; unsafe { if let Some(_) = _k_permutation_next_core( &mut self.combinator, permutator, &mut *permuted, #[inline(always)] |permutator, permuted, comb| { permuted.iter_mut().enumerate().for_each(|(i, p)| *p = comb[i]); if let Some(p) = permutator { p.reset(); } else { *permutator = Some(HeapPermutationIterator::new(&mut *permuted)); } }) { return Some(()); } else { return None; } } } } impl<'a, T> IteratorReset for KPermutationRefIter<'a, T> { fn reset(&mut self) { self.combinator.reset(); self.permutator = None; } } impl<'a, T> ExactSizeIterator for KPermutationRefIter<'a, T> { fn len(&self) -> usize { self.len } } /// Core logic for XPermutation /// /// # Parameters /// - `a : Vec<usize>` - A vec that contains an index of data currently put into result. /// - `k : usize` - An index of result to be mutated. /// - `l : Vec<usize>` - A vec that contains an index of next data to be put into data. /// - `n : usize` - Total number of data. /// - `p : usize` - An index used for queueing next index or backtrack the traversal. /// - `q : usize` - An index of data to be put into result. /// - `u : Vec<usize>` - A vec cantains an index of data to be put into result when /// algorithm need to be backtracked. /// - `result_fn : FnMut(usize, usize)` - Function that mutate result. /// - `t : FnMut(usize) -> bool` - Function that will be called to check if the branch /// need to be traversed. If it return true, the branch will be traversed. If it return /// false, the current branch will be skip and it'll be backtrack one level. /// The first usize is an index of result to be mutated. /// The second usize is an index of data to be put into result. /// /// # Return /// An empty `Option`. When it's `Some`, it means the new result is updated. When it's /// `None`, it means there's no next permutation. fn _x_permutation_next_core( a : &mut [usize], k : &mut usize, l : &mut [usize], n : usize, p : &mut usize, q : &mut usize, u : &mut [usize], mut result_fn : impl FnMut(usize, usize), mut t : impl FnMut(usize) -> bool ) -> Option<()> { /// Return tuple of (p, q) where /// p = 0 and q = l[0] #[inline(always)] fn enter(l : &[usize]) -> (usize, usize) { return (0, l[0]) } while *k != 0 { // "Algo X" X3 // perm[k - 1] = &d[q - 1]; result_fn(*k - 1, *q - 1); a[*k] = *q; if t(*k) { // part of "Algo X" X3 if *k == n { // part of "Algo X" X3 loop { // condition of "Algo X" X5 // "Algo X" X6 *k -= 1; if *k == 0 { break; } else { *p = u[*k]; *q = a[*k]; l[*p] = *q; // "Algo X" X5 *p = *q; *q = l[*p]; if *q != 0 { break; } } } // visit part of "Algo X" X3 return Some(()); } else { // "Algo X" X4 u[*k] = *p; l[*p] = l[*q]; *k += 1; // "Algo X" X2 let (new_p, new_q) = enter(l); *p = new_p; *q = new_q; } } else { // "Algo X" X5 loop { *p = *q; *q = l[*p]; if *q != 0 { break; } // "Algo X" X6 *k -= 1; if *k == 0 { return None; } else { *p = u[*k]; *q = a[*k]; l[*p] = *q; } } } } None } /// A lexicographic ordered permutation based on ["Algoritm X" published by /// Donald E. Knuth.](http://www.cs.utsa.edu/~wagner/knuth/fasc2b.pdf) page 20. /// /// If order is not important, consider using [heap permutation](struct.HeapPermutationIterator.html) /// struct instead. This struct is a bit slower (about 10%) than [heap /// permutation](struct.HeapPermutationIterator.html) in uncontroll test environment. /// /// The algorithm work by simulate tree traversal where some branch can be /// skip altogether. This is archive by provided `t` function that take /// slice of partial result as parameter. If the partial result needed to be skip, /// return false. Otherwise, return true and the algorithm will call this function /// again when the branch is descended deeper. For example: First call to `t` may /// contain [1]. If `t` return true, it will be called again with [1, 2]. If it /// return true, and there's leaf node, cb will be called with [1, 2]. On the other hand, /// if `t` is called with [1, 3] and it return false, it won't call the callback. /// If `t` is called with [4] and it return false, it won't try to traverse deeper even /// if there're [4, 5], or [4, 6]. It will skip altogether and call `t` with [7]. /// The process goes on until every branch is traversed. /// /// # Example /// Get all lexicalgraphic ordered permutation /// ```Rust /// use permutator::XPermutationIterator; /// /// let data = vec![1, 2, 3, 4]; /// let mut counter = 0; /// /// XPermutationIterator::new(&data, |_| true).for_each(|p| { /// println!("{:?}", p); /// counter += 1; /// }); /// /// assert_eq!(factorial(data.len()), counter); /// ``` /// Skip all permutation that has `1` in first element. /// ```Rust /// use permutator::XPermutationIterator; /// /// let data : Vec<u8> = vec![1, 2, 3, 4]; /// let mut counter = 0; /// /// XPermutationIterator::new(&data, |f| { /// *f[0] != 1u8 // filter all permutation that start with 1 /// }).for_each(|p| { /// println!("{:?}", p); /// counter += 1; /// }); /// /// assert_eq!(factorial(data.len()) - factorial(data.len() - 1), counter); /// ``` /// Multi-threads permutation example /// ```Rust /// use permutator::XpermutationIterator; /// use std::time::{Instant}; /// let data : Vec<usize> = (0..4).map(|num| num).collect(); /// let threads = 2; /// let chunk = data.len() / threads; /// let (tx, rx) = mpsc::channel(); /// /// for i in 0..threads { /// let start = chunk * i; /// let end = match i { /// j if j == threads - 1 => data.len(), // last thread handle remaining work /// _ => chunk * (i + 1) /// }; /// /// let l_dat = data.to_owned(); // copy data for each thread /// let end_sig = tx.clone(); /// /// thread::spawn(move || { /// let timer = Instant::now(); /// /// let perm = XPermutationIterator::new( /// &l_dat, /// |v| *v[0] >= start && *v[0] < end // skip branch that is outside the start/end /// ); /// /// let mut counter = 0u64; /// /// for p in perm { /// // each permutation is stored in p /// counter += 1; /// } /// /// end_sig.send(i).unwrap(); /// }); /// } /// /// let main = thread::spawn(move || { // main thread /// let mut counter = 0; /// /// while counter < threads { /// let i = rx.recv().unwrap(); /// // do something /// counter += 1; /// } /// }); /// /// main.join().unwrap(); /// ``` pub struct XPermutationIterator<'a, F, T> where F : FnMut(&[&T]) -> bool, T : 'a { a : Vec<usize>, data : &'a [T], k : usize, l : Vec<usize>, len : usize, n : usize, p : usize, q : usize, result : Vec<&'a T>, t: F, u : Vec<usize>, } impl<'a, F, T> XPermutationIterator<'a, F, T> where F : FnMut(&[&T]) -> bool, T : 'a { /// Construct new XPermutationIterator object. /// /// # Parameters /// - `data : &[T]` - A data used for generate permutation. /// - `t : FnMut(&[&T])` - A function that if return true, will /// make algorithm continue traversing the tree. Otherwise, /// the entire branch will be skip. pub fn new(data : &'a [T], t : F) -> XPermutationIterator<F, T> { let n = data.len(); let mut l : Vec<usize> = (0..n).map(|k| k + 1).collect(); // l[n] = 0 l.push(0); // "Algo X" X1 and X2 XPermutationIterator { a : (0..=n).map(|v| v).collect(), data : data, k : 1, l : l, len : factorial(n), n : n, p : 0, q : 1, result : vec![&data[0]; n], t : t, u : vec![0; n + 1] } } } impl<'a, F, T> Iterator for XPermutationIterator<'a, F, T> where F : FnMut(&[&T]) -> bool, T : 'a { type Item = Vec<&'a T>; fn next(&mut self) -> Option<Self::Item> { let data = self.data; let result = self.result.as_mut_slice(); let result_ptr = &*result as *const [&T]; let t = &mut self.t; if let Some(_) = _x_permutation_next_core( &mut self.a, &mut self.k, &mut self.l, self.n, &mut self.p, &mut self.q, &mut self.u, |k, q| {result[k] = &data[q]}, |k| { unsafe { t(&(*result_ptr)[0..k]) } }) { Some(result.to_owned()) } else { None } } } impl<'a, F, T> IteratorReset for XPermutationIterator<'a, F, T> where F : FnMut(&[&T]) -> bool, T : 'a { fn reset(&mut self) { let n = self.data.len(); let mut l : Vec<usize> = (0..n).map(|k| k + 1).collect(); // l[n] = 0 l.push(0); self.a = (0..=n).map(|v| v).collect(); self.k = 1; self.l = l; self.p = 0; self.q = 1; self.u = vec![0; n + 1]; } } impl<'a, F, T> ExactSizeIterator for XPermutationIterator<'a, F, T> where F : FnMut(&[&T]) -> bool, T : 'a { fn len(&self) -> usize { self.len } } /// A lexicographic ordered permutation based on ["Algoritm X" published by /// Donald E. Knuth.](http://www.cs.utsa.edu/~wagner/knuth/fasc2b.pdf) page 20. /// /// If order is not important, consider using [heap permutation](struct.HeapPermutationCellIter.html) /// struct instead. This struct is a bit slower (about 10%) than [heap /// permutation](struct.HeapPermutationCellIter.html) in uncontroll test environment. /// /// The algorithm work by simulate tree traversal where some branch can be /// skip altogether. This is archive by provided `t` function that take /// slice of partial result as parameter. If the partial result needed to be skip, /// return false. Otherwise, return true and the algorithm will call this function /// again when the branch is descended deeper. For example: First call to `t` may /// contain [1]. If `t` return true, it will be called again with [1, 2]. If it /// return true, and there's leaf node, cb will be called with [1, 2]. On the other hand, /// if `t` is called with [1, 3] and it return false, it won't call the callback. /// If `t` is called with [4] and it return false, it won't try to traverse deeper even /// if there're [4, 5], or [4, 6]. It will skip altogether and call `t` with [7]. /// The process goes on until every branch is traversed. pub struct XPermutationCellIter<'a, F, T> where F : FnMut(&[&T]) -> bool, T : 'a { a : Vec<usize>, data : &'a [T], k : usize, l : Vec<usize>, len : usize, n : usize, p : usize, q : usize, result : Rc<RefCell<&'a mut [&'a T]>>, t: F, u : Vec<usize>, } impl<'a, F, T> XPermutationCellIter<'a, F, T> where F : FnMut(&[&T]) -> bool, T : 'a { /// Construct new XPermutationIterator object. /// /// # Parameters /// - `data : &[T]` - A data used for generate permutation. /// - `result : Rc<RefCell<&mut [&T]>>` - A result container. /// It'll be overwritten on each call to `next` /// - `t : FnMut(&[&T])` - A function that if return true, will /// make algorithm continue traversing the tree. Otherwise, /// the entire branch will be skip. pub fn new(data : &'a [T], result : Rc<RefCell<&'a mut [&'a T]>>, t : F) -> XPermutationCellIter<'a, F, T> { let n = data.len(); let mut l : Vec<usize> = (0..n).map(|k| k + 1).collect(); // l[n] = 0 l.push(0); // "Algo X" X1 and X2 XPermutationCellIter { a : (0..=n).map(|v| v).collect(), data : data, k : 1, l : l, len : factorial(n), n : n, p : 0, q : 1, result : result, t : t, u : vec![0; n + 1] } } } impl<'a, F, T> Iterator for XPermutationCellIter<'a, F, T> where F : FnMut(&[&T]) -> bool, T : 'a { type Item = (); fn next(&mut self) -> Option<Self::Item> { let data = self.data; let mut result = self.result.borrow_mut(); let result_ptr = (&**result) as *const [&T]; let t = &mut self.t; if let Some(_) = _x_permutation_next_core( &mut self.a, &mut self.k, &mut self.l, self.n, &mut self.p, &mut self.q, &mut self.u, |k, q| {result[k] = &data[q]}, |k| { unsafe { t(&(*result_ptr)[0..k]) } }) { Some(()) } else { None } } } impl<'a, F, T> IteratorReset for XPermutationCellIter<'a, F, T> where F : FnMut(&[&T]) -> bool, T : 'a { fn reset(&mut self) { let n = self.data.len(); let mut l : Vec<usize> = (0..n).map(|k| k + 1).collect(); // l[n] = 0 l.push(0); self.a = (0..=n).map(|v| v).collect(); self.k = 1; self.l = l; self.p = 0; self.q = 1; self.u = vec![0; n + 1]; } } impl<'a, F, T> ExactSizeIterator for XPermutationCellIter<'a, F, T> where F : FnMut(&[&T]) -> bool, T : 'a { fn len(&self) -> usize { self.len } } /// A lexicographic ordered permutation based on ["Algoritm X" published by /// Donald E. Knuth.](http://www.cs.utsa.edu/~wagner/knuth/fasc2b.pdf) page 20. /// /// If order is not important, consider using [heap permutation](struct.HeapPermutationRefIter.html) /// struct instead. This struct is a bit slower (about 10%) than [heap /// permutation](struct.HeapPermutationRefIter.html) in uncontroll test environment. /// /// The algorithm work by simulate tree traversal where some branch can be /// skip altogether. This is archive by provided `t` function that take /// slice of partial result as parameter. If the partial result needed to be skip, /// return false. Otherwise, return true and the algorithm will call this function /// again when the branch is descended deeper. For example: First call to `t` may /// contain [1]. If `t` return true, it will be called again with [1, 2]. If it /// return true, and there's leaf node, cb will be called with [1, 2]. On the other hand, /// if `t` is called with [1, 3] and it return false, it won't call the callback. /// If `t` is called with [4] and it return false, it won't try to traverse deeper even /// if there're [4, 5], or [4, 6]. It will skip altogether and call `t` with [7]. /// The process goes on until every branch is traversed. pub struct XPermutationRefIter<'a, F, T> where F : FnMut(&[&T]) -> bool, T : 'a { a : Vec<usize>, data : &'a [T], k : usize, l : Vec<usize>, len : usize, n : usize, p : usize, q : usize, result : &'a mut [&'a T], t: F, u : Vec<usize>, } impl<'a, F, T> XPermutationRefIter<'a, F, T> where F : FnMut(&[&T]) -> bool, T : 'a { /// Construct new XPermutationIterator object. /// /// # Parameters /// - `data : &[T]` - A data used for generate permutation. /// - `result : Rc<RefCell<&mut [&T]>>` - A result container. /// It'll be overwritten on each call to `next` /// - `t : FnMut(&[&T])` - A function that if return true, will /// make algorithm continue traversing the tree. Otherwise, /// the entire branch will be skip. pub unsafe fn new(data : &'a [T], result : *mut [&'a T], t : F) -> XPermutationRefIter<'a, F, T> { let n = data.len(); let mut l : Vec<usize> = (0..n).map(|k| k + 1).collect(); // l[n] = 0 l.push(0); // "Algo X" X1 and X2 XPermutationRefIter { a : (0..=n).map(|v| v).collect(), data : data, k : 1, l : l, len : factorial(n), n : n, p : 0, q : 1, result : &mut *result, t : t, u : vec![0; n + 1] } } } impl<'a, F, T> Iterator for XPermutationRefIter<'a, F, T> where F : FnMut(&[&T]) -> bool, T : 'a { type Item = (); fn next(&mut self) -> Option<Self::Item> { let data = self.data; let result = &mut *self.result; let result_ptr = (&*result) as *const [&T]; let t = &mut self.t; if let Some(_) = _x_permutation_next_core( &mut self.a, &mut self.k, &mut self.l, self.n, &mut self.p, &mut self.q, &mut self.u, |k, q| {result[k] = &data[q]}, |k| { unsafe { t(&(*result_ptr)[0..k]) } }) { Some(()) } else { None } } } impl<'a, F, T> IteratorReset for XPermutationRefIter<'a, F, T> where F : FnMut(&[&T]) -> bool, T : 'a { fn reset(&mut self) { let n = self.data.len(); let mut l : Vec<usize> = (0..n).map(|k| k + 1).collect(); // l[n] = 0 l.push(0); self.a = (0..=n).map(|v| v).collect(); self.k = 1; self.l = l; self.p = 0; self.q = 1; self.u = vec![0; n + 1]; } } impl<'a, F, T> ExactSizeIterator for XPermutationRefIter<'a, F, T> where F : FnMut(&[&T]) -> bool, T : 'a { fn len(&self) -> usize { self.len } } /// Generate a cartesian product on itself in an iterator style. /// The struct implement `Iterator` trait so it can be used in `Iterator` /// style. The struct provide [into_iter()](#method.into_iter()) function /// that return itself. /// /// # Example /// ``` /// use permutator::SelfCartesianProductIterator; /// use std::time::Instant; /// let data : &[usize] = &[1, 2, 3]; /// let n = 3; /// let cart = SelfCartesianProductIterator::new(&data, n); /// let mut counter = 0; /// let timer = Instant::now(); /// /// for p in cart { /// // println!("{:?}", p); /// counter += 1; /// } /// /// // or functional style like the line below /// // cart.into_iter().for_each(|p| {/* do something iterative style */}); /// /// assert_eq!(data.len().pow(n as u32), counter); /// println!("Total {} products done in {:?}", counter, timer.elapsed()); /// ``` pub struct SelfCartesianProductIterator<'a, T> where T : 'a { c : Vec<usize>, domain : &'a [T], exhausted : bool, i : usize, n : usize, result : Vec<&'a T> } impl<'a, T> SelfCartesianProductIterator<'a, T> where T : 'a { /// Create a new Cartesian product iterator that create a product on /// itself `n` times. /// # Parameters /// - `domain` A slice of domains to create a cartesian product between /// each domain inside it. /// - `n` the size of product. For example `n = 3` means create /// a cartesian product over `domain` paremeter 3 times. /// This is equals to create a `domains` contains /// cloned `domain` 3 time. /// # Return /// An object that can be iterate over in iterator style. pub fn new(domain : &'a[T], n : usize) -> SelfCartesianProductIterator<'a, T> { SelfCartesianProductIterator { c : vec![0; domain.len()], domain : domain, exhausted : false, i : 0, n : n, result : vec![&domain[0]; n] } } /// Consume itself and return without modify it. /// Typical usecase is `for p in ref_to_this.into_iter() {}` /// or `ref_to_this.into_iter().for_each(|p| {/* Do something with product */});` pub fn into_iter(self) -> Self { self } } impl<'a, T> Iterator for SelfCartesianProductIterator<'a, T> { type Item = Vec<&'a T>; /// Each iteration return a new Vec contains borrowed element inside /// an Option. The result can be collected by using `collect` method /// from `Iterator` trait. /// /// Return None when exhausted. fn next(&mut self) -> Option<Vec<&'a T>> { let result = &mut self.result; let domain = self.domain; _cartesian_next_core( &mut self.i, &mut self.c, &mut self.exhausted, self.n, #[inline(always)] |_| { domain.len() }, #[inline(always)] |i, j| { result[i] = &domain[j]; } ); if self.exhausted { None } else { self.i -= 1; // rewind `i` back to last domain Some(result.to_owned()) } } } impl<'a, T> IteratorReset for SelfCartesianProductIterator<'a, T> { fn reset(&mut self) { self.c = vec![0; self.n]; self.exhausted = false; self.i = 0; } } impl<'a, T> ExactSizeIterator for SelfCartesianProductIterator<'a, T> { fn len(&self) -> usize { self.n } } /// Generate a cartesian product on itself in an iterator style. /// The struct implement `Iterator` trait so it can be used in `Iterator` /// style. The struct provide [into_iter()](#method.into_iter()) function /// that return itself. /// /// # Example /// ``` /// use permutator::SelfCartesianProductCellIter; /// use std::cell::RefCell; /// use std::rc::Rc; /// use std::time::Instant; /// let data : &[usize] = &[1, 2, 3]; /// let n = 3; /// let result : &mut[&usize] = &mut vec![&data[0]; n]; /// let shared = Rc::new(RefCell::new(result)); /// let cart = SelfCartesianProductCellIter::new(&data, n, Rc::clone(&shared)); /// let mut counter = 0; /// let timer = Instant::now(); /// /// for _ in cart { /// // println!("{:?}", &*shared.borrow()); /// counter += 1; /// } /// /// // or functional style like the line below /// // cart.into_iter().for_each(|_| {/* do something iterative style */}); /// /// assert_eq!(data.len().pow(n as u32), counter); /// println!("Total {} products done in {:?}", counter, timer.elapsed()); /// ``` pub struct SelfCartesianProductCellIter<'a, T> where T : 'a { c : Vec<usize>, domain : &'a [T], exhausted : bool, i : usize, n : usize, result : Rc<RefCell<&'a mut [&'a T]>> } impl<'a, T> SelfCartesianProductCellIter<'a, T> where T : 'a { /// Create a new Cartesian product iterator that create a product on /// itself `n` times. /// # Parameters /// - `domain` A slice of domains to create a cartesian product between /// each domain inside it. /// This is equals to create a `domains` contains /// cloned `domain` 3 time. /// - `n` the size of product. For example `n = 3` means create /// a cartesian product over `domain` paremeter 3 times. /// - `result` an Rc<RefCell<&mut[&T]>> to store each product /// # Return /// An object that can be iterate over in iterator style. pub fn new(domain : &'a[T], n : usize, result : Rc<RefCell<&'a mut [&'a T]>>) -> SelfCartesianProductCellIter<'a, T> { SelfCartesianProductCellIter { c : vec![0; domain.len()], domain : domain, exhausted : false, i : 0, n : n, result : Rc::clone(&result) } } /// Consume itself and return without modify it. /// Typical usecase is `for p in ref_to_this.into_iter() {}` /// or `ref_to_this.into_iter().for_each(|p| {/* Do something with product */});` pub fn into_iter(self) -> Self { self } } impl<'a, T> Iterator for SelfCartesianProductCellIter<'a, T> { type Item = (); /// Each iteration return a new Vec contains borrowed element inside /// an Option. The result can be collected by using `collect` method /// from `Iterator` trait. /// /// Return None when exhausted. fn next(&mut self) -> Option<()> { let mut result = self.result.borrow_mut(); let domain = self.domain; _cartesian_next_core( &mut self.i, &mut self.c, &mut self.exhausted, self.n, #[inline(always)] |_| { domain.len() }, #[inline(always)] |i, j| { result[i] = &domain[j]; } ); if self.exhausted { None } else { self.i -= 1; // rewind `i` back to last domain Some(()) } } } impl<'a, T> IteratorReset for SelfCartesianProductCellIter<'a, T> { fn reset(&mut self) { self.c = vec![0; self.n]; self.exhausted = false; self.i = 0; } } impl<'a, T> ExactSizeIterator for SelfCartesianProductCellIter<'a, T> { fn len(&self) -> usize { self.n } } /// Generate a cartesian product on itself in an iterator style. /// The struct implement `Iterator` trait so it can be used in `Iterator` /// style. The struct provide [into_iter()](#method.into_iter()) function /// that return itself. /// /// # Example /// ``` /// use permutator::SelfCartesianProductRefIter; /// use std::time::Instant; /// let data : &[usize] = &[1, 2, 3]; /// let n = 3; /// let result : &mut[&usize] = &mut vec![&data[0]; n]; /// let shared = result as *mut[&usize]; /// /// unsafe { /// let cart = SelfCartesianProductRefIter::new(&data, n, result); /// let mut counter = 0; /// let timer = Instant::now(); /// /// for _ in cart { /// // println!("{:?}", &*shared); /// counter += 1; /// } /// /// // or functional style like the line below /// // cart.into_iter().for_each(|_| {/* do something iterative style */}); /// /// assert_eq!(data.len().pow(n as u32), counter); /// println!("Total {} products done in {:?}", counter, timer.elapsed()); /// } /// ``` pub struct SelfCartesianProductRefIter<'a, T> where T : 'a { c : Vec<usize>, domain : &'a [T], exhausted : bool, i : usize, n : usize, result : &'a mut [&'a T] } impl<'a, T> SelfCartesianProductRefIter<'a, T> where T : 'a { /// Create a new Cartesian product iterator that create a product on /// itself `n` times. /// # Parameters /// - `domain` A slice of domains to create a cartesian product between /// each domain inside it. /// This is equals to create a `domains` contains /// cloned `domain` 3 time. /// - `n` the size of product. For example `n = 3` means create /// a cartesian product over `domain` paremeter 3 times. /// - `result` *mut[&T] to store each product /// # Return /// An object that can be iterate over in iterator style. pub unsafe fn new(domain : &'a[T], n : usize, result : * mut [&'a T]) -> SelfCartesianProductRefIter<'a, T> { SelfCartesianProductRefIter { c : vec![0; domain.len()], domain : domain, exhausted : false, i : 0, n : n, result : &mut *result } } /// Consume itself and return without modify it. /// Typical usecase is `for p in ref_to_this.into_iter() {}` /// or `ref_to_this.into_iter().for_each(|p| {/* Do something with product */});` pub fn into_iter(self) -> Self { self } } impl<'a, T> Iterator for SelfCartesianProductRefIter<'a, T> { type Item = (); /// Each iteration return a new Vec contains borrowed element inside /// an Option. The result can be collected by using `collect` method /// from `Iterator` trait. /// /// Return None when exhausted. fn next(&mut self) -> Option<()> { let result = &mut self.result; let domain = self.domain; _cartesian_next_core( &mut self.i, &mut self.c, &mut self.exhausted, self.n, #[inline(always)] |_| { domain.len() }, #[inline(always)] |i, j| { result[i] = &domain[j]; } ); if self.exhausted { None } else { self.i -= 1; // rewind `i` back to last domain Some(()) } } } impl<'a, T> IteratorReset for SelfCartesianProductRefIter<'a, T> { fn reset(&mut self) { self.c = vec![0; self.n]; self.exhausted = false; self.i = 0; } } impl<'a, T> ExactSizeIterator for SelfCartesianProductRefIter<'a, T> { fn len(&self) -> usize { self.n } } /// Create a cartesian product out of `T`. /// For example, /// - `T` can be a slice of slices so the product can /// be created between all the slices. /// - `T` can be a pair of slice to slices and Rc<RefCell<>> contains /// a mutable product from slices. /// /// # Examples /// - Create a cartesian product and return it as new owned value /// ``` /// use std::time::Instant; /// use permutator::CartesianProduct; /// /// let mut counter = 0; /// let timer = Instant::now(); /// let data : &[&[u8]]= &[&[1, 2, 3], &[4, 5, 6], &[7, 8, 9]]; /// /// data.cart_prod().for_each(|p| { /// counter += 1; /// }); /// /// assert_eq!(data.iter().fold(1, |cum, domain| {cum * domain.len()}), counter); /// println!("Total {} products done in {:?}", counter, timer.elapsed()); /// ``` /// - Create a cartesian product and return result inside /// Rc<RefCell<>> /// ``` /// use std::cell::RefCell; /// use std::rc::Rc; /// use std::time::Instant; /// use permutator::CartesianProduct; /// /// let mut counter = 0; /// let timer = Instant::now(); /// let data : &[&[u8]]= &[&[1, 2, 3], &[4, 5, 6], &[7, 8, 9]]; /// let mut result = vec![&data[0][0]; data.len()]; /// let shared = Rc::new(RefCell::new(result.as_mut_slice())); /// /// (data, Rc::clone(&shared)).cart_prod().for_each(|_| { /// counter += 1; /// }); /// /// assert_eq!(data.iter().fold(1, |cum, domain| {cum * domain.len()}), counter); /// println!("Total {} products done in {:?}", counter, timer.elapsed()); /// ``` pub trait CartesianProduct<'a> { type Producer : Iterator; /// Create a cartesian product producer which /// can be used to iterate over each product. fn cart_prod(&'a self) -> Self::Producer; } impl<'a, T> CartesianProduct<'a> for [&'a [T]] where T : 'a { type Producer = CartesianProductIterator<'a, T>; fn cart_prod(&'a self) -> Self::Producer { CartesianProductIterator::new(self) } } impl<'a, T> CartesianProduct<'a> for Vec<&'a [T]> where T : 'a { type Producer = CartesianProductIterator<'a, T>; fn cart_prod(&'a self) -> Self::Producer { CartesianProductIterator::new(self) } } /// A type that represent a cartesian product of the slice /// over slices and return result into Rc<RefCell<&mut [&T]>> /// by using [CartesianProductCellIter](trait.CartesianProductCellIter.html) /// /// # Format /// 1. A mutable slice of slices. /// It's a domains to of a cartesian product operation. /// 2. An Rc<RefCell<&mut[&T]>. /// It's a result container. pub type CartesianProductIntoCellParams<'a, T> = (&'a [&'a [T]], Rc<RefCell<&'a mut[&'a T]>>); impl<'a, 'b: 'a, T> CartesianProduct<'a> for CartesianProductIntoCellParams<'b, T> where T : 'b { type Producer = CartesianProductCellIter<'b, T>; fn cart_prod(&'a self) -> Self::Producer { CartesianProductCellIter::new(self.0, Rc::clone(&self.1)) } } /// A type that used exclusively for [trait CartesianProduct](trait.CartesianProduct.html). /// It return [CartesianProductRefIter](struct.CartesianProductRefIter.html). /// /// It's a tuple where first element is a slice contains slices represents a domains /// of Cartesian product function. The second element is a mutable pointer to a slice which /// will be used to store each product. /// /// # Format /// 1. A mutable slice of slices. /// It's a domains to of a cartesian product operation. /// 2. A pointer to mutable slice of borrowed value. /// It's a result container. pub type CartesianProductIntoRefParams<'a, T> = (&'a [&'a [T]], *mut [&'a T]); /// An implementation for convenient use of [CartesianProductRefIter](struct.CartesianProductRefIter.html) /// # Warning /// It hid unsafe object instantiation of [CartesianProductRefIter](struct.CartesianProductRefIter.html#method.new) /// from user but all unsafe conditions are still applied as long as /// the the life of object itself. /// impl<'a, 'b: 'a, T> CartesianProduct<'a> for CartesianProductIntoRefParams<'b, T> where T : 'b { type Producer = CartesianProductRefIter<'b, T>; fn cart_prod(&'a self) -> Self::Producer { unsafe { CartesianProductRefIter::new(self.0, self.1) } } } /// A type that used exclusively for [trait CartesianProduct](trait.CartesianProduct.html). /// It return [SelfCartesianProductIterator](struct.SelfCartesianProductIterator.html). /// /// # Format /// 1. A slice of T. /// 2. How many time to create a product on slice pub type SelfCartesianProduct<'a, T> = (&'a [T], usize); impl<'a, 'b : 'a, T> CartesianProduct<'a> for SelfCartesianProduct<'b, T> where T : 'b { type Producer = SelfCartesianProductIterator<'b, T>; fn cart_prod(&'a self) -> Self::Producer { SelfCartesianProductIterator::new(self.0, self.1) } } /// A type that used exclusively for [trait CartesianProduct](trait.CartesianProduct.html). /// It return [SelfCartesianProductCellIter](struct.SelfCartesianProductCellIter.html). /// /// # Format /// 1. A slice of T. /// 2. How many time to create a product on slice /// 3. An Rc<RefCell<&mut [T]>> to store each product on each iteration. pub type SelfCartesianProductIntoCellParams<'a, T> = (&'a [T], usize, Rc<RefCell<&'a mut [&'a T]>>); impl<'a, 'b : 'a, T> CartesianProduct<'a> for SelfCartesianProductIntoCellParams<'b, T> where T : 'b { type Producer = SelfCartesianProductCellIter<'b, T>; fn cart_prod(&'a self) -> Self::Producer { SelfCartesianProductCellIter::new(self.0, self.1, Rc::clone(&self.2)) } } /// A type that used exclusively for [trait CartesianProduct](trait.CartesianProduct.html). /// It return [SelfCartesianProductRefIter](struct.SelfCartesianProductRefIter.html). /// /// # Format /// 1. A slice of T. /// 2. How many time to create a product on slice /// 3. A mutable pointer to a slice of ref T pub type SelfCartesianProductIntoRefParams<'a, T> = (&'a [T], usize, *mut [&'a T]); /// An implementation for convenient use of [SelfCartesianProductRefIter](struct.SelfCartesianProductRefIter.html) /// # Warning /// It hid unsafe object instantiation of [SelfCartesianProductRefIter](struct.SelfCartesianProductRefIter.html#method.new) /// from user but all unsafe conditions are still applied as long as /// the life of object itself. impl<'a, 'b : 'a, T> CartesianProduct<'a> for SelfCartesianProductIntoRefParams<'b, T> where T : 'b { type Producer = SelfCartesianProductRefIter<'b, T>; fn cart_prod(&'a self) -> Self::Producer { unsafe { SelfCartesianProductRefIter::new(self.0, self.1, self.2) } } } /// Create a combination out of `T` /// Normally, it take a `[T]` or `Vec<T>` to create a combination. /// /// # Example /// ``` /// use permutator::Combination; /// let data = [1, 2, 3, 4, 5]; /// data.combination(3).for_each(|c| { /// // called multiple times. /// // Each call have [1, 2, 3], [1, 2, 4], [1, 3, 4], [2, 3, 4] /// // [1, 2, 5], [1, 3, 5], [2, 3, 5], [1, 4, 5], [2, 4, 5], /// // and [3, 4, 5] respectively. /// println!("{:?}", c); /// }); /// ``` /// /// See [Example implementation](trait.Combination.html#foreign-impls) on /// foreign type. pub trait Combination<'a> { type Combinator : Iterator; /// Create a family of [LargeCombinationIterator](struct.LargeCombinationIterator.html) /// of `k` size out of `self`. /// See [LargeCombinationIterator](struct.LargeCombinationIterator.html) for /// how to use [LargeCombinationIterator](struct.LargeCombinationIterator.html) /// /// # Return /// A new family of [LargeCombinationIterator<T>](struct.LargeCombinationIterator.html) fn combination(&'a self, k : usize) -> Self::Combinator; } /// An implementation for convenient use of [LargeCombinationIterator](struct.LargeCombinationIterator.html) impl<'a, T> Combination<'a> for [T] where T : 'a { type Combinator = LargeCombinationIterator<'a, T>; fn combination(&'a self, k : usize) -> LargeCombinationIterator<'a, T> { LargeCombinationIterator::new(self, k) } } /// An implementation for convenient use of [LargeCombinationIterator](struct.LargeCombinationIterator.html) impl<'a, T> Combination<'a> for Vec<T> where T : 'a { type Combinator = LargeCombinationIterator<'a, T>; fn combination(&'a self, k : usize) -> LargeCombinationIterator<'a, T> { LargeCombinationIterator::new(self, k) } } /// A pair of source and sink to get a sharable combination. /// /// It's tuple contains a source data to generate a combination /// and a sink to temporary store each combination. /// /// This type is use exclusively with [trait Combination](trait.Combination.html#implementors) /// /// # Format /// 1. First value in tuple is a `&'a [T]` - /// It's a source data to generate a combination. /// 2. Second value in tuple is an Rc<RefCell<&'a mut[&'a T]>>` - /// It's a sink to temporary store each combination. pub type CombinationIntoCellParams<'a, T> = (&'a [T], Rc<RefCell<&'a mut[&'a T]>>); /// An implementation for convenient use of [LargeCombinationCellIter](struct.LargeCombinationCellIter.html) impl<'a, 'b : 'a, T> Combination<'a> for CombinationIntoCellParams<'b, T> { type Combinator = LargeCombinationCellIter<'b, T>; fn combination(&'a self, k : usize) -> LargeCombinationCellIter<'b, T> { LargeCombinationCellIter::new(self.0, k, Rc::clone(&self.1)) } } /// A pair of source and sink to get a sharable combination. /// /// It's tuple contains a source data to generate a combination /// and a sink to temporary store each combination. /// /// This type is use exclusively with [trait Combination](trait.Combination.html#implementors) /// /// # Format /// 1. A mutable slice of slices. /// It's a domains to of a cartesian product operation. /// 2. A pointer to mutable slice of borrowed value. /// It's a result container. pub type CombinationIntoRefParams<'a, T> = (&'a [T], * mut[&'a T]); /// An implementation for convenient use of [LargeCombinationRefIter](struct.LargeCombinationRefIter.html) /// # Warning /// It hid unsafe object instantiation of [LargeCombinationRefIter](struct.LargeCombinationRefIter.html#method.new) /// from user but all unsafe conditions are still applied as long as /// the life of object itself. impl<'a, 'b : 'a, T> Combination<'a> for CombinationIntoRefParams<'b, T> { type Combinator = LargeCombinationRefIter<'b, T>; fn combination(&'a self, k : usize) -> LargeCombinationRefIter<'b, T> { unsafe { LargeCombinationRefIter::new(self.0, k, self.1) } } } /// Create a permutation iterator that permute data in place. /// Built-in implementation return an object of /// [HeapPermutation](struct.HeapPermutationIterator.html) for slice/array and Vec. /// It return an object of [HeapPermutationCellIter](struct.HeapPermutationCellIter.html) /// on data type of `Rc<RefCell<&mut [T]>>`. /// /// # Example /// For typical permutation: /// ``` /// use permutator::Permutation; /// let mut data = vec![1, 2, 3]; /// data.permutation().for_each(|p| { /// // call multiple times. It'll print [1, 2, 3], [2, 1, 3], [3, 1, 2], /// // [1, 3, 2], [2, 3, 1], and [3, 2, 1] respectively. /// println!("{:?}", p); /// }); /// ``` /// For k-permutation: /// ``` /// use permutator::{Combination, Permutation}; /// let data = [1, 2, 3, 4, 5]; /// let k = 3; /// /// data.combination(k).for_each(|mut combination| { /// // print the first combination /// combination.permutation().for_each(|permuted| { /// // print permutation of each combination /// println!("{:?}", permuted); /// }); /// }); /// // All k-permutation printed /// ``` /// /// # See /// - [HeapPermutation](struct.HeapPermutationIterator.html) for more detail /// about how to use [HeapPermutation](struct.HeapPermutationIterator.html). /// - [HeapPermutationCellIter](struct.HeapPermutationCellIter.html) for more detail /// about how to use [HeapPermutationCellIter](struct.HeapPermutationCellIter.html) /// - [Example implementation](trait.Permutation.html#foreign-impls) on foreign type /// /// # Breaking change from 0.3.x to 0.4 /// Since version 0.4.0, the first result return by this iterator /// will be the original value pub trait Permutation<'a> { /// A permutation generator for a collection of data. /// # See /// - [Foreign implementation for an example different return type](trait.Permutation.html#foreign-impls) type Permutator : Iterator; /// Create a permutation based on Heap's algorithm. /// It return [HeapPermutation](struct.HeapPermutationIterator.html) object. fn permutation(&'a mut self) -> Self::Permutator; } /// Generate permutation on an array or slice of T /// It return mostly similar to [HeapPermutation](struct.HeapPermutationIterator.html) /// but it include an original value as first value return by `Iterator`. /// /// # Breaking change from 0.3.x to 0.4 /// Since version 0.4.0, the first result return by this iterator /// will be the original value impl<'a, T> Permutation<'a> for [T] where T : 'a + Clone { /// Use [HeapPermutation](struct.HeapPermutationIterator.html) /// as permutation generator type Permutator = Chain<Once<Vec<T>>, HeapPermutationIterator<'a, T>>; fn permutation(&'a mut self) -> Chain<Once<Vec<T>>, HeapPermutationIterator<T>> { let origin = once(self.to_owned()); origin.into_iter().chain(HeapPermutationIterator::new(self)) } } /// Generate permutation on a Vec of T /// It return mostly similar to [HeapPermutation](struct.HeapPermutationIterator.html) /// but it include an original value as first value return by `Iterator`. /// /// # Breaking change from 0.3.x to 0.4 /// Since version 0.4.0, the first result return by this iterator /// will be the original value impl<'a, T> Permutation<'a> for Vec<T> where T : 'a + Clone { /// Use [HeapPermutation](struct.HeapPermutationIterator.html) /// as permutation generator type Permutator = Chain<Once<Vec<T>>, HeapPermutationIterator<'a, T>>; fn permutation(&'a mut self) -> Chain<Once<Vec<T>>, HeapPermutationIterator<T>> { let origin = once(self.to_owned()); origin.into_iter().chain(HeapPermutationIterator::new(self)) } } /// Generate a sharable permutation inside `Rc<RefCell<&mut [T]>>` /// It return [HeapPermutationCellIter](struct.HeapPermutationCellIter.html) /// but it include an original value as first value return by `Iterator`. /// /// # Breaking change from 0.3.x to 0.4 /// Since version 0.4.0, the first result return by this iterator /// will be the original value impl<'a, T> Permutation<'a> for Rc<RefCell<&'a mut[T]>> where T :'a { /// Use [HeapPermutationCellIter](struct.HeapPermutationCellIter.html) /// as permutation generator type Permutator = Chain<Once<()>, HeapPermutationCellIter<'a, T>>; fn permutation(&'a mut self) -> Chain<Once<()>, HeapPermutationCellIter<T>> { let original = once(()); original.into_iter().chain( HeapPermutationCellIter { c : vec![0; self.borrow().len()], data : Rc::clone(self), i : 0 } ) } } /// Generate permutation a mutable pointer to slice of T /// It return [HeapPermutation](struct.HeapPermutationRefIter.html) /// but it include an original value as first value return by `Iterator`. /// /// # Warning /// This implementation hid unsafe inside the permutation function but /// doesn't provide any additional safety. /// User need to treat the return object as unsafe. /// /// # Breaking change from 0.3.x to 0.4 /// Since version 0.4.0, the first result return by this iterator /// will be the original value impl<'a, T> Permutation<'a> for *mut [T] where T : 'a + Clone { /// Use [HeapPermutation](struct.HeapPermutationIterator.html) /// as permutation generator type Permutator = Chain<Once<()>, HeapPermutationRefIter<'a, T>>; fn permutation(&'a mut self) -> Chain<Once<()>, HeapPermutationRefIter<T>> { let original = once(()); unsafe { original.into_iter().chain( HeapPermutationRefIter { c : vec![0; (**self).len()], data : &mut (**self), i : 0 } ) } } } /// A pair of parameter that allow `Permutation` trait /// to create [k-permutation iterator](struct.KPermutationIterator.html) from it. /// /// This type is used exclusively in [trait Permutation](trait.Permutation.html#implementors) /// /// # Format /// 1. First value in tuple is `&'a [T]`. /// It's a source data to generate k-permutation. /// 2. Second value in tuple is `usize`. /// It's `k` size which shall be less than `n` /// where `n` is a length of the first value. pub type KPermutationParams<'a, T> = (&'a [T], usize); impl<'a, T> Permutation<'a> for KPermutationParams<'a, T> { type Permutator = KPermutationIterator<'a, T>; fn permutation(&'a mut self) -> KPermutationIterator<'a, T> { KPermutationIterator::new(self.0, self.1) } } /// A tuples of 3 parameters that allow `Permutation` trait /// to create [k-permutation iterator](struct.KPermutationCellIter.html) from it. /// /// This type is used exclusively in [trait Permutation](trait.Permutation.html#implementors) /// /// # Format /// 1. First value in tuple is `&'a [T]`. /// It's a source data to generate k-permutation. /// 2. Second value in tuple is `usize`. /// It's `k` size which shall be less than `n` /// where `n` is a length of the first value. /// 3. Third value in tuple is `Rc<RefCell<&mut[&T]>>` /// It's a sink of operation. It's a ref to each permutation result. pub type KPermutationIntoCellParams<'a, T> = (&'a [T], usize, Rc<RefCell<&'a mut [&'a T]>>); impl<'a, 'b : 'a, T> Permutation<'a> for KPermutationIntoCellParams<'b, T> { type Permutator = KPermutationCellIter<'b, T>; fn permutation(&'a mut self) -> Self::Permutator { KPermutationCellIter::new(self.0, self.1, Rc::clone(&self.2)) } } /// A tuple of 3 parameters that allow `Permutation` trait /// to create [k-permutation ref iterator](struct.KPermutationRefIterator.html) from it. /// /// This type is used exclusively in [trait Permutation](trait.Permutation.html#implementors) /// /// # Format /// 1. First value in tuple is `&'a [T]`. /// It's a source data to generate k-permutation. /// 2. Second value in tuple is `usize`. /// It's `k` size which shall be less than `n` /// where `n` is a length of the first value. /// 3. Third value in tule i `*mut [&T]` /// It's a sink that store a ref to each permutation. pub type KPermutationIntoRefParams<'a, T> = (&'a [T], usize, *mut [&'a T]); impl<'a, 'b : 'a, T> Permutation<'a> for KPermutationIntoRefParams<'b, T> { type Permutator = KPermutationRefIter<'b, T>; fn permutation(&'a mut self) -> Self::Permutator { unsafe { KPermutationRefIter::new(self.0, self.1, &mut *self.2) } } } // if GAT is supported by Rust. This is probably how Lex-ordered permutation trait // should look like. // // struct LexicographicallyOrdered; // // impl<'a, 'b : 'a, T> Permutation<'a> for (&'b [T], LexicographicallyOrdered) // { // type Permutator<F> = XPermutationIterator<'a, F, T>; // // fn permutation(&'a mut self) -> Self::Permutator { // let (d, ..) = self; // XPermutationIterator::new(d, |_| true) // } // } /// # Deprecated /// Superseded by algorithm published by Stanford university /// Generate binary representation of combination inside /// usize. It mutate variable in place. /// It'll return None when there's no further possible /// combination by given x. #[allow(unused)] fn gosper_combination(x : &mut u128) -> Option<()> { let u = *x & x.overflowing_neg().0; // get LSB that has 1 let v = u + *x; // Add LSB to x if v == 0 { return None } *x = v + (((v ^ *x) / u) >> 2); Some(()) } /// Generate binary representation of combination by /// using algorithm published by Stanford university. /// The different from original Gosper algorithm is /// it eliminate divide operation by using built in /// trailing_zeros function. /// /// # Limitation /// Gosper algorithm need to know the MSB (most significant bit). /// The current largest known MSB data type is u128. /// This make the implementation support up to 128 elements slice. /// /// Reference: /// - [Compute the lexicographically next bit permutation](http://graphics.stanford.edu/~seander/bithacks.html#NextBitPermutation) #[inline(always)] fn stanford_combination(x: &mut u128) { let t = *x | (*x - 1); // get x and set LSB set to 1 // Next set to 1 the most significant bit to change, // set to 0 the least significant ones, and add the necessary 1 bits. *x = (t + 1) | (((!t & (!t).overflowing_neg().0) - 1) >> (x.trailing_zeros() + 1)); } /// Calculate factorial from given value. pub fn factorial<T>(n: T) -> T where T : PrimInt + Unsigned + Product { num::range(T::one(), n + T::one()).product() } /// Calculate factorial for two factorial division. /// It'll return 1 if numerator is smaller or equals to denominator. /// Otherwise, it'll short circuit the calculation by calculate only /// the undivided remainder. /// /// # Examples /// ``` /// use permutator::divide_factorial; /// /// // calculate 5!/3! /// divide_factorial(5u8, 3u8); // return 5 * 4 = 20 /// // calculate 3!/5! /// divide_factorial(3u32, 5u32); // return 1. /// // calculate 5!/5! /// divide_factorial(5u16, 5u16); // return 1. /// ``` pub fn divide_factorial<T>(numerator: T, denominator: T) -> T where T : PrimInt + Unsigned + Product { if numerator < denominator { T::one() } else if denominator < numerator { num::range_inclusive(denominator + T::one(), numerator).product() } else { T::one() } } /// Calculate two factorial multiply on each other. /// It'll try to reduce calculation time by calculate the /// common value only once. /// /// # Examples /// ``` /// use permutator::multiply_factorial; /// // 5! * 4! /// multiply_factorial(5u32, 4u32); // calculate 4! and power it by 2 then multiply by 5. /// multiply_factorial(4u32, 5u32); // perform similar to above step. /// multiply_factorial(5u128, 5u128); // calculate 5! and power it by 2. /// ``` pub fn multiply_factorial<T>(fact1: T, fact2: T) -> T where T : PrimInt + Unsigned + Product { if fact1 < fact2 { let common = factorial(fact1); common.pow(2) * num::range_inclusive(fact1 + T::one(), fact2).product() } else if fact2 < fact1 { let common = factorial(fact2); common.pow(2) * num::range_inclusive(fact2 + T::one(), fact1).product() } else { return factorial(fact1).pow(2); } } /// Initiate a first combination along with Gospel's map for further /// combination calculation. /// The name k_set refer to the use case of k-permutation. /// It's first k combination of data `d` inside single set. fn create_k_set<T>(d : &[T], width : usize) -> (Vec<&T>, u128) { let mask = (1 << width) - 1; let mut copied_mask = mask; let mut i = 0; let mut subset = Vec::new(); while copied_mask > 0 { if copied_mask & 1 == 1 { subset.push(&d[i]); } i += 1; copied_mask >>= 1; } (subset, mask) } /// Similar to create_k_set but return result through unsafe pointer /// # Parameters /// - `d` A raw data to get a subset `k` /// - `width` A size of subset, AKA `k` /// - `result` A mutable pointer that will be stored `k` subset /// - `mask` A gosper bit map /// # See /// - [create_k_set](fn.create_k_set.html) unsafe fn unsafe_create_k_set<'a, T>(d : &'a[T], width : usize, result : *mut [&'a T], mask : &mut u128) { *mask = (1 << width) - 1; let mut copied_mask = *mask; let mut i = 0; let mut j = 0; while copied_mask > 0 { if copied_mask & 1 == 1 { (*result)[j] = &d[i]; j += 1; } i += 1; copied_mask >>= 1; } } /// Similar to create_k_set but return result through Rc<RefCell<&'a mut[&'a T]>> /// # Parameters /// - `d` A raw data to get a subset `k` /// - `width` A size of subset, AKA `k` /// - `result` An ref to Rc<RefCell<>> storing mutable slice that will be stored `k` subset /// - `mask` A gosper bit map /// # See /// - [create_k_set](fn.create_k_set.html) fn create_k_set_in_cell<'a, T>(d : &'a[T], width : usize, result : &Rc<RefCell<&'a mut[&'a T]>>, mask : &mut u128) { *mask = (1 << width) - 1; let mut copied_mask = *mask; let mut i = 0; let mut j = 0; while copied_mask > 0 { if copied_mask & 1 == 1 { result.borrow_mut()[j] = &d[i]; j += 1; } i += 1; copied_mask >>= 1; } } /// Similar to create_k_set but return result through Rc<RefCell<&'a mut[&'a T]>> /// # Parameters /// - `d` A raw data to get a subset `k` /// - `width` A size of subset, AKA `k` /// - `result` An ref to Rc<RefCell<>> storing mutable slice that will be stored `k` subset /// - `mask` A gosper bit map /// # See /// - [create_k_set](fn.create_k_set.html) fn create_k_set_sync<'a, T>(d : &'a[T], width : usize, result : &Arc<RwLock<Vec<&'a T>>>, mask : &mut u128) { *mask = (1 << width) - 1; let mut copied_mask = *mask; let mut i = 0; let mut j = 0; while copied_mask > 0 { if copied_mask & 1 == 1 { result.write().unwrap()[j] = &d[i]; j += 1; } i += 1; copied_mask >>= 1; } } /// Swap variable into data k sized data set. It take a pair of k size data set with /// associated Gospel's map. It'll then replace all data in set with new combination /// map generated by Gospel's algorithm. The replacement is done in place. /// The function return `Some(())` to indicate that new combination replacement is done. /// If there's no further combination, it'll return `None`. #[inline(always)] fn swap_k<'a, 'b : 'a, 'c : 'b, T : 'c>(subset_map : (&'a mut [&'b T], &mut u128), d : &'c[T]) -> Option<()> { // Replace original Gosper's algorithm by using enhanced version from Stanford University instead // if let Some(_) = gosper_combination(subset_map.1) { // let mut copied_mask = *subset_map.1; // let n = d.len(); // let mut i = 0; // let mut j = 0; // while copied_mask > 0 && i < n { // if copied_mask & 1 == 1 { // subset_map.0[j] = &d[i]; // j += 1; // } // i += 1; // copied_mask >>= 1; // } // if copied_mask > 0 { // mask goes over the length of `d` now. // None // } else { // Some(()) // } // } else { // None // } stanford_combination(subset_map.1); let mut copied_mask = *subset_map.1; let n = d.len(); let mut i = 0; let mut j = 0; while copied_mask > 0 && i < n { if copied_mask & 1 == 1 { subset_map.0[j] = &d[i]; j += 1; } i += 1; copied_mask >>= 1; } if copied_mask > 0 { // mask goes over the length of `d` now. None } else { Some(()) } } /// Swap variable into data k sized data set. It take a pair of k size data set with /// associated Gospel's map. It'll then replace all data in set with new combination /// map generated by Gospel's algorithm. The replacement is done in place. /// The function return `Some(())` to indicate that new combination replacement is done. /// If there's no further combination, it'll return `None`. fn swap_k_in_cell<'a, 'b : 'a, T>(subset_map : (&Rc<RefCell<&'a mut [&'b T]>>, &mut u128), d : &'b[T]) -> Option<()> { // Replace original Gosper's algorithm by using enhanced version from Stanford University instead // if let Some(_) = gosper_combination(subset_map.1) { // let mut copied_mask = *subset_map.1; // let n = d.len(); // let mut i = 0; // let mut j = 0; // while copied_mask > 0 && i < n { // if copied_mask & 1 == 1 { // subset_map.0[j] = &d[i]; // j += 1; // } // i += 1; // copied_mask >>= 1; // } // if copied_mask > 0 { // mask goes over the length of `d` now. // None // } else { // Some(()) // } // } else { // None // } stanford_combination(subset_map.1); let mut copied_mask = *subset_map.1; let n = d.len(); let mut i = 0; let mut j = 0; while copied_mask > 0 && i < n { if copied_mask & 1 == 1 { subset_map.0.borrow_mut()[j] = &d[i]; j += 1; } i += 1; copied_mask >>= 1; } if copied_mask > 0 { // mask goes over the length of `d` now. None } else { Some(()) } } /// Swap variable into data k sized data set. It take a pair of k size data set with /// associated Gospel's map. It'll then replace all data in set with new combination /// map generated by Gospel's algorithm. The replacement is done in place. /// The function return `Some(())` to indicate that new combination replacement is done. /// If there's no further combination, it'll return `None`. fn swap_k_sync<'a, 'b : 'a, T>(subset_map : (&Arc<RwLock<Vec<&'b T>>>, &mut u128), d : &'b[T]) -> Option<()> { // Replace original Gosper's algorithm by using enhanced version from Stanford University instead // if let Some(_) = gosper_combination(subset_map.1) { // let mut copied_mask = *subset_map.1; // let n = d.len(); // let mut i = 0; // let mut j = 0; // while copied_mask > 0 && i < n { // if copied_mask & 1 == 1 { // subset_map.0[j] = &d[i]; // j += 1; // } // i += 1; // copied_mask >>= 1; // } // if copied_mask > 0 { // mask goes over the length of `d` now. // None // } else { // Some(()) // } // } else { // None // } stanford_combination(subset_map.1); let mut copied_mask = *subset_map.1; let n = d.len(); let mut i = 0; let mut j = 0; while copied_mask > 0 && i < n { if copied_mask & 1 == 1 { subset_map.0.write().unwrap()[j] = &d[i]; j += 1; } i += 1; copied_mask >>= 1; } if copied_mask > 0 { // mask goes over the length of `d` now. None } else { Some(()) } } #[cfg(test)] pub mod test { use super::*; use std::thread; use std::sync::mpsc; use std::sync::mpsc::{SyncSender, Receiver}; #[test] fn test_get_cartesian_for() { let words = ["word1", "word2", "word3"]; let result = [[&words[0], &words[0]], [&words[0], &words[1]], [&words[0], &words[2]], [&words[1], &words[0]], [&words[1], &words[1]], [&words[1], &words[2]], [&words[2], &words[0]], [&words[2], &words[1]], [&words[2], &words[2]]]; for (i, r) in result.iter().enumerate() { assert_eq!(get_cartesian_for(&words, 2, i).unwrap(), r, "Fail to get cartesian product degree 2@i={}", i); } assert_eq!(get_cartesian_for(&words, 4, 0).is_err(), true, "Unexpected no error when degree is larger than size of objects"); for (i, w) in words.iter().enumerate() { assert_eq!(get_cartesian_for(&words, 1, i).unwrap()[0], w, "Fail to get cartesian product degree 1@i={}", i); } assert_eq!(get_cartesian_for(&words, 0, 0).unwrap().len(), 0, "Fail to get cartesian product degree 0"); } #[test] fn test_get_permutation_for() { let words = ["word1", "word2", "word3"]; let result = [[&words[0], &words[1]], [&words[0], &words[2]], [&words[1], &words[0]], [&words[1], &words[2]], [&words[2], &words[0]], [&words[2], &words[1]]]; for (i, r) in result.iter().enumerate() { assert_eq!(get_permutation_for(&words, 2, i).unwrap(), r, "Fail to get permutation degree 2@i={}", i); } assert_eq!(get_permutation_for(&words, 4, 0).is_err(), true, "Unexpected no error when degree is larger than size of objects"); for (i, w) in words.iter().enumerate() { assert_eq!(get_permutation_for(&words, 1, i).unwrap()[0], w, "Fail to get permutation degree 1@i={}", i); } assert_eq!(get_permutation_for(&words, 0, 0).unwrap().len(), 0, "Fail to get permutation degree 0"); } #[test] fn test_heap_permutation_6() { let mut data = [1, 2, 3, 4, 5, 6]; let mut counter = 0; heap_permutation(&mut data, |_| { counter +=1; }); assert_eq!(720, counter); } #[test] fn test_heap_permutation_10() { use std::time::{Instant}; let mut data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; let mut counter = 0; let timer = Instant::now(); // println!("{:?}", data); heap_permutation(&mut data, |_| { // println!("{:?}", perm); counter += 1; }); println!("Total {} permutations done in {:?}", counter, timer.elapsed()); assert_eq!(3628800, counter); } #[allow(non_snake_case, unused)] #[test] fn test_CartesianProduct() { use std::time::Instant; let data : &[&[usize]] = &[&[1, 2, 3], &[4, 5, 6], &[7, 8, 9]]; let cart = CartesianProductIterator::new(&data); let mut counter = 0; let timer = Instant::now(); for p in cart { // println!("{:?}", p); counter += 1; } assert_eq!(data.iter().fold(1, |cum, domain| {cum * domain.len()}), counter); println!("Total {} products done in {:?}", counter, timer.elapsed()); } #[allow(non_snake_case, unused)] #[test] fn test_SelfCartesianProduct() { use std::time::Instant; let data : &[usize] = &[1, 2, 3]; let n = 3; let cart = SelfCartesianProductIterator::new(&data, n); let mut counter = 0; let timer = Instant::now(); for p in cart { println!("{:?}", p); counter += 1; } assert_eq!(data.len().pow(n as u32), counter); println!("Total {} products done in {:?}", counter, timer.elapsed()); } #[allow(non_snake_case, unused)] #[test] fn test_CartesianProduct_reset() { use std::time::Instant; let data : &[&[usize]] = &[&[1, 2, 3], &[4, 5, 6], &[7, 8, 9]]; let mut counter = 0; let mut result : Vec<&usize> = vec![&data[0][0]; data.len()]; unsafe { let mut cart = CartesianProductRefIter::new(&data, result.as_mut_slice()); let timer = Instant::now(); while let Some(_) = cart.next() { counter += 1; } let all_possible = data.iter().fold(1, |cum, domain| {cum * domain.len()}); assert_eq!(all_possible, counter); counter = 0; // it shall end immediately because it's already exhausted while let Some(_) = cart.next() { counter += 1; } assert_eq!(0, counter); cart.reset(); counter = 0; // now it shall start iterating again. for _ in cart { counter += 1; } assert_eq!(all_possible, counter); println!("Total {} products done in {:?}", counter, timer.elapsed()); } } #[allow(non_snake_case, unused)] #[test] fn test_CartesianProduct_mimic_iterator() { use std::time::Instant; let data : &[&[usize]] = &[&[1, 2], &[3, 4, 5, 6], &[7, 8, 9], &[10, 11, 12,]]; let mut result : Vec<&usize> = vec![&data[0][0]; data.len()]; unsafe { let mut cart = CartesianProductRefIter::new(&data, result.as_mut_slice()); let mut counter = 0; let timer = Instant::now(); for _ in cart { // println!("{:?}", p); counter += 1; } assert_eq!(data.iter().fold(1, |cum, domain| {cum * domain.len()}), counter); println!("Total {} products done in {:?}", counter, timer.elapsed()); } } #[allow(non_snake_case, unused)] #[test] fn test_SelfCartesianProduct_cell() { use std::time::Instant; let data : &[usize] = &[1, 2, 3]; let n = 3; let mut result = vec![&data[0]; n]; let shared = Rc::new(RefCell::new(result.as_mut_slice())); let cart = SelfCartesianProductCellIter::new(&data, n, Rc::clone(&shared)); let mut counter = 0; let timer = Instant::now(); for _ in cart { println!("{:?}", &*shared.borrow()); counter += 1; } assert_eq!(data.len().pow(n as u32), counter); println!("Total {} products done in {:?}", counter, timer.elapsed()); } #[allow(non_snake_case, unused)] #[test] fn test_SelfCartesianProduct_ref() { use std::time::Instant; let data : &[usize] = &[1, 2, 3]; let n = 3; let result : &mut[&usize] = &mut vec![&data[0]; n]; let shared = result as *mut[&usize]; unsafe { let cart = SelfCartesianProductRefIter::new(&data, n, result); let mut counter = 0; let timer = Instant::now(); for _ in cart { println!("{:?}", &*shared); counter += 1; } assert_eq!(data.len().pow(n as u32), counter); println!("Total {} products done in {:?}", counter, timer.elapsed()); } } #[allow(non_snake_case, unused)] #[test] fn test_CartesianProduct_mimic_iterator_2() { use std::time::Instant; let data : &[&[usize]] = &[&[1, 2], &[3, 4, 5, 6], &[7, 8, 9], &[10, 11, 12,]]; let mut result : Vec<&usize> = vec![&data[0][0]; data.len()]; unsafe { let mut cart = CartesianProductRefIter::new(&data, result.as_mut_slice() as *mut [&usize]); let mut counter = 0; let timer = Instant::now(); for _ in cart { // println!("{:?}", p); counter += 1; } assert_eq!(data.iter().fold(1, |cum, domain| {cum * domain.len()}), counter); println!("Total {} products done in {:?}", counter, timer.elapsed()); } } #[allow(non_snake_case, unused)] #[test] fn test_CartesianProduct_trait() { use std::time::Instant; let mut counter = 0; let timer = Instant::now(); let data : &[&[u8]]= &[&[1, 2, 3], &[4, 5, 6], &[7, 8, 9]]; data.cart_prod().for_each(|p| { counter += 1; }); assert_eq!(data.iter().fold(1, |cum, domain| {cum * domain.len()}), counter); println!("Total {} products done in {:?}", counter, timer.elapsed()); } #[allow(non_snake_case, unused)] #[test] fn test_CartesianProduct_shared_trait() { use std::time::Instant; let mut counter = 0; let timer = Instant::now(); let data : &[&[u8]]= &[&[1, 2], &[3, 4, 5, 6], &[7, 8, 9], &[10, 11, 12,]]; let mut result = vec![&data[0][0]; data.len()]; let shared = Rc::new(RefCell::new(result.as_mut_slice())); (data, Rc::clone(&shared)).cart_prod().for_each(|_| { counter += 1; }); assert_eq!(data.iter().fold(1, |cum, domain| {cum * domain.len()}), counter); println!("Total {} products done in {:?}", counter, timer.elapsed()); } #[allow(non_snake_case, unused)] #[test] fn test_CartesianProduct_ptr_trait() { use std::time::Instant; let mut counter = 0; let timer = Instant::now(); let data : &[&[u8]]= &[&[1, 2], &[3, 4, 5, 6], &[7, 8, 9], &[10, 11, 12,]]; let mut result = vec![&data[0][0]; data.len()]; let shared = result.as_mut_slice() as *mut [&u8]; (data, shared).cart_prod().for_each(|_| { counter += 1; }); assert_eq!(data.iter().fold(1, |cum, domain| {cum * domain.len()}), counter); println!("Total {} products done in {:?}", counter, timer.elapsed()); } #[allow(unused)] #[test] fn test_k_permutation_fn() { use std::time::{Instant}; let data = [1, 2, 3, 4, 5]; let k = 3; let mut counter = 0; let timer = Instant::now(); k_permutation(&data, k, |permuted| { // uncomment line below to print all k-permutation println!("{}:{:?}", counter, permuted); counter += 1; }); println!("Total {} permutations done in {:?}", counter, timer.elapsed()); assert_eq!(divide_factorial(data.len(), data.len() - k), counter); } #[allow(unused)] #[should_panic] #[test] fn test_k_permutation_empty_dom() { use std::time::{Instant}; let data : &[i32] = &[]; let k = 1; let mut counter = 0; let timer = Instant::now(); k_permutation(&data, k, |permuted| { // uncomment line below to print all k-permutation println!("{}:{:?}", counter, permuted); counter += 1; }); println!("Total {} permutations done in {:?}", counter, timer.elapsed()); assert_eq!(divide_factorial(data.len(), data.len() - k), counter); } #[allow(unused)] #[test] fn test_k_permutation_k_1() { use std::time::{Instant}; let data : &[i32] = &[1, 2]; let k = 1; let mut counter = 0; let timer = Instant::now(); k_permutation(&data, k, |permuted| { // uncomment line below to print all k-permutation println!("{}:{:?}", counter, permuted); counter += 1; }); println!("Total {} permutations done in {:?}", counter, timer.elapsed()); assert_eq!(divide_factorial(data.len(), data.len() - k), counter); } #[allow(unused)] #[test] #[ignore] fn test_large_k_permutation() { use std::time::{Instant}; let data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13]; let k = 11; let mut counter = 0; let timer = Instant::now(); k_permutation(&data, k, |permuted| { // uncomment line below to print all k-permutation // println!("{}:{:?}", counter, permuted); counter += 1; }); println!("Total {} permutations done in {:?}", counter, timer.elapsed()); assert_eq!(divide_factorial(data.len(), data.len() - k), counter); } // #[test] // fn test_gosper_combination() { // let mut comb = 7; // for _ in 0..40 { // gosper_combination(&mut comb); // println!("next_combination is {:b}", comb); // } // } #[allow(non_snake_case, unused)] #[test] fn test_HeapPermutation() { use std::time::{Instant}; let mut data : Vec<String> = (1..=3).map(|num| {format!("some ridiculously long word prefix without any point{}", num)}).collect(); // let data = &mut [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; // println!("0:{:?}", data); let mut permutator = HeapPermutationIterator::new(&mut data); let timer = Instant::now(); let mut counter = 1; while let Some(permutated) = permutator.next() { // println!("{}:{:?}", counter, permutated); counter += 1; } assert_eq!(6, counter); println!("Done {} permutations in {:?}", counter, timer.elapsed()); } #[allow(non_snake_case, unused)] #[test] fn test_XPermutationIterator() { use std::time::{Instant}; let mut data : Vec<u32> = (0..3).map(|num| num).collect(); let mut permutator = XPermutationIterator::new(&data, |_| true); let timer = Instant::now(); let mut counter = 0; while let Some(permutated) = permutator.next() { // println!("{}:{:?}", counter, permutated); counter += 1; } assert_eq!(factorial(data.len()), counter); println!("Done {} permutations in {:?}", counter, timer.elapsed()); } #[allow(non_snake_case, unused)] #[test] fn test_XPermutationCellIter() { use std::time::{Instant}; let mut data : Vec<u32> = (0..3).map(|num| num).collect(); let mut result = vec![&data[0]; data.len()]; let share = Rc::new(RefCell::new(result.as_mut_slice())); let mut permutator = XPermutationCellIter::new(&data, Rc::clone(&share), |_| true); let timer = Instant::now(); let mut counter = 0; while let Some(_) = permutator.next() { println!("{}:{:?}", counter, &*share.borrow()); counter += 1; } assert_eq!(factorial(data.len()), counter); println!("Done {} permutations in {:?}", counter, timer.elapsed()); } #[allow(non_snake_case, unused)] #[test] fn test_XPermutationRefIter() { use std::time::{Instant}; let mut data : Vec<u32> = (0..3).map(|num| num).collect(); let mut result = vec![&data[0]; data.len()]; let share = result.as_mut_slice() as *mut [&u32]; unsafe { let mut permutator = XPermutationRefIter::new(&data, share, |_| true); let timer = Instant::now(); let mut counter = 0; while let Some(_) = permutator.next() { println!("{}:{:?}", counter, result); counter += 1; } assert_eq!(factorial(data.len()), counter); println!("Done {} permutations in {:?}", counter, timer.elapsed()); } } #[allow(non_snake_case, unused)] #[ignore] #[test] fn test_XPermutationIterator_mt() { use std::time::{Instant}; let data : Vec<usize> = (0..3).map(|num| num).collect(); let threads = 3; let chunk = data.len() / threads; let (tx, rx) = mpsc::channel(); for i in 0..threads { let start = chunk * i; let end = match i { j if j == threads - 1 => data.len(), // last thread handle remaining work _ => chunk * (i + 1) }; let l_dat = data.to_owned(); // copy data for each thread let end_sig = tx.clone(); thread::spawn(move || { let timer = Instant::now(); let perm = XPermutationIterator::new( &l_dat, |v| *v[0] >= start && *v[0] < end // skip branch that is outside the start/end ); let mut counter = 0u64; for p in perm { // each permutation is stored in p counter += 1; } end_sig.send(i).unwrap(); }); } let main = thread::spawn(move || { // main thread let mut counter = 0; while counter < threads { let i = rx.recv().unwrap(); // do something counter += 1; } }); main.join().unwrap(); } #[allow(non_snake_case, unused)] #[test] fn test_HeapPermutation_reset() { use std::time::{Instant}; let mut data : Vec<String> = (1..=3).map(|num| {format!("some ridiculously long word prefix without any point{}", num)}).collect(); // let data = &mut [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; println!("0:{:?}", data); let mut permutator = HeapPermutationIterator::new(&mut data); let timer = Instant::now(); let mut counter = 1; while let Some(permutated) = permutator.next() { // println!("{}:{:?}", counter, permutated); counter += 1; } assert_eq!(6, counter); let mut counter = 1; while let Some(permutated) = permutator.next() { // println!("{}:{:?}", counter, permutated); counter += 1; } assert_eq!(1, counter); permutator.reset(); let mut counter = 1; while let Some(permutated) = permutator.next() { // println!("{}:{:?}", counter, permutated); counter += 1; } assert_eq!(6, counter); } #[allow(non_snake_case, unused)] #[test] fn test_HeapPermutationIntoIterator() { use std::time::{Instant}; let mut data : Vec<String> = (1..=3).map(|num| {format!("some ridiculously long word prefix without any point{}", num)}).collect(); // let data = &mut [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; println!("0:{:?}", data); let permutator = HeapPermutationIterator::new(&mut data); let timer = Instant::now(); let mut counter = 1; permutator.into_iter().for_each(|permutated| {counter += 1;}); println!("Done {} permutations in {:?}", counter, timer.elapsed()); assert_eq!(6, counter); } #[allow(non_snake_case, unused)] #[test] fn test_HeapPermutationRefIterator() { use std::time::{Instant}; let mut data : Vec<String> = (1..=3).map(|num| {format!("some ridiculously long word prefix without any point{}", num)}).collect(); // let data = &mut [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; // println!("0:{:?}", data); unsafe { let mut permutator = HeapPermutationRefIter::new(data.as_mut_slice()); let timer = Instant::now(); let mut counter = 1; while let Some(permutated) = permutator.next() { // println!("{}:{:?}", counter, permutated); counter += 1; } assert_eq!(6, counter); println!("Done perm_ref {} permutations in {:?}", counter, timer.elapsed()); } } #[allow(non_snake_case, unused)] #[test] fn test_HeapPermutationCellIterIterator() { use std::time::{Instant}; let mut data : Vec<String> = (1..=3).map(|num| {format!("some ridiculously long word prefix without any point{}", num)}).collect(); let shared = Rc::new(RefCell::new(data.as_mut_slice())); // let data = &mut [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; let permutator = HeapPermutationCellIter::new(Rc::clone(&shared)); println!("{}:{:?}", 0, &*shared.borrow()); let timer = Instant::now(); let mut counter = 1; for _ in permutator { println!("{}:{:?}", counter, &*shared.borrow()); counter += 1; } println!("Done {} permutations in {:?}", counter, timer.elapsed()); assert_eq!(6, counter); } #[allow(non_snake_case, unused)] #[test] fn test_GosperCombinationIterator() { use std::time::{Instant}; let gosper = GosperCombinationIterator::new(&[1, 2, 3, 4, 5], 3); let mut counter = 0; let timer = Instant::now(); for combination in gosper { // println!("{}:{:?}", counter, combination); counter += 1; } println!("Total {} combinations in {:?}", counter, timer.elapsed()); assert_eq!(10, counter); } #[allow(non_snake_case, unused)] #[test] fn test_LargeCombinationIterator() { use std::time::{Instant}; let data : &[i32] = &[1, 2, 3, 4, 5]; let k = 3; let mut combs = LargeCombinationIterator::new(data, k); let mut counter = 0; let timer = Instant::now(); for combination in combs.iter() { println!("{}:{:?}", counter, combination); counter += 1; } println!("Total {} combinations in {:?}", counter, timer.elapsed()); assert_eq!(divide_factorial(data.len(), data.len() - k) / factorial(k), counter); // test continue on exhausted iterator for combination in combs.iter() { println!("{}:{:?}", counter, combination); counter += 1; } assert_eq!(divide_factorial(data.len(), data.len() - k) / factorial(k), counter); // test reset the iterator combs.reset(); let mut counter = 0; let timer = Instant::now(); for combination in combs.iter() { println!("{}:{:?}", counter, combination); counter += 1; } println!("Total {} combinations in {:?}", counter, timer.elapsed()); assert_eq!(divide_factorial(data.len(), data.len() - k) / factorial(k), counter); } #[allow(non_snake_case, unused)] #[test] fn test_LargeCombinationIterator_single() { use std::time::{Instant}; let data : &[i32] = &[1, 2, 3, 4, 5]; let k = 1; let mut combs = LargeCombinationIterator::new(data, k); let mut counter = 0; let timer = Instant::now(); for combination in combs.iter() { println!("{}:{:?}", counter, combination); counter += 1; } println!("Total {} combinations in {:?}", counter, timer.elapsed()); assert_eq!(divide_factorial(data.len(), data.len() - k) / factorial(k), counter); // test continue on exhausted iterator for combination in combs.iter() { println!("{}:{:?}", counter, combination); counter += 1; } assert_eq!(divide_factorial(data.len(), data.len() - k) / factorial(k), counter); // test reset the iterator combs.reset(); let mut counter = 0; let timer = Instant::now(); for combination in combs.iter() { println!("{}:{:?}", counter, combination); counter += 1; } println!("Total {} combinations in {:?}", counter, timer.elapsed()); assert_eq!(divide_factorial(data.len(), data.len() - k) / factorial(k), counter); } #[allow(non_snake_case, unused)] #[test] fn test_GosperCombinationIteratorUnsafe() { use std::time::{Instant}; let data = &[1, 2, 3, 4, 5, 6]; let r = 4; let mut counter = 0; let timer = Instant::now(); let mut result = vec![&data[0]; r]; unsafe { let mut gosper = GosperCombinationRefIter::new(data, r, result.as_mut_slice() as *mut [&i32]); for _ in gosper { // println!("{}:{:?}", counter, combination); counter += 1; } println!("Total {} combinations in {:?}", counter, timer.elapsed()); assert_eq!(counter, divide_factorial(data.len(), data.len() - r) / factorial(r)); } } #[allow(non_snake_case, unused)] #[test] fn test_GosperCombinationCellIter() { use std::time::{Instant}; let data = &[1, 2, 3, 4, 5, 6]; let r = 3; let mut counter = 0; let timer = Instant::now(); let mut result = vec![&data[0]; r]; let shared = Rc::new(RefCell::new(result.as_mut_slice())); let mut gosper = GosperCombinationCellIter::new(data, r, Rc::clone(&shared)); for _ in gosper { // println!("{}:{:?}", counter, &*shared.borrow()); counter += 1; } println!("Total {} combinations in {:?}", counter, timer.elapsed()); assert_eq!(counter, divide_factorial(data.len(), data.len() - r) / factorial(r)); } #[allow(non_snake_case, unused)] #[test] fn test_GosperCombinationIteratorAlike_reset() { use std::time::{Instant}; let data = &[1, 2, 3, 4, 5]; let r = 3; let mut counter = 0; let timer = Instant::now(); let mut result = vec![&data[0]; r]; unsafe { let mut gosper = GosperCombinationRefIter::new(data, r, result.as_mut_slice() as *mut [&i32]); let mut iter = gosper.into_iter(); while let Some(_) = iter.next() { println!("{}:{:?}", counter, result); counter += 1; } println!("Total {} combinations in {:?}", counter, timer.elapsed()); let all_possible = divide_factorial(data.len(), r) / factorial(data.len() - r); assert_eq!(all_possible, counter); counter = 0; while let Some(_) = iter.next() { // println!("{}:{:?}", counter, combination); counter += 1; } assert_eq!(0, counter); iter.reset(); counter = 0; while let Some(_) = iter.next() { // println!("{}:{:?}", counter, combination); counter += 1; } assert_eq!(all_possible, counter); } } #[allow(non_snake_case, unused)] #[test] fn test_KPermutationIterator() { use std::time::Instant; let data = [1, 2, 3, 4, 5]; let k = 3; let permutator = KPermutationIterator::new(&data, k); let mut counter = 0; // println!("Begin testing KPermutation"); let timer = Instant::now(); for permuted in permutator { println!("{}:{:?}", counter, permuted); counter += 1; } println!("Total {} permutations done in {:?}", counter, timer.elapsed()); assert_eq!(divide_factorial(data.len(), data.len() - k), counter); } #[allow(non_snake_case, unused)] #[test] fn test_KPermutationIteratorBound() { use std::time::Instant; let data = [1, 2, 3, 4]; let k = 4; let permutator = KPermutationIterator::new(&data, k); let mut counter = 0; // println!("Begin testing KPermutation"); let timer = Instant::now(); for permuted in permutator { println!("{}:{:?}", counter, permuted); counter += 1; } println!("Total {} permutations done in {:?}", counter, timer.elapsed()); assert_eq!(divide_factorial(data.len(), data.len() - k), counter); } #[allow(non_snake_case)] #[test] fn test_KPermutation_into_Cell() { use std::time::Instant; let data : &[i32] = &[1, 2, 3, 4, 5]; let mut counter = 0; let k = 3; let mut result : Vec<&i32> = vec![&data[0]; k]; let shared = Rc::new(RefCell::new(result.as_mut_slice())); let timer = Instant::now(); KPermutationCellIter::new(data, k, Rc::clone(&shared)).into_iter().for_each(|_| { // println!("{:?}", &*shared); counter += 1; }); println!("Total {} combination done in {:?}", counter, timer.elapsed()); assert_eq!(counter, divide_factorial(data.len(), data.len() - k)); } #[allow(non_snake_case)] #[test] fn test_KPermutation_into_Ref() { use std::time::Instant; let data : &[i32] = &[1, 2, 3, 4, 5]; let mut counter = 0; let k = 3; let mut result : Vec<&i32> = vec![&data[0]; k]; let shared = result.as_mut_slice() as *mut [&i32]; let timer = Instant::now(); unsafe { KPermutationRefIter::new(data, k, shared).into_iter().for_each(|_| { // println!("{:?}", &*shared); counter += 1; }); println!("Total {} combination done in {:?}", counter, timer.elapsed()); assert_eq!(counter, divide_factorial(data.len(), data.len() - k)); } } #[allow(unused)] #[test] fn test_cartesian_product() { use std::time::Instant; let set = (1..4).map(|item| item).collect::<Vec<u64>>(); let mut data = Vec::<&[u64]>::new(); for _ in 0..4 { data.push(&set); } let mut counter = 0; let timer = Instant::now(); cartesian_product(&data, |product| { // println!("{:?}", product); counter += 1; }); println!("Total {} product done in {:?}", counter, timer.elapsed()); } #[allow(unused)] #[test] fn test_self_cartesian_product() { use std::time::Instant; let data : &[i32] = &[1, 2, 3]; let n = 3; let mut counter = 0; let timer = Instant::now(); self_cartesian_product(&data, 3, |product| { println!("{:?}", product); counter += 1; }); println!("Total {} product done in {:?}", counter, timer.elapsed()); } #[allow(unused)] #[should_panic] #[test] fn test_self_cartesian_product_zero() { use std::time::Instant; let data : &[i32] = &[1, 2, 3]; let n = 0; let mut counter = 0; let timer = Instant::now(); self_cartesian_product(&data, n, |product| { println!("{:?}", product); counter += 1; }); println!("Total {} product done in {:?}", counter, timer.elapsed()); } #[test] fn test_combination_trait() { let data = [1, 2, 3, 4, 5, 6, 7, 8]; let k = 4; let mut counter = 0; for combination in data.combination(k) { println!("{:?}", combination); counter += 1; } assert_eq!(counter, divide_factorial(data.len(), data.len() - k) / factorial(k) ); // n!/(k!(n-k!)) } #[test] fn test_combination_trait_share() { let data : &[i32] = &[1, 2, 3, 4, 5, 6, 7, 8]; let k = 3; let mut result = vec![&data[0]; k]; let shared = Rc::new(RefCell::new(result.as_mut_slice())); let combination_op = (data, shared); let mut counter = 0; for combination in combination_op.combination(k) { println!("{:?}", combination); counter += 1; } assert_eq!(counter, divide_factorial(data.len(), data.len() - k) / factorial(k) ); // n!/(k!(n-k!)) } #[test] fn test_combination_trait_ptr() { let data : &[i32] = &[1, 2, 3, 4, 5, 6]; let k = 4; let mut result = vec![&data[0]; k]; let shared = result.as_mut_slice() as *mut [&i32]; let combination_op = (data, shared); let mut counter = 0; unsafe { for _ in combination_op.combination(k) { println!("{:?}", &*shared); counter += 1; } } assert_eq!(counter, divide_factorial(data.len(), data.len() - k) / factorial(k) ); // n!/(k!(n-k!)) } #[test] fn test_large_combination_fn_k_1() { let data : &[i32] = &[1, 2, 3, 4, 5, 6]; let k = 1; let mut counter = 0; large_combination(data, k, |_result| { counter += 1; }); assert_eq!(counter, divide_factorial(data.len(), data.len() - k) / factorial(k) ); // n!/(k!(n-k!)) } #[should_panic] #[test] fn test_large_combination_fn_k_0() { let data : &[i32] = &[1, 2, 3, 4, 5, 6]; let k = 0; let mut counter = 0; large_combination(data, k, |_result| { counter += 1; }); assert_eq!(counter, divide_factorial(data.len(), data.len() - k) / factorial(k) ); // n!/(k!(n-k!)) } #[test] fn test_large_combination_fn_d_eq_k() { let data : &[i32] = &[1, 2, 3]; let k = 3; let mut counter = 0; large_combination(data, k, |_result| { // println!("{:?}", _result); counter += 1; }); assert_eq!(counter, divide_factorial(data.len(), data.len() - k) / factorial(k) ); // n!/(k!(n-k!)) } #[test] fn test_large_combination_fn() { let data : &[i32] = &[1, 2, 3, 4, 5]; let k = 3; let mut counter = 0; large_combination(data, k, |_result| { // println!("{:?}", _result); counter += 1; }); assert_eq!(counter, divide_factorial(data.len(), data.len() - k) / factorial(k) ); // n!/(k!(n-k!)) } #[test] fn test_permutation_trait() { let mut data = [1, 2, 3]; // println!("{:?}", data); let mut counter = 0; for permuted in data.permutation() { println!("test_permutation_trait: {:?}", permuted); counter += 1; } assert_eq!(counter, factorial(data.len())); } #[test] fn test_permutation_trait_cell() { let data : &mut[i32] = &mut [1, 2, 3, 4, 5]; let mut shared = Rc::new(RefCell::new(data)); let value = Rc::clone(&shared); let mut counter = 0; shared.permutation().for_each(|_| { println!("test_permutation_trait_cell: {:?}", &*value.borrow()); counter += 1; }); assert_eq!(counter, factorial(value.borrow().len())); } #[test] fn test_permutation_trait_ref() { let data : &mut[i32] = &mut [1, 2, 3, 4, 5]; let mut shared = data as *mut [i32]; let mut counter = 0; shared.permutation().for_each(|_| { println!("test_permutation_trait_ref: {:?}", data); counter += 1; }); assert_eq!(counter, factorial(data.len())); } #[test] fn test_k_permutation_primitive() { let data = [1, 2, 3, 4, 5]; let k = 3; let mut counter = 0; data.combination(k).for_each(|mut combination| { combination.permutation().for_each(|permuted| { println!("test_k_permutation_primitive: {:?}", permuted); counter += 1; }); }); assert_eq!(counter, divide_factorial(data.len(), data.len() - k)); } #[allow(non_snake_case)] #[test] fn test_KPermutation_trait() { let data : &mut[i32] = &mut [1, 2, 3, 4, 5]; let mut counter = 0; (&*data, 3usize).permutation().for_each(|_p| { // println!("{:?}", p); counter += 1; }); assert_eq!(counter, divide_factorial(data.len(), data.len() - 3)); } #[allow(non_snake_case)] #[test] fn test_KPermutation_single() { let data : &mut[i32] = &mut [1, 2, 3, 4, 5]; let mut counter = 0; let k = 1usize; (&*data, k).permutation().for_each(|_p| { println!("{:?}", _p); counter += 1; }); assert_eq!(counter, divide_factorial(data.len(), data.len() - k)); } #[allow(non_snake_case)] #[test] fn test_KPermutation_into_cell_trait() { use std::time::Instant; let data : &mut[i32] = &mut [1, 2, 3, 4, 5, 6]; let mut counter = 0; let k = 2; let mut result : Vec<&i32> = vec![&data[0]; k]; let shared = Rc::new(RefCell::new(result.as_mut_slice())); let timer = Instant::now(); (&*data, k, Rc::clone(&shared)).permutation().for_each(|_| { // println!("{:?}", &*shared.borrow()); counter += 1; }); println!("Total {} combination done in {:?}", counter, timer.elapsed()); assert_eq!(counter, divide_factorial(data.len(), data.len() - k)); } #[allow(non_snake_case, unused_unsafe)] #[test] fn test_KPermutation_into_Ref_trait() { use std::time::Instant; let data : &[i32] = &[1, 2, 3, 4, 5]; let mut counter = 0; let k = 3; let mut result : Vec<&i32> = vec![&data[0]; k]; let shared = result.as_mut_slice() as *mut [&i32]; let timer = Instant::now(); unsafe { (data, k, shared).permutation().for_each(|_| { // println!("{:?}", &*shared); counter += 1; }); println!("Total {} combination done in {:?}", counter, timer.elapsed()); assert_eq!(counter, divide_factorial(data.len(), data.len() - k)); } } // #[test] // fn test_lexicographic_combination() { // let mut x = 7; // for _ in 0..40 { // println!("{:0>8b}", x); // stanford_combination(&mut x); // } // } #[test] fn test_combination_fn() { let data = [1, 2, 3, 4, 5]; let r = 3; let mut counter = 0; combination(&data, r, |comb| { println!("{:?}", comb); counter += 1; }); assert_eq!(counter, divide_factorial(data.len(), data.len() - r) / factorial(r)); } #[test] fn test_combination_fn_single() { let data = [1]; let r = 1; let mut counter = 0; combination(&data, r, |comb| { println!("{:?}", comb); counter += 1; }); assert_eq!(counter, divide_factorial(data.len(), data.len() - r) / factorial(r)); } #[test] fn test_combination_fn_bound() { let data = [1, 2, 3]; let r = 3; let mut counter = 0; combination(&data, r, |comb| { println!("{:?}", comb); counter += 1; }); assert_eq!(counter, divide_factorial(data.len(), data.len() - r) / factorial(r)); } #[test] fn test_large_combination_cell_fn() { let data : &mut [i32] = &mut [1, 2, 3, 4, 5]; let r = 3; let mut counter = 0; let mut result : Vec<&i32> = vec![&data[0]; r]; let shared : Rc<RefCell<&mut [&i32]>> = Rc::new(RefCell::new(&mut result)); large_combination_cell(&data, r, Rc::clone(&shared), || { println!("{:?}", shared.borrow()); counter += 1; }); assert_eq!(counter, divide_factorial(data.len(), data.len() - r) / factorial(r)); } #[test] fn test_large_combination_sync_fn() { let data : &mut [i32] = &mut [1, 2, 3, 4, 5]; let r = 3; let mut counter = 0; let result : Vec<&i32> = vec![&data[0]; r]; let shared : Arc<RwLock<Vec<&i32>>> = Arc::new(RwLock::new(result)); large_combination_sync(&data, r, Arc::clone(&shared), || { println!("{:?}", shared.read().unwrap()); counter += 1; }); assert_eq!(counter, divide_factorial(data.len(), data.len() - r) / factorial(r)); } #[test] fn test_unsafe_combination_fn() { let data = [1, 2, 3, 4, 5]; let r = 3; let mut counter = 0; let mut result = vec![&data[0]; r]; let result_ptr = result.as_mut_slice() as *mut [&usize]; unsafe { unsafe_combination(&data, r, result_ptr, || { println!("{:?}", result); counter += 1; }); } assert_eq!(counter, divide_factorial(data.len(), data.len() - r) / factorial(r)); } #[test] fn test_combination_cell_fn() { let data = [1, 2, 3, 4, 5]; let r = 3; let mut counter = 0; let mut result = vec![&data[0]; r]; let result_cell = Rc::new(RefCell::new(result.as_mut_slice())); combination_cell(&data, r, Rc::clone(&result_cell), || { println!("{:?}", result_cell.borrow()); counter += 1; }); assert_eq!(counter, divide_factorial(data.len(), data.len() - r) / factorial(r)); } #[test] fn test_unsafe_shared_combination_result_fn() { use std::fmt::Debug; trait Consumer { fn consume(&self); } struct Worker1<'a, T : 'a> { data : &'a[&'a T] } impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { fn consume(&self) { // println!("Work1 has {:?}", self.data); self.data.iter().for_each(|_| {}); } } struct Worker2<'a, T : 'a> { data : &'a[&'a T] } impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { fn consume(&self) { // println!("Work2 has {:?}", self.data); self.data.iter().for_each(|_| {}); } } unsafe fn start_combination_process<'a>(data : &'a[i32], cur_result : *mut [&'a i32], k : usize, consumers : Vec<Box<dyn Consumer + 'a>>) { use std::time::Instant; let timer = Instant::now(); let mut counter = 0; unsafe_combination(data, k, cur_result, || { consumers.iter().for_each(|c| { c.consume(); }); counter += 1; }); println!("Done {} combinations with 2 workers in {:?}", counter, timer.elapsed()); } let k = 5; let data = &[1, 2, 3, 4, 5, 6]; let mut result = vec![&data[0]; k]; unsafe { let shared = result.as_mut_slice() as *mut [&i32]; let worker1 = Worker1 { data : &result }; let worker2 = Worker2 { data : &result }; let consumers : Vec<Box<dyn Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; start_combination_process(data, shared, k, consumers); } } #[test] fn test_shared_combination_result_fn() { use std::fmt::Debug; trait Consumer { fn consume(&self); } struct Worker1<'a, T : 'a> { data : Rc<RefCell<&'a mut[&'a T]>> } impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { fn consume(&self) { // println!("Work1 has {:?}", self.data.borrow()); let result = self.data.borrow(); result.iter().for_each(|_| {}); } } struct Worker2<'a, T : 'a> { data : Rc<RefCell<&'a mut[&'a T]>> } impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { fn consume(&self) { // println!("Work2 has {:?}", self.data.borrow()); let result = self.data.borrow(); result.iter().for_each(|_| {}); } } fn start_combination_process<'a>(data : &'a[i32], cur_result : Rc<RefCell<&'a mut[&'a i32]>>, k : usize, consumers : Vec<Box<dyn Consumer + 'a>>) { use std::time::Instant; let timer = Instant::now(); let mut counter = 0; combination_cell(data, k, cur_result, || { consumers.iter().for_each(|c| { c.consume(); }); counter += 1; }); println!("Done {} combinations with 2 workers in {:?}", counter, timer.elapsed()); } let k = 4; let data = &[1, 2, 3, 4, 5, 6, 7]; let mut result = vec![&data[0]; k]; let result_cell = Rc::new(RefCell::new(result.as_mut_slice())); let worker1 = Worker1 { data : Rc::clone(&result_cell) }; let worker2 = Worker2 { data : Rc::clone(&result_cell) }; let consumers : Vec<Box<dyn Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; start_combination_process(data, result_cell, k, consumers); } #[test] fn test_shared_combination_result_sync_fn() { fn start_combination_process<'a>(data : &'a[i32], cur_result : Arc<RwLock<Vec<&'a i32>>>, k : usize, notifier : Vec<SyncSender<Option<()>>>, release_recv : Receiver<()>) { use std::time::Instant; let timer = Instant::now(); let mut counter = 0; combination_sync(data, k, cur_result, || { notifier.iter().for_each(|n| { n.send(Some(())).unwrap(); // notify every thread that new data available }); for _ in 0..notifier.len() { release_recv.recv().unwrap(); // block until all thread reading data notify on read completion } counter += 1; }); notifier.iter().for_each(|n| {n.send(None).unwrap()}); // notify every thread that there'll be no more data. println!("Done {} combinations with 2 workers in {:?}", counter, timer.elapsed()); } let k = 4; let data = &[1, 2, 3, 4, 5, 6]; let result = vec![&data[0]; k]; let result_sync = Arc::new(RwLock::new(result)); // workter thread 1 let (t1_send, t1_recv) = mpsc::sync_channel::<Option<()>>(0); let (main_send, main_recv) = mpsc::sync_channel(0); let t1_local = main_send.clone(); let t1_dat = Arc::clone(&result_sync); thread::spawn(move || { while let Some(_) = t1_recv.recv().unwrap() { let _result : &Vec<&i32> = &*t1_dat.read().unwrap(); // println!("Thread1: {:?}", _result); t1_local.send(()).unwrap(); // notify generator thread that reference is no longer neeed. } println!("Thread1 is done"); }); // worker thread 2 let (t2_send, t2_recv) = mpsc::sync_channel::<Option<()>>(0); let t2_dat = Arc::clone(&result_sync); let t2_local = main_send.clone(); thread::spawn(move || { while let Some(_) = t2_recv.recv().unwrap() { let _result : &Vec<&i32> = &*t2_dat.read().unwrap(); // println!("Thread2: {:?}", _result); t2_local.send(()).unwrap(); // notify generator thread that reference is no longer neeed. } println!("Thread2 is done"); }); // main thread that generate result thread::spawn(move || { start_combination_process(data, result_sync, k, vec![t1_send, t2_send], main_recv); }).join().unwrap(); } #[allow(non_snake_case)] #[test] fn test_share_result_CombinationIterator_with_thread_fn() { let k = 3; let data : &[i32] = &[1, 2, 3, 4, 5]; // workter thread 1 let (t1_send, t1_recv) = mpsc::sync_channel::<Option<Vec<&i32>>>(0); thread::spawn(move || { while let Some(c) = t1_recv.recv().unwrap() { let _result : Vec<&i32> = c; // println!("Thread1: {:?}", _result); } println!("Thread1 is done"); }); // worker thread 2 let (t2_send, t2_recv) = mpsc::sync_channel::<Option<Vec<&i32>>>(0); thread::spawn(move || { while let Some(c) = t2_recv.recv().unwrap() { let _result : Vec<&i32> = c; // println!("Thread2: {:?}", _result); } println!("Thread2 is done"); }); let channels = vec![t1_send, t2_send]; // main thread that generate result thread::spawn(move || { use std::time::Instant; let timer = Instant::now(); let mut counter = 0; data.combination(k).for_each(|c| { channels.iter().for_each(|t| {t.send(Some(c.to_owned())).unwrap();}); counter += 1; }); channels.iter().for_each(|t| {t.send(None).unwrap()}); println!("Done {} combinations in {:?}", counter, timer.elapsed()); }).join().unwrap(); } #[test] fn test_shared_combination_result_iterator_alike() { use std::fmt::Debug; use std::time::Instant; trait Consumer { fn consume(&self); } struct Worker1<'a, T : 'a> { data : Rc<RefCell<&'a mut[&'a T]>> } impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { fn consume(&self) { // println!("Work1 has {:?}", self.data.borrow()); let result = self.data.borrow(); result.iter().for_each(|_| {}); } } struct Worker2<'a, T : 'a> { data : Rc<RefCell<&'a mut[&'a T]>> } impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { fn consume(&self) { // println!("Work2 has {:?}", self.data.borrow()); let result = self.data.borrow(); result.iter().for_each(|_| {}); } } let k = 4; let data = &[1, 2, 3, 4, 5, 6, 7]; let mut result = vec![&data[0]; k]; let result_cell = Rc::new(RefCell::new(result.as_mut_slice())); let worker1 = Worker1 { data : Rc::clone(&result_cell) }; let worker2 = Worker2 { data : Rc::clone(&result_cell) }; let consumers : Vec<Box<dyn Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; let gosper = GosperCombinationCellIter::new(data, k, result_cell); let timer = Instant::now(); let mut counter = 0; for _ in gosper { consumers.iter().for_each(|c| {c.consume()}); counter += 1; } println!("Total {} combinations done in {:?}", counter, timer.elapsed()); } #[test] fn test_unsafe_cartesian_product_shared_result() { use std::fmt::Debug; trait Consumer { fn consume(&self); } struct Worker1<'a, T : 'a> { data : &'a[&'a T] } impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { fn consume(&self) { println!("Work1 has {:?}", self.data); } } struct Worker2<'a, T : 'a> { data : &'a[&'a T] } impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { fn consume(&self) { println!("Work2 has {:?}", self.data); } } unsafe fn start_cartesian_product_process<'a>(data : &'a[&'a[i32]], cur_result : *mut [&'a i32], consumers : Vec<Box<dyn Consumer + 'a>>) { unsafe_cartesian_product(data, cur_result, || { consumers.iter().for_each(|c| { c.consume(); }) }); } let data : &[&[i32]] = &[&[1, 2], &[3, 4, 5], &[6]]; let mut result = vec![&data[0][0]; data.len()]; unsafe { let shared = result.as_mut_slice() as *mut [&i32]; let worker1 = Worker1 { data : &result }; let worker2 = Worker2 { data : &result }; let consumers : Vec<Box<dyn Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; start_cartesian_product_process(data, shared, consumers); } } #[allow(unused)] #[test] fn test_unsafe_self_cartesian_product_shared_result() { use std::fmt::Debug; trait Consumer { fn consume(&self); } struct Worker1<'a, T : 'a> { data : &'a[&'a T] } impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { fn consume(&self) { // println!("Work1 has {:?}", self.data); } } struct Worker2<'a, T : 'a> { data : &'a[&'a T] } impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { fn consume(&self) { // println!("Work2 has {:?}", self.data); } } unsafe fn start_cartesian_product_process<'a>(data : &'a[i32], n : usize, cur_result : *mut [&'a i32], consumers : Vec<Box<dyn Consumer + 'a>>) { use std::time::Instant; let timer = Instant::now(); let mut counter = 0; unsafe_self_cartesian_product(data, n, cur_result, || { consumers.iter().for_each(|c| { c.consume(); }); counter += 1; }); println!("start_cartesian_product_process: {} products in {:?}", counter, timer.elapsed()); } let data : &[i32] = &[1, 2, 3]; let n = 3; let mut result = vec![&data[0]; n]; unsafe { let shared = result.as_mut_slice() as *mut [&i32]; let worker1 = Worker1 { data : &result }; let worker2 = Worker2 { data : &result }; let consumers : Vec<Box<dyn Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; start_cartesian_product_process(data, n, shared, consumers); } } #[test] fn test_cartesian_product_shared_result_fn() { use std::fmt::Debug; trait Consumer { fn consume(&self); } struct Worker1<'a, T : 'a> { data : Rc<RefCell<&'a mut[&'a T]>> } impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { fn consume(&self) { println!("Work1 has {:?}", self.data); } } struct Worker2<'a, T : 'a> { data : Rc<RefCell<&'a mut[&'a T]>> } impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { fn consume(&self) { println!("Work2 has {:?}", self.data); } } fn start_cartesian_product_process<'a>(data : &'a[&'a[i32]], cur_result : Rc<RefCell<&'a mut [&'a i32]>>, consumers : Vec<Box<dyn Consumer + 'a>>) { cartesian_product_cell(data, cur_result, || { consumers.iter().for_each(|c| { c.consume(); }) }); } let data : &[&[i32]] = &[&[1, 2], &[3, 4, 5], &[6]]; let mut result = vec![&data[0][0]; data.len()]; let shared = Rc::new(RefCell::new(result.as_mut_slice())); let worker1 = Worker1 { data : Rc::clone(&shared) }; let worker2 = Worker2 { data : Rc::clone(&shared) }; let consumers : Vec<Box<dyn Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; start_cartesian_product_process(data, shared, consumers); } #[allow(unused)] #[test] fn test_self_cartesian_product_shared_result_fn() { use std::fmt::Debug; trait Consumer { fn consume(&self); } struct Worker1<'a, T : 'a> { data : Rc<RefCell<&'a mut[&'a T]>> } impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { fn consume(&self) { println!("Work1 has {:?}", self.data); } } struct Worker2<'a, T : 'a> { data : Rc<RefCell<&'a mut[&'a T]>> } impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { fn consume(&self) { println!("Work2 has {:?}", self.data); } } fn start_cartesian_product_process<'a>(data : &'a[i32], n : usize, cur_result : Rc<RefCell<&'a mut [&'a i32]>>, consumers : Vec<Box<dyn Consumer + 'a>>) { self_cartesian_product_cell(data, n, cur_result, || { consumers.iter().for_each(|c| { c.consume(); }) }); } let data : &[i32] = &[1, 2, 3]; let n = 3; let mut result = vec![&data[0]; n]; let shared = Rc::new(RefCell::new(result.as_mut_slice())); let worker1 = Worker1 { data : Rc::clone(&shared) }; let worker2 = Worker2 { data : Rc::clone(&shared) }; let consumers : Vec<Box<dyn Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; start_cartesian_product_process(data, n, shared, consumers); } #[allow(non_snake_case)] #[test] fn test_CartesianProduct_iterator_alike_shared_result() { use std::fmt::Debug; trait Consumer { fn consume(&self); } struct Worker1<'a, T : 'a> { data : Rc<RefCell<&'a mut[&'a T]>> } impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { fn consume(&self) { println!("Work1 has {:?}", self.data); } } struct Worker2<'a, T : 'a> { data : Rc<RefCell<&'a mut[&'a T]>> } impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { fn consume(&self) { println!("Work2 has {:?}", self.data); } } fn start_cartesian_product_process<'a>(data : &'a[&'a[i32]], cur_result : Rc<RefCell<&'a mut [&'a i32]>>, consumers : Vec<Box<dyn Consumer + 'a>>) { let cart = CartesianProductCellIter::new(data, cur_result); for _ in cart { consumers.iter().for_each(|c| { c.consume(); }) }; } let data : &[&[i32]] = &[&[1, 2], &[3, 4, 5], &[6]]; let mut result = vec![&data[0][0]; data.len()]; let shared = Rc::new(RefCell::new(result.as_mut_slice())); let worker1 = Worker1 { data : Rc::clone(&shared) }; let worker2 = Worker2 { data : Rc::clone(&shared) }; let consumers : Vec<Box<dyn Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; start_cartesian_product_process(data, shared, consumers); } #[test] fn test_shared_cartesian_product_result_sync_fn() { fn start_cartesian_product_process<'a>(data : &'a[&[i32]], cur_result : Arc<RwLock<Vec<&'a i32>>>, notifier : Vec<SyncSender<Option<()>>>, release_recv : Receiver<()>) { use std::time::Instant; let timer = Instant::now(); let mut counter = 0; cartesian_product_sync(data, cur_result, || { notifier.iter().for_each(|n| { n.send(Some(())).unwrap(); // notify every thread that new data available }); for _ in 0..notifier.len() { release_recv.recv().unwrap(); // block until all thread reading data notify on read completion } counter += 1; }); notifier.iter().for_each(|n| {n.send(None).unwrap()}); // notify every thread that there'll be no more data. println!("Done {} combinations with 2 workers in {:?}", counter, timer.elapsed()); } let k = 3; let data : &[&[i32]]= &[&[1, 2, 3], &[4, 5], &[6, 7, 8, 9, 10]]; let result = vec![&data[0][0]; k]; let result_sync = Arc::new(RwLock::new(result)); // workter thread 1 let (t1_send, t1_recv) = mpsc::sync_channel::<Option<()>>(0); let (main_send, main_recv) = mpsc::sync_channel(0); let t1_local = main_send.clone(); let t1_dat = Arc::clone(&result_sync); thread::spawn(move || { while let Some(_) = t1_recv.recv().unwrap() { let _result : &Vec<&i32> = &*t1_dat.read().unwrap(); // println!("Thread1: {:?}", _result); t1_local.send(()).unwrap(); // notify generator thread that reference is no longer neeed. } println!("Thread1 is done"); }); // worker thread 2 let (t2_send, t2_recv) = mpsc::sync_channel::<Option<()>>(0); let t2_dat = Arc::clone(&result_sync); let t2_local = main_send.clone(); thread::spawn(move || { while let Some(_) = t2_recv.recv().unwrap() { let _result : &Vec<&i32> = &*t2_dat.read().unwrap(); // println!("Thread2: {:?}", _result); t2_local.send(()).unwrap(); // notify generator thread that reference is no longer neeed. } println!("Thread2 is done"); }); // main thread that generate result thread::spawn(move || { start_cartesian_product_process(data, result_sync, vec![t1_send, t2_send], main_recv); }).join().unwrap(); } #[allow(non_snake_case)] #[test] fn test_shared_CartesianProduct_result_sync() { let data : &[&[i32]]= &[&[1, 2, 3], &[4, 5], &[6, 7, 8, 9]]; let result = vec![&data[0][0]; data.len()]; let result_sync = Arc::new(RwLock::new(result)); // workter thread 1 let (t1_send, t1_recv) = mpsc::sync_channel::<Option<()>>(0); let t1_dat = Arc::clone(&result_sync); thread::spawn(move || { while let Some(_) = t1_recv.recv().unwrap() { let _result : &Vec<&i32> = &*t1_dat.read().unwrap(); println!("Thread1: {:?}", _result); } println!("Thread1 is done"); }); // worker thread 2 let (t2_send, t2_recv) = mpsc::sync_channel::<Option<()>>(0); let t2_dat = Arc::clone(&result_sync); thread::spawn(move || { while let Some(_) = t2_recv.recv().unwrap() { let _result : &Vec<&i32> = &*t2_dat.read().unwrap(); println!("Thread2: {:?}", _result); } println!("Thread2 is done"); }); let consumers = vec![t1_send, t2_send]; // main thread that generate result thread::spawn(move || { use std::time::Instant; let cart = CartesianProductIterator::new(data); let mut counter = 0; let timer = Instant::now(); cart.into_iter().for_each(|_| { consumers.iter().for_each(|c| { c.send(Some(())).unwrap(); }); counter += 1; }); consumers.iter().for_each(|c| { c.send(None).unwrap(); // Explicitly terminate all workers }); println!("Done {} products in {:?}", counter, timer.elapsed()); }).join().unwrap(); } #[allow(non_snake_case)] #[test] fn test_share_CartesianProductIterator_result_to_thread() { let data : &[&[i32]]= &[&[1, 2, 3], &[4, 5], &[6, 7, 8, 9]]; // workter thread 1 let (t1_send, t1_recv) = mpsc::channel::<Option<Vec<&i32>>>(); thread::spawn(move || { while let Some(p) = t1_recv.recv().unwrap() { println!("Thread1: {:?}", p); } println!("Thread1 is done"); }); // worker thread 2 let (t2_send, t2_recv) = mpsc::channel::<Option<Vec<&i32>>>(); thread::spawn(move || { while let Some(p) = t2_recv.recv().unwrap() { println!("Thread2: {:?}", p); } println!("Thread2 is done"); }); let consumers = vec![t1_send, t2_send]; // main thread that generate result thread::spawn(move || { use std::time::Instant; let cart = CartesianProductIterator::new(data); let mut counter = 0; let timer = Instant::now(); cart.into_iter().for_each(|p| { println!("{:?}", p); consumers.iter().for_each(|c| { c.send(Some(p.to_owned())).unwrap(); }); counter += 1; }); consumers.iter().for_each(|c| { c.send(None).unwrap(); // Explicitly terminate all workers }); println!("Main: Done {} products in {:?}", counter, timer.elapsed()); }).join().unwrap(); } #[test] fn test_unsafe_shared_k_permutation_result_fn() { use std::fmt::Debug; trait Consumer { fn consume(&self); } struct Worker1<'a, T : 'a> { data : &'a[&'a T] } impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { fn consume(&self) { println!("Work1 has {:?}", self.data); } } struct Worker2<'a, T : 'a> { data : &'a[&'a T] } impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { fn consume(&self) { println!("Work2 has {:?}", self.data); } } unsafe fn start_k_permutation_process<'a>(data : &'a[i32], cur_result : *mut [&'a i32], k : usize, consumers : Vec<Box<dyn Consumer + 'a>>) { unsafe_k_permutation(data, k, cur_result, || { consumers.iter().for_each(|c| { c.consume(); }) }); } let k = 3; let data = &[1, 2, 3, 4, 5]; let mut result = vec![&data[0]; k]; unsafe { let shared = result.as_mut_slice() as *mut [&i32]; let worker1 = Worker1 { data : &result }; let worker2 = Worker2 { data : &result }; let consumers : Vec<Box<dyn Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; start_k_permutation_process(data, shared, k, consumers); } } #[test] fn test_shared_k_permutation_result_fn() { use std::fmt::Debug; trait Consumer { fn consume(&self); } struct Worker1<'a, T : 'a> { data : Rc<RefCell<&'a mut[&'a T]>> } impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { fn consume(&self) { println!("Work1 has {:?}", self.data.borrow()); } } struct Worker2<'a, T : 'a> { data : Rc<RefCell<&'a mut[&'a T]>> } impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { fn consume(&self) { println!("Work2 has {:?}", self.data.borrow()); } } fn start_k_permutation_process<'a>(data : &'a[i32], cur_result : Rc<RefCell<&'a mut [&'a i32]>>, k : usize, consumers : Vec<Box<dyn Consumer + 'a>>) { use std::time::Instant; let timer = Instant::now(); let mut counter = 0; k_permutation_cell(data, k, cur_result, || { consumers.iter().for_each(|c| { c.consume(); }); counter += 1; }); println!("Total {} permutation done in {:?}", counter, timer.elapsed()); } let k = 3; let data = &[1, 2, 3, 4, 5]; let mut result = vec![&data[0]; k]; let shared = Rc::new(RefCell::new(result.as_mut_slice())); let worker1 = Worker1 { data : Rc::clone(&shared) }; let worker2 = Worker2 { data : Rc::clone(&shared) }; let consumers : Vec<Box<dyn Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; start_k_permutation_process(data, shared, k, consumers); } #[allow(non_snake_case)] #[test] fn test_shared_KPermutation_result() { use std::time::Instant; use std::fmt::Debug; trait Consumer { fn consume(&self); } struct Worker1<'a, T : 'a> { data : Rc<RefCell<&'a mut[&'a T]>> } impl<'a, T : 'a + Debug> Consumer for Worker1<'a, T> { fn consume(&self) { println!("Work1 has {:?}", self.data.borrow()); } } struct Worker2<'a, T : 'a> { data : Rc<RefCell<&'a mut[&'a T]>> } impl<'a, T : 'a + Debug> Consumer for Worker2<'a, T> { fn consume(&self) { println!("Work2 has {:?}", self.data.borrow()); } } let k = 3; let data = &[1, 2, 3, 4, 5]; let mut result = vec![&data[0]; k]; let shared = Rc::new(RefCell::new(result.as_mut_slice())); let worker1 = Worker1 { data : Rc::clone(&shared) }; let worker2 = Worker2 { data : Rc::clone(&shared) }; let consumers : Vec<Box<dyn Consumer>> = vec![Box::new(worker1), Box::new(worker2)]; let kperm = KPermutationCellIter::new(data, k, shared); let timer = Instant::now(); let mut counter = 0; for _ in kperm { consumers.iter().for_each(|c| {c.consume();}); counter += 1; } println!("Total {} permutation done in {:?}", counter, timer.elapsed()); assert_eq!(counter, divide_factorial(data.len(), data.len() - k)); } #[test] fn test_shared_k_permutation_sync_fn() { fn start_k_permutation_process<'a>(data : &'a[i32], cur_result : Arc<RwLock<Vec<&'a i32>>>, k : usize, notifier : Vec<SyncSender<Option<()>>>, release_recv : Receiver<()>) { use std::time::Instant; let timer = Instant::now(); let mut counter = 0; k_permutation_sync(data, k, cur_result, || { notifier.iter().for_each(|n| { n.send(Some(())).unwrap(); // notify every thread that new data available }); for _ in 0..notifier.len() { release_recv.recv().unwrap(); // block until all thread reading data notify on read completion } counter += 1; }); notifier.iter().for_each(|n| {n.send(None).unwrap()}); // notify every thread that there'll be no more data. println!("Done {} combinations with 2 workers in {:?}", counter, timer.elapsed()); } let k = 4; let data = &[1, 2, 3, 4, 5, 6]; let result = vec![&data[0]; k]; let result_sync = Arc::new(RwLock::new(result)); // workter thread 1 let (t1_send, t1_recv) = mpsc::sync_channel::<Option<()>>(0); let (main_send, main_recv) = mpsc::sync_channel(0); let t1_local = main_send.clone(); let t1_dat = Arc::clone(&result_sync); thread::spawn(move || { while let Some(_) = t1_recv.recv().unwrap() { let _result : &Vec<&i32> = &*t1_dat.read().unwrap(); // println!("Thread1: {:?}", _result); t1_local.send(()).unwrap(); // notify generator thread that reference is no longer neeed. } println!("Thread1 is done"); }); // worker thread 2 let (t2_send, t2_recv) = mpsc::sync_channel::<Option<()>>(0); let t2_dat = Arc::clone(&result_sync); let t2_local = main_send.clone(); thread::spawn(move || { while let Some(_) = t2_recv.recv().unwrap() { let _result : &Vec<&i32> = &*t2_dat.read().unwrap(); // println!("Thread2: {:?}", _result); t2_local.send(()).unwrap(); // notify generator thread that reference is no longer neeed. } println!("Thread2 is done"); }); // main thread that generate result thread::spawn(move || { start_k_permutation_process(data, result_sync, k, vec![t1_send, t2_send], main_recv); }).join().unwrap(); } #[allow(non_snake_case)] #[test] fn test_share_result_KPermutation_iterator_sync() { let k = 3; let data : &[i32] = &[1, 2, 3, 4, 5]; // workter thread 1 let (t1_send, t1_recv) = mpsc::sync_channel::<Option<Vec<&i32>>>(0); thread::spawn(move || { while let Some(c) = t1_recv.recv().unwrap() { let _result : Vec<&i32> = c; println!("Thread1: {:?}", _result); } println!("Thread1 is done"); }); // worker thread 2 let (t2_send, t2_recv) = mpsc::sync_channel::<Option<Vec<&i32>>>(0); thread::spawn(move || { while let Some(c) = t2_recv.recv().unwrap() { let _result : Vec<&i32> = c; println!("Thread2: {:?}", _result); } println!("Thread2 is done"); }); let channels = vec![t1_send, t2_send]; // main thread that generate result thread::spawn(move || { use std::time::Instant; let timer = Instant::now(); let mut counter = 0; let kperm = KPermutationIterator::new(data, k); kperm.into_iter().for_each(|c| { channels.iter().for_each(|t| {t.send(Some(c.to_owned())).unwrap();}); counter += 1; }); channels.iter().for_each(|t| {t.send(None).unwrap()}); println!("Done {} combinations in {:?}", counter, timer.elapsed()); assert_eq!(counter, divide_factorial(data.len(), data.len() - k)); }).join().unwrap(); } #[test] fn test_unsafe_cartesian_product() { use std::time::Instant; let set = (1..4).map(|item| item).collect::<Vec<u64>>(); let mut data = Vec::<&[u64]>::new(); for _ in 0..3 { data.push(&set); } let mut counter = 0; let mut result = vec![&data[0][0]; data.len()]; let result_ptr = result.as_mut_slice() as *mut [&u64]; let timer = Instant::now(); unsafe { unsafe_cartesian_product(&data, result_ptr, || { // println!("{:?}", product); counter += 1; }); } println!("Total {} product done in {:?}", counter, timer.elapsed()); } #[allow(unused)] #[test] fn test_unsafe_k_permutation() { use std::time::{Instant}; let data = [1, 2, 3, 4, 5]; let k = 3; let mut counter = 0; let mut result = vec![&data[0]; k]; let timer = Instant::now(); unsafe { unsafe_k_permutation(&data, k, result.as_mut_slice() as *mut [&usize], || { // uncomment line below to print all k-permutation println!("test_unsafe_k_permutation: {}:{:?}", counter, result); counter += 1; }); } println!("test_unsafe_k_permutation: Total {} permutations done in {:?}", counter, timer.elapsed()); assert_eq!(divide_factorial(data.len(), data.len() - k), counter); } #[test] fn test_tldr_case() { let domains : &[&[i32]] = &[&[1, 2], &[3, 4, 5], &[6], &[7, 8], &[9, 10, 11]]; domains.cart_prod().for_each(|cp| { // each cp will be &[&i32] with length equals to domains.len() which in this case 5 // It's k-permutation of size 3 over data. cp.combination(3).for_each(|mut c| { // need mut // start permute the 3-combination c.permutation().for_each(|p| { // print each permutation of the 3-combination. println!("TLDR: {:?}", p); }); // It'll print the last 3-permutation again because permutation permute the value in place. println!("TLDR: {:?}", c); }) }); } #[test] fn test_x_permutation() { let data = vec![1, 2, 3, 4]; let mut counter = 0; x_permutation(&data, |_| true, |p| { println!("{:?}", p); counter += 1; }); assert_eq!(factorial(data.len()), counter); } #[test] fn test_x_permutation_cell() { let data = vec![1, 2, 3, 4]; let mut result = vec![&data[0]; data.len()]; let share = Rc::new(RefCell::new(result.as_mut_slice())); let mut counter = 0; x_permutation_cell(&data, Rc::clone(&share), |_| true, || { println!("{:?}", &*share.borrow()); counter += 1; }); assert_eq!(factorial(data.len()), counter); } #[test] fn test_x_permutation_sync() { let data = vec![1, 2, 3, 4]; let result = vec![&data[0]; data.len()]; let share = Arc::new(RwLock::new(result)); let mut counter = 0; x_permutation_sync(&data, Arc::clone(&share), |_| true, || { println!("{:?}", &*share.read().unwrap()); counter += 1; }); assert_eq!(factorial(data.len()), counter); } #[test] fn test_unsafe_x_permutation() { let data = vec![1u8, 2, 3, 4]; let mut result = vec![&data[0]; data.len()]; let share = result.as_mut_slice() as *mut [&u8]; let mut counter = 0; unsafe { unsafe_x_permutation(&data, share, |_| true, || { println!("{:?}", result); counter += 1; }); } assert_eq!(factorial(data.len()), counter); } #[test] fn test_x_permutation_restricted() { let data : Vec<u8> = vec![1, 2, 3, 4]; let mut counter = 0; x_permutation(&data, |f| { *f[0] != 1u8 // filter all permutation that start with 1 }, |p| { println!("{:?}", p); counter += 1; }); assert_eq!(factorial(data.len()) - factorial(data.len() - 1), counter); } #[test] #[ignore] fn test_lex_family() { let data : &[&[u8]] = &[&[1, 2, 3], &[4, 5], &[6, 7], &[8, 9], &[10]]; let k = 3; data.cart_prod().for_each(|cp| { // lexicographically ordered cartesian product in `cp` LargeCombinationIterator::new(&cp, k).for_each(|co| { // lexicographically ordered combination of length 3 x_permutation(&co, |_| true, |p| { // lexicographically ordered permutation println!("{:?}", p); }); }); }); // generate k-permutation that first element is even number out of // cartesian product. data.cart_prod().for_each(|cp| { // lexicographically ordered cartesian product in `cp` LargeCombinationIterator::new(&cp, k).for_each(|co| { // lexicographically ordered combination of length 3 x_permutation( &co, |v| ***v[0] & 1 != 1, |p| { // lexicographically ordered permutation println!("{:?}", p); }); }); }); } #[test] #[ignore] fn compare_gosper_custom_fn() { use std::time::Instant; let data : Vec<i32> = (0..30i32).map(|i| {i}).collect(); let r = 20; let mut counter = 0; let timer = Instant::now(); combination(&data, r, |_c| {counter += 1}); println!("Stanford comb {} combination done in {:?}", counter, timer.elapsed()); counter = 0; let timer = Instant::now(); large_combination(&data, r, |_c| {counter += 1}); println!("Custom comb {} combination done in {:?}", counter, timer.elapsed()); } #[test] #[ignore] fn compare_gosper_custom_iter() { use std::time::Instant; let data : Vec<i32> = (0..30i32).map(|i| {i}).collect(); let r = 20; let mut counter = 0; let timer = Instant::now(); let stanford = GosperCombinationIterator::new(&data, r); stanford.into_iter().for_each(|_c| {counter += 1}); println!("Stanford comb {} combination done in {:?}", counter, timer.elapsed()); counter = 0; let timer = Instant::now(); let mut lc = LargeCombinationIterator::new(&data, r); lc.iter().for_each(|_c| {counter += 1}); println!("Custom comb {} combination done in {:?}", counter, timer.elapsed()); } #[test] #[ignore] fn compare_gosper_custom_cell_iter() { use std::time::Instant; let data : Vec<i32> = (0..30i32).map(|i| {i}).collect(); let r = 20; let mut result = vec![&data[0]; r]; let share : Rc<RefCell<&mut[&i32]>> = Rc::new(RefCell::new(&mut result)); let mut counter = 0; let timer = Instant::now(); let stanford = GosperCombinationCellIter::new(&data, r, Rc::clone(&share)); stanford.into_iter().for_each(|_c| {counter += 1}); println!("Stanford comb {} combination done in {:?}", counter, timer.elapsed()); counter = 0; let timer = Instant::now(); let mut lc = LargeCombinationCellIter::new(&data, r, Rc::clone(&share)); lc.iter().for_each(|_c| {counter += 1}); println!("Custom comb {} combination done in {:?}", counter, timer.elapsed()); } #[test] #[ignore] fn compare_gosper_custom_ref_iter() { use std::time::Instant; let data : Vec<i32> = (0..30i32).map(|i| {i}).collect(); let r = 20; let mut result = vec![&data[0]; r]; let share = result.as_mut_slice() as *mut [&i32]; unsafe { let mut counter = 0; let timer = Instant::now(); let stanford = GosperCombinationRefIter::new(&data, r, share); stanford.into_iter().for_each(|_c| {counter += 1}); println!("Stanford comb {} combination done in {:?}", counter, timer.elapsed()); counter = 0; let timer = Instant::now(); let mut lc = LargeCombinationRefIter::new(&data, r, share); lc.iter().for_each(|_c| {counter += 1}); println!("Custom comb {} combination done in {:?}", counter, timer.elapsed()); } } #[test] #[ignore] fn bench_heap_fn() { use std::time::Instant; let mut data : Vec<i32> = (0..10i32).map(|i| {i}).collect(); let timer = Instant::now(); let mut counter = 0; heap_permutation(data.as_mut_slice(), |_p| {counter += 1}); println!("Total {} permutations done in {:?}", counter, timer.elapsed()); } #[test] #[ignore] fn bench_heap_iter() { use std::time::Instant; let mut data : Vec<i32> = (0..10i32).map(|i| {i}).collect(); let timer = Instant::now(); let mut counter = 0; data.permutation().for_each(|_p| {counter += 1}); println!("Total {} permutations done in {:?}", counter, timer.elapsed()); } #[test] #[ignore] fn bench_k_perm_fn() { use std::time::Instant; let data : Vec<i32> = (0..13i32).map(|i| {i}).collect(); let timer = Instant::now(); let mut counter = 0; k_permutation(data.as_slice(), 7, |_p| {counter += 1}); println!("Total {} permutations done in {:?}", counter, timer.elapsed()); } #[test] #[ignore] fn bench_k_perm_iter() { use std::time::Instant; let data : Vec<i32> = (0..13i32).map(|i| {i}).collect(); let timer = Instant::now(); let mut counter = 0; (data.as_slice(), 7usize).permutation().for_each(|_p| {counter += 1}); println!("Total {} permutations done in {:?}", counter, timer.elapsed()); } #[test] #[ignore] fn bench_cart_fn() { use std::time::Instant; let domain : Vec<i32> = (0..5i32).map(|i| {i}).collect(); let domains : Vec<&[i32]> = (0..10).map(|_| domain.as_slice()).collect(); let timer = Instant::now(); let mut counter = 0; cartesian_product(domains.as_slice(), |_p| {counter += 1}); println!("Total {} permutations done in {:?}", counter, timer.elapsed()); } #[test] #[ignore] fn bench_cart_iter() { use std::time::Instant; let domain : Vec<i32> = (0..5i32).map(|i| {i}).collect(); let domains : Vec<&[i32]> = (0..10).map(|_| domain.as_slice()).collect(); let timer = Instant::now(); let mut counter = 0; domains.as_slice().cart_prod().for_each(|_p| {counter += 1}); println!("Total {} permutations done in {:?}", counter, timer.elapsed()); } #[test] #[ignore] fn bench_x_perm_st_fn() { // st mean single thread use std::time::Instant; let mut data : Vec<u8> = (0..13u8).map(|v| v).collect(); let mut counter = 0; let timer = Instant::now(); x_permutation(&data, |_| true, |_p| { counter += 1; }); println!("Done {} x_permutation in {:?}", counter, timer.elapsed()); counter = 0; let timer = Instant::now(); heap_permutation(&mut data, |_p| { counter += 1; }); println!("Done {} heap_permutation in {:?}", counter, timer.elapsed()); } #[test] #[ignore] fn bench_x_perm_mt_fn() { // st mean single thread use std::time::{Duration, Instant}; let mut data : Vec<u8> = (0..13u8).map(|v| v).collect(); let threads = 3usize; let chunk = data.len() / threads; // split data into 3 threads. let complete_count = Arc::new(RwLock::new(0u64)); let total_counter = Arc::new(RwLock::new(0u64)); for i in 0..threads { let u_bound = match i { j if j == threads - 1 => data.len() as u8, // last thread do all the rest _ => (chunk * (i + 1)) as u8 }; let l_bound = (chunk * i) as u8; println!("thread{}: {}-{}", i, l_bound, u_bound); let perm = get_permutation_for(&data, data.len(), l_bound as usize).unwrap(); let t_dat : Vec<u8> = perm.iter().map(|v| **v).collect(); // need to move to each thread let t_counter = Arc::clone(&complete_count); // thread completed count let loc_counter = Arc::clone(&total_counter); // count number of permutation thread::spawn(move || { let mut counter = 0u64; x_permutation(&t_dat, |v| { *v[0] >= l_bound && *v[0] < u_bound }, |_p| { counter += 1; }); *loc_counter.write().unwrap() += counter; println!("Done {} in local thread", counter); *t_counter.write().unwrap() += 1; }); } let main = thread::spawn(move || { let timer = Instant::now(); loop { if *complete_count.read().unwrap() != (threads as u64) { thread::sleep(Duration::from_millis(100)); } else { println!("Done {} x_permutation {} threads in {:?}", &*total_counter.read().unwrap(), threads, timer.elapsed()); break; } } }); main.join().unwrap(); let mut counter = 0u64; let timer = Instant::now(); heap_permutation(&mut data, |_p| { counter += 1; }); println!("Done {} heap_permutation in {:?}", counter, timer.elapsed()); } }