# Crate permutator

Expand description

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());
}``````

## Found a bug ?

Open issue at Github

## Modules

A module that perform everything in copy fashion. There is no Heap permutation family function in here because that function family already return a slice of value.

## Structs

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() function that return itself.

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() function that return itself.

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() function that return itself.

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.

Heap’s permutation in iterator style implementation.

An unsafe Heap’s permutation in iterator style implementation.

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.

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.

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.

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]>>.

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.

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].

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() function that return itself.

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() function that return itself.

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() function that return itself.

A lexicographic ordered permutation based on “Algoritm X” published by Donald E. Knuth. page 20.

A lexicographic ordered permutation based on “Algoritm X” published by Donald E. Knuth. page 20.

A lexicographic ordered permutation based on “Algoritm X” published by Donald E. Knuth. page 20.

## Traits

Create a cartesian product out of `T`. For example,

Create a combination out of `T` Normally, it take a `[T]` or `Vec<T>` to create a combination.

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

Create a permutation iterator that permute data in place. Built-in implementation return an object of HeapPermutation for slice/array and Vec. It return an object of HeapPermutationCellIter on data type of `Rc<RefCell<&mut [T]>>`.

## Functions

Create a cartesian product over given slice. The result will be a slice of borrowed `T`.

Similar to safe cartesian_product function 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.

Similar to safe cartesian_product function 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.

Deprecated

Deprecated

Deprecated

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.

Calculate factorial from given value.

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]

Calculate all possible cartesian combination size. It is always equals to size.pow(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].

Calculate all possible number of permutation. It’s equals to size!/(size - 1).

Heap permutation which permutate variable `d` in place and call `cb` function for each permutation done on `d`.

Heap permutation which permutate variable `d` in place and call `cb` function for each permutation done on `d`.

Heap permutation which permutate variable `d` in place and call `cb` function for each permutation done on `d`.

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]

Similar to safe k_permutation function 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.

Similar to safe k_permutation function 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.

Generate a r-combination from given domain and call callback function on each combination.

Generate a r-combination from given domain and call callback function on each combination. The result will be return into Rc<RefCell<>>.

Generate a r-combination from given domain and call callback function on each combination. The result will be return into Arc<RwLock<>>.

Calculate two factorial multiply on each other. It’ll try to reduce calculation time by calculate the common value only once.

Create a cartesian product over itself. The result will be a slice of borrowed `T`.

Similar to safe cartesian_product function 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.

Similar to safe self_cartesian_product function 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.

Similar to safe cartesian_product function 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.

Deprecated

Similar to safe k_permutation function 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.

Generate a r-combination from given domain and call callback function on each combination. The result will be return into ref mut pointer.

Similar to safe self_cartesian_product function 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.

A lexicographic ordered permutation based on “Algoritm X” published by Donald E. Knuth. page 20.

A lexicographic ordered permutation based on “Algoritm X” published by Donald E. Knuth. page 20.

A lexicographic ordered permutation based on “Algoritm X” published by Donald E. Knuth. page 20.

A lexicographic ordered permutation based on “Algoritm X” published by Donald E. Knuth. page 20.

## Type Definitions

A type that represent a cartesian product of the slice over slices and return result into Rc<RefCell<&mut [&T]>> by using CartesianProductCellIter

A pair of source and sink to get a sharable combination.

A pair of source and sink to get a sharable combination.

A tuples of 3 parameters that allow `Permutation` trait to create k-permutation iterator from it.

A tuple of 3 parameters that allow `Permutation` trait to create k-permutation ref iterator from it.

A pair of parameter that allow `Permutation` trait to create k-permutation iterator from it.

A type that used exclusively for trait CartesianProduct. It return SelfCartesianProductIterator.