Struct permutator::LargeCombinationRefIter
source · pub struct LargeCombinationRefIter<'a, T>where
T: 'a,{ /* private fields */ }
Expand description
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
Safety
This object took raw mutable pointer and convert in upon object instantiation via new function 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
took about 460ms.
This function is very much alike
unsafe_combination function
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());
}
Implementations
sourceimpl<'a, T> LargeCombinationRefIter<'a, T>
impl<'a, T> LargeCombinationRefIter<'a, T>
pub unsafe fn new(
data: &'a [T],
r: usize,
result: *mut [&'a T]
) -> LargeCombinationRefIter<'a, T>ⓘNotable traits for LargeCombinationRefIter<'a, T>impl<'a, T> Iterator for LargeCombinationRefIter<'a, T> type Item = ();
sourcepub fn len(&self) -> usize
pub fn len(&self) -> usize
Total number of combinations this iterate can return. It will equals to n!/((n-r)!*r!)
pub fn iter(&mut self) -> &mut Self
Trait Implementations
sourceimpl<'a, T> ExactSizeIterator for LargeCombinationRefIter<'a, T>
impl<'a, T> ExactSizeIterator for LargeCombinationRefIter<'a, T>
sourceimpl<'a, T> Iterator for LargeCombinationRefIter<'a, T>
impl<'a, T> Iterator for LargeCombinationRefIter<'a, T>
sourcefn next_chunk<const N: usize>(
&mut self
) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>where
Self: Sized,
fn next_chunk<const N: usize>(
&mut self
) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>where
Self: Sized,
iter_next_chunk
)N
values. Read more1.0.0 · sourcefn size_hint(&self) -> (usize, Option<usize>)
fn size_hint(&self) -> (usize, Option<usize>)
1.0.0 · sourcefn count(self) -> usizewhere
Self: Sized,
fn count(self) -> usizewhere
Self: Sized,
1.0.0 · sourcefn last(self) -> Option<Self::Item>where
Self: Sized,
fn last(self) -> Option<Self::Item>where
Self: Sized,
sourcefn advance_by(&mut self, n: usize) -> Result<(), usize>
fn advance_by(&mut self, n: usize) -> Result<(), usize>
iter_advance_by
)n
elements. Read more1.0.0 · sourcefn nth(&mut self, n: usize) -> Option<Self::Item>
fn nth(&mut self, n: usize) -> Option<Self::Item>
n
th element of the iterator. Read more1.28.0 · sourcefn step_by(self, step: usize) -> StepBy<Self>where
Self: Sized,
fn step_by(self, step: usize) -> StepBy<Self>where
Self: Sized,
1.0.0 · sourcefn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter>where
Self: Sized,
U: IntoIterator<Item = Self::Item>,
fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter>where
Self: Sized,
U: IntoIterator<Item = Self::Item>,
1.0.0 · sourcefn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter>where
Self: Sized,
U: IntoIterator,
fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter>where
Self: Sized,
U: IntoIterator,
sourcefn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>where
Self: Sized,
G: FnMut() -> Self::Item,
fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>where
Self: Sized,
G: FnMut() -> Self::Item,
iter_intersperse
)separator
between adjacent items of the original iterator. Read more1.0.0 · sourcefn map<B, F>(self, f: F) -> Map<Self, F>where
Self: Sized,
F: FnMut(Self::Item) -> B,
fn map<B, F>(self, f: F) -> Map<Self, F>where
Self: Sized,
F: FnMut(Self::Item) -> B,
1.21.0 · sourcefn for_each<F>(self, f: F)where
Self: Sized,
F: FnMut(Self::Item),
fn for_each<F>(self, f: F)where
Self: Sized,
F: FnMut(Self::Item),
1.0.0 · sourcefn filter<P>(self, predicate: P) -> Filter<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,
fn filter<P>(self, predicate: P) -> Filter<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,
1.0.0 · sourcefn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>where
Self: Sized,
F: FnMut(Self::Item) -> Option<B>,
fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>where
Self: Sized,
F: FnMut(Self::Item) -> Option<B>,
1.0.0 · sourcefn enumerate(self) -> Enumerate<Self>where
Self: Sized,
fn enumerate(self) -> Enumerate<Self>where
Self: Sized,
1.0.0 · sourcefn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,
fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,
1.0.0 · sourcefn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,
fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,
1.57.0 · sourcefn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>where
Self: Sized,
P: FnMut(Self::Item) -> Option<B>,
fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>where
Self: Sized,
P: FnMut(Self::Item) -> Option<B>,
1.0.0 · sourcefn skip(self, n: usize) -> Skip<Self>where
Self: Sized,
fn skip(self, n: usize) -> Skip<Self>where
Self: Sized,
n
elements. Read more1.0.0 · sourcefn take(self, n: usize) -> Take<Self>where
Self: Sized,
fn take(self, n: usize) -> Take<Self>where
Self: Sized,
n
elements, or fewer
if the underlying iterator ends sooner. Read more1.0.0 · sourcefn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>where
Self: Sized,
F: FnMut(&mut St, Self::Item) -> Option<B>,
fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>where
Self: Sized,
F: FnMut(&mut St, Self::Item) -> Option<B>,
1.0.0 · sourcefn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>where
Self: Sized,
U: IntoIterator,
F: FnMut(Self::Item) -> U,
fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>where
Self: Sized,
U: IntoIterator,
F: FnMut(Self::Item) -> U,
1.0.0 · sourcefn inspect<F>(self, f: F) -> Inspect<Self, F>where
Self: Sized,
F: FnMut(&Self::Item),
fn inspect<F>(self, f: F) -> Inspect<Self, F>where
Self: Sized,
F: FnMut(&Self::Item),
1.0.0 · sourcefn by_ref(&mut self) -> &mut Selfwhere
Self: Sized,
fn by_ref(&mut self) -> &mut Selfwhere
Self: Sized,
1.0.0 · sourcefn collect<B>(self) -> Bwhere
B: FromIterator<Self::Item>,
Self: Sized,
fn collect<B>(self) -> Bwhere
B: FromIterator<Self::Item>,
Self: Sized,
sourcefn collect_into<E>(self, collection: &mut E) -> &mut Ewhere
E: Extend<Self::Item>,
Self: Sized,
fn collect_into<E>(self, collection: &mut E) -> &mut Ewhere
E: Extend<Self::Item>,
Self: Sized,
iter_collect_into
)1.0.0 · sourcefn partition<B, F>(self, f: F) -> (B, B)where
Self: Sized,
B: Default + Extend<Self::Item>,
F: FnMut(&Self::Item) -> bool,
fn partition<B, F>(self, f: F) -> (B, B)where
Self: Sized,
B: Default + Extend<Self::Item>,
F: FnMut(&Self::Item) -> bool,
sourcefn is_partitioned<P>(self, predicate: P) -> boolwhere
Self: Sized,
P: FnMut(Self::Item) -> bool,
fn is_partitioned<P>(self, predicate: P) -> boolwhere
Self: Sized,
P: FnMut(Self::Item) -> bool,
iter_is_partitioned
)true
precede all those that return false
. Read more1.27.0 · sourcefn try_fold<B, F, R>(&mut self, init: B, f: F) -> Rwhere
Self: Sized,
F: FnMut(B, Self::Item) -> R,
R: Try<Output = B>,
fn try_fold<B, F, R>(&mut self, init: B, f: F) -> Rwhere
Self: Sized,
F: FnMut(B, Self::Item) -> R,
R: Try<Output = B>,
1.27.0 · sourcefn try_for_each<F, R>(&mut self, f: F) -> Rwhere
Self: Sized,
F: FnMut(Self::Item) -> R,
R: Try<Output = ()>,
fn try_for_each<F, R>(&mut self, f: F) -> Rwhere
Self: Sized,
F: FnMut(Self::Item) -> R,
R: Try<Output = ()>,
1.0.0 · sourcefn fold<B, F>(self, init: B, f: F) -> Bwhere
Self: Sized,
F: FnMut(B, Self::Item) -> B,
fn fold<B, F>(self, init: B, f: F) -> Bwhere
Self: Sized,
F: FnMut(B, Self::Item) -> B,
1.51.0 · sourcefn reduce<F>(self, f: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(Self::Item, Self::Item) -> Self::Item,
fn reduce<F>(self, f: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(Self::Item, Self::Item) -> Self::Item,
sourcefn try_reduce<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryTypewhere
Self: Sized,
F: FnMut(Self::Item, Self::Item) -> R,
R: Try<Output = Self::Item>,
<R as Try>::Residual: Residual<Option<Self::Item>>,
fn try_reduce<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryTypewhere
Self: Sized,
F: FnMut(Self::Item, Self::Item) -> R,
R: Try<Output = Self::Item>,
<R as Try>::Residual: Residual<Option<Self::Item>>,
iterator_try_reduce
)1.0.0 · sourcefn all<F>(&mut self, f: F) -> boolwhere
Self: Sized,
F: FnMut(Self::Item) -> bool,
fn all<F>(&mut self, f: F) -> boolwhere
Self: Sized,
F: FnMut(Self::Item) -> bool,
1.0.0 · sourcefn any<F>(&mut self, f: F) -> boolwhere
Self: Sized,
F: FnMut(Self::Item) -> bool,
fn any<F>(&mut self, f: F) -> boolwhere
Self: Sized,
F: FnMut(Self::Item) -> bool,
1.0.0 · sourcefn find<P>(&mut self, predicate: P) -> Option<Self::Item>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,
fn find<P>(&mut self, predicate: P) -> Option<Self::Item>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,
1.30.0 · sourcefn find_map<B, F>(&mut self, f: F) -> Option<B>where
Self: Sized,
F: FnMut(Self::Item) -> Option<B>,
fn find_map<B, F>(&mut self, f: F) -> Option<B>where
Self: Sized,
F: FnMut(Self::Item) -> Option<B>,
sourcefn try_find<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryTypewhere
Self: Sized,
F: FnMut(&Self::Item) -> R,
R: Try<Output = bool>,
<R as Try>::Residual: Residual<Option<Self::Item>>,
fn try_find<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryTypewhere
Self: Sized,
F: FnMut(&Self::Item) -> R,
R: Try<Output = bool>,
<R as Try>::Residual: Residual<Option<Self::Item>>,
try_find
)1.0.0 · sourcefn position<P>(&mut self, predicate: P) -> Option<usize>where
Self: Sized,
P: FnMut(Self::Item) -> bool,
fn position<P>(&mut self, predicate: P) -> Option<usize>where
Self: Sized,
P: FnMut(Self::Item) -> bool,
1.6.0 · sourcefn max_by_key<B, F>(self, f: F) -> Option<Self::Item>where
B: Ord,
Self: Sized,
F: FnMut(&Self::Item) -> B,
fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>where
B: Ord,
Self: Sized,
F: FnMut(&Self::Item) -> B,
1.15.0 · sourcefn max_by<F>(self, compare: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
fn max_by<F>(self, compare: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
1.6.0 · sourcefn min_by_key<B, F>(self, f: F) -> Option<Self::Item>where
B: Ord,
Self: Sized,
F: FnMut(&Self::Item) -> B,
fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>where
B: Ord,
Self: Sized,
F: FnMut(&Self::Item) -> B,
1.15.0 · sourcefn min_by<F>(self, compare: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
fn min_by<F>(self, compare: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
1.0.0 · sourcefn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)where
FromA: Default + Extend<A>,
FromB: Default + Extend<B>,
Self: Sized + Iterator<Item = (A, B)>,
fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)where
FromA: Default + Extend<A>,
FromB: Default + Extend<B>,
Self: Sized + Iterator<Item = (A, B)>,
1.36.0 · sourcefn copied<'a, T>(self) -> Copied<Self>where
T: 'a + Copy,
Self: Sized + Iterator<Item = &'a T>,
fn copied<'a, T>(self) -> Copied<Self>where
T: 'a + Copy,
Self: Sized + Iterator<Item = &'a T>,
1.0.0 · sourcefn cloned<'a, T>(self) -> Cloned<Self>where
T: 'a + Clone,
Self: Sized + Iterator<Item = &'a T>,
fn cloned<'a, T>(self) -> Cloned<Self>where
T: 'a + Clone,
Self: Sized + Iterator<Item = &'a T>,
sourcefn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N>where
Self: Sized,
fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N>where
Self: Sized,
iter_array_chunks
)N
elements of the iterator at a time. Read more1.11.0 · sourcefn sum<S>(self) -> Swhere
Self: Sized,
S: Sum<Self::Item>,
fn sum<S>(self) -> Swhere
Self: Sized,
S: Sum<Self::Item>,
1.11.0 · sourcefn product<P>(self) -> Pwhere
Self: Sized,
P: Product<Self::Item>,
fn product<P>(self) -> Pwhere
Self: Sized,
P: Product<Self::Item>,
sourcefn cmp_by<I, F>(self, other: I, cmp: F) -> Orderingwhere
Self: Sized,
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,
fn cmp_by<I, F>(self, other: I, cmp: F) -> Orderingwhere
Self: Sized,
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,
iter_order_by
)Iterator
with those
of another with respect to the specified comparison function. Read more1.5.0 · sourcefn partial_cmp<I>(self, other: I) -> Option<Ordering>where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Self: Sized,
fn partial_cmp<I>(self, other: I) -> Option<Ordering>where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Self: Sized,
sourcefn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>where
Self: Sized,
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,
fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>where
Self: Sized,
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,
iter_order_by
)Iterator
with those
of another with respect to the specified comparison function. Read more1.5.0 · sourcefn eq<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
Self: Sized,
fn eq<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
Self: Sized,
sourcefn eq_by<I, F>(self, other: I, eq: F) -> boolwhere
Self: Sized,
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,
fn eq_by<I, F>(self, other: I, eq: F) -> boolwhere
Self: Sized,
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,
iter_order_by
)1.5.0 · sourcefn ne<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
Self: Sized,
fn ne<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
Self: Sized,
1.5.0 · sourcefn lt<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Self: Sized,
fn lt<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Self: Sized,
Iterator
are lexicographically
less than those of another. Read more1.5.0 · sourcefn le<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Self: Sized,
fn le<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Self: Sized,
Iterator
are lexicographically
less or equal to those of another. Read more1.5.0 · sourcefn gt<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Self: Sized,
fn gt<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Self: Sized,
Iterator
are lexicographically
greater than those of another. Read more1.5.0 · sourcefn ge<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Self: Sized,
fn ge<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Self: Sized,
Iterator
are lexicographically
greater than or equal to those of another. Read moresourcefn is_sorted_by<F>(self, compare: F) -> boolwhere
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,
fn is_sorted_by<F>(self, compare: F) -> boolwhere
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,
is_sorted
)sourcefn is_sorted_by_key<F, K>(self, f: F) -> boolwhere
Self: Sized,
F: FnMut(Self::Item) -> K,
K: PartialOrd<K>,
fn is_sorted_by_key<F, K>(self, f: F) -> boolwhere
Self: Sized,
F: FnMut(Self::Item) -> K,
K: PartialOrd<K>,
is_sorted
)