Struct rayon::iter::Fold

#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
pub struct Fold<I, ID, F> { /* fields omitted */ }

Fold is an iterator that applies a function over an iterator producing a single value. This struct is created by the fold() method on ParallelIterator

Trait Implementations

impl<U, I, ID, F> ParallelIterator for Fold<I, ID, F> where
    I: ParallelIterator,
    F: Fn(U, I::Item) -> U + Sync + Send,
    ID: Fn() -> U + Sync + Send,
    U: Send, 

type Item = U

The type of item that this parallel iterator produces. For example, if you use the [for_each] method, this is the type of item that your closure will be invoked with.

fn drive_unindexed<C>(self, consumer: C) -> C::Result where
    C: UnindexedConsumer<Self::Item>, 

Internal method used to define the behavior of this parallel iterator. You should not need to call this directly.

fn for_each<OP>(self, op: OP) where
    OP: Fn(Self::Item) + Sync + Send, 

Executes OP on each item produced by the iterator, in parallel.

fn for_each_with<OP, T>(self, init: T, op: OP) where
    OP: Fn(&mut T, Self::Item) + Sync + Send,
    T: Send + Clone, 

Executes OP on the given init value with each item produced by the iterator, in parallel.

fn for_each_init<OP, INIT, T>(self, init: INIT, op: OP) where
    OP: Fn(&mut T, Self::Item) + Sync + Send,
    INIT: Fn() -> T + Sync + Send, 

Executes OP on a value returned by init with each item produced by the iterator, in parallel.

fn try_for_each<OP, R>(self, op: OP) -> R where
    OP: Fn(Self::Item) -> R + Sync + Send,
    R: Try<Ok = ()> + Send, 

Executes a fallible OP on each item produced by the iterator, in parallel.

fn try_for_each_with<OP, T, R>(self, init: T, op: OP) -> R where
    OP: Fn(&mut T, Self::Item) -> R + Sync + Send,
    T: Send + Clone,
    R: Try<Ok = ()> + Send, 

Executes a fallible OP on the given init value with each item produced by the iterator, in parallel.

fn try_for_each_init<OP, INIT, T, R>(self, init: INIT, op: OP) -> R where
    OP: Fn(&mut T, Self::Item) -> R + Sync + Send,
    INIT: Fn() -> T + Sync + Send,
    R: Try<Ok = ()> + Send, 

Executes a fallible OP on a value returned by init with each item produced by the iterator, in parallel.

fn count(self) -> usize

Counts the number of items in this parallel iterator.

fn map<F, R>(self, map_op: F) -> Map<Self, F> where
    F: Fn(Self::Item) -> R + Sync + Send,
    R: Send, 

Applies map_op to each item of this iterator, producing a new iterator with the results.

fn map_with<F, T, R>(self, init: T, map_op: F) -> MapWith<Self, T, F> where
    F: Fn(&mut T, Self::Item) -> R + Sync + Send,
    T: Send + Clone,
    R: Send, 

Applies map_op to the given init value with each item of this iterator, producing a new iterator with the results.

fn map_init<F, INIT, T, R>(
    self,
    init: INIT,
    map_op: F
) -> MapInit<Self, INIT, F> where
    F: Fn(&mut T, Self::Item) -> R + Sync + Send,
    INIT: Fn() -> T + Sync + Send,
    R: Send, 

Applies map_op to a value returned by init with each item of this iterator, producing a new iterator with the results.

fn cloned<'a, T>(self) -> Cloned<Self> where
    T: 'a + Clone + Send,
    Self: ParallelIterator<Item = &'a T>, 

Creates an iterator which clones all of its elements. This may be useful when you have an iterator over &T, but you need T.

fn inspect<OP>(self, inspect_op: OP) -> Inspect<Self, OP> where
    OP: Fn(&Self::Item) + Sync + Send, 

Applies inspect_op to a reference to each item of this iterator, producing a new iterator passing through the original items. This is often useful for debugging to see what's happening in iterator stages.

fn update<F>(self, update_op: F) -> Update<Self, F> where
    F: Fn(&mut Self::Item) + Sync + Send, 

Mutates each item of this iterator before yielding it.

fn filter<P>(self, filter_op: P) -> Filter<Self, P> where
    P: Fn(&Self::Item) -> bool + Sync + Send, 

Applies filter_op to each item of this iterator, producing a new iterator with only the items that gave true results.

fn filter_map<P, R>(self, filter_op: P) -> FilterMap<Self, P> where
    P: Fn(Self::Item) -> Option<R> + Sync + Send,
    R: Send, 

Applies filter_op to each item of this iterator to get an Option, producing a new iterator with only the items from Some results.

fn flat_map<F, PI>(self, map_op: F) -> FlatMap<Self, F> where
    F: Fn(Self::Item) -> PI + Sync + Send,
    PI: IntoParallelIterator, 

Applies map_op to each item of this iterator to get nested iterators, producing a new iterator that flattens these back into one.

fn flatten(self) -> Flatten<Self> where
    Self::Item: IntoParallelIterator, 

An adaptor that flattens iterable Items into one large iterator

fn reduce<OP, ID>(self, identity: ID, op: OP) -> Self::Item where
    OP: Fn(Self::Item, Self::Item) -> Self::Item + Sync + Send,
    ID: Fn() -> Self::Item + Sync + Send, 

Reduces the items in the iterator into one item using op. The argument identity should be a closure that can produce "identity" value which may be inserted into the sequence as needed to create opportunities for parallel execution. So, for example, if you are doing a summation, then identity() ought to produce something that represents the zero for your type (but consider just calling sum() in that case).

fn reduce_with<OP>(self, op: OP) -> Option<Self::Item> where
    OP: Fn(Self::Item, Self::Item) -> Self::Item + Sync + Send, 

Reduces the items in the iterator into one item using op. If the iterator is empty, None is returned; otherwise, Some is returned.

fn try_reduce<T, OP, ID>(self, identity: ID, op: OP) -> Self::Item where
    OP: Fn(T, T) -> Self::Item + Sync + Send,
    ID: Fn() -> T + Sync + Send,
    Self::Item: Try<Ok = T>, 

Reduces the items in the iterator into one item using a fallible op. The identity argument is used the same way as in [reduce()].

fn try_reduce_with<T, OP>(self, op: OP) -> Option<Self::Item> where
    OP: Fn(T, T) -> Self::Item + Sync + Send,
    Self::Item: Try<Ok = T>, 

Reduces the items in the iterator into one item using a fallible op.

fn fold<T, ID, F>(self, identity: ID, fold_op: F) -> Fold<Self, ID, F> where
    F: Fn(T, Self::Item) -> T + Sync + Send,
    ID: Fn() -> T + Sync + Send,
    T: Send, 

Parallel fold is similar to sequential fold except that the sequence of items may be subdivided before it is folded. Consider a list of numbers like 22 3 77 89 46. If you used sequential fold to add them (fold(0, |a,b| a+b), you would wind up first adding 0 + 22, then 22 + 3, then 25 + 77, and so forth. The parallel fold works similarly except that it first breaks up your list into sublists, and hence instead of yielding up a single sum at the end, it yields up multiple sums. The number of results is nondeterministic, as is the point where the breaks occur.

fn fold_with<F, T>(self, init: T, fold_op: F) -> FoldWith<Self, T, F> where
    F: Fn(T, Self::Item) -> T + Sync + Send,
    T: Send + Clone, 

Applies fold_op to the given init value with each item of this iterator, finally producing the value for further use.

fn try_fold<T, R, ID, F>(
    self,
    identity: ID,
    fold_op: F
) -> TryFold<Self, R, ID, F> where
    F: Fn(T, Self::Item) -> R + Sync + Send,
    ID: Fn() -> T + Sync + Send,
    R: Try<Ok = T> + Send, 

Perform a fallible parallel fold.

fn try_fold_with<F, T, R>(self, init: T, fold_op: F) -> TryFoldWith<Self, R, F> where
    F: Fn(T, Self::Item) -> R + Sync + Send,
    R: Try<Ok = T> + Send,
    T: Clone + Send, 

Perform a fallible parallel fold with a cloneable init value.

fn sum<S>(self) -> S where
    S: Send + Sum<Self::Item> + Sum<S>, 

Sums up the items in the iterator.

fn product<P>(self) -> P where
    P: Send + Product<Self::Item> + Product<P>, 

Multiplies all the items in the iterator.

fn min(self) -> Option<Self::Item> where
    Self::Item: Ord, 

Computes the minimum of all the items in the iterator. If the iterator is empty, None is returned; otherwise, Some(min) is returned.

fn min_by<F>(self, f: F) -> Option<Self::Item> where
    F: Sync + Send + Fn(&Self::Item, &Self::Item) -> Ordering, 

Computes the minimum of all the items in the iterator with respect to the given comparison function. If the iterator is empty, None is returned; otherwise, Some(min) is returned.

fn min_by_key<K, F>(self, f: F) -> Option<Self::Item> where
    K: Ord + Send,
    F: Sync + Send + Fn(&Self::Item) -> K, 

Computes the item that yields the minimum value for the given function. If the iterator is empty, None is returned; otherwise, Some(item) is returned.

fn max(self) -> Option<Self::Item> where
    Self::Item: Ord, 

Computes the maximum of all the items in the iterator. If the iterator is empty, None is returned; otherwise, Some(max) is returned.

fn max_by<F>(self, f: F) -> Option<Self::Item> where
    F: Sync + Send + Fn(&Self::Item, &Self::Item) -> Ordering, 

Computes the maximum of all the items in the iterator with respect to the given comparison function. If the iterator is empty, None is returned; otherwise, Some(min) is returned.

fn max_by_key<K, F>(self, f: F) -> Option<Self::Item> where
    K: Ord + Send,
    F: Sync + Send + Fn(&Self::Item) -> K, 

Computes the item that yields the maximum value for the given function. If the iterator is empty, None is returned; otherwise, Some(item) is returned.

fn chain<C>(self, chain: C) -> Chain<Self, C::Iter> where
    C: IntoParallelIterator<Item = Self::Item>, 

Takes two iterators and creates a new iterator over both.

fn find_any<P>(self, predicate: P) -> Option<Self::Item> where
    P: Fn(&Self::Item) -> bool + Sync + Send, 

Searches for some item in the parallel iterator that matches the given predicate and returns it. This operation is similar to [find on sequential iterators][find] but the item returned may not be the first one in the parallel sequence which matches, since we search the entire sequence in parallel.

fn find_first<P>(self, predicate: P) -> Option<Self::Item> where
    P: Fn(&Self::Item) -> bool + Sync + Send, 

Searches for the sequentially first item in the parallel iterator that matches the given predicate and returns it.

fn find_last<P>(self, predicate: P) -> Option<Self::Item> where
    P: Fn(&Self::Item) -> bool + Sync + Send, 

Searches for the sequentially last item in the parallel iterator that matches the given predicate and returns it.

fn find_map_any<P, R>(self, predicate: P) -> Option<R> where
    P: Fn(Self::Item) -> Option<R> + Sync + Send,
    R: Send, 

Applies the given predicate to the items in the parallel iterator and returns any non-None result of the map operation.

fn find_map_first<P, R>(self, predicate: P) -> Option<R> where
    P: Fn(Self::Item) -> Option<R> + Sync + Send,
    R: Send, 

Applies the given predicate to the items in the parallel iterator and returns the sequentially first non-None result of the map operation.

fn find_map_last<P, R>(self, predicate: P) -> Option<R> where
    P: Fn(Self::Item) -> Option<R> + Sync + Send,
    R: Send, 

Applies the given predicate to the items in the parallel iterator and returns the sequentially last non-None result of the map operation.

fn any<P>(self, predicate: P) -> bool where
    P: Fn(Self::Item) -> bool + Sync + Send, 

Searches for some item in the parallel iterator that matches the given predicate, and if so returns true. Once a match is found, we'll attempt to stop process the rest of the items. Proving that there's no match, returning false, does require visiting every item.

fn all<P>(self, predicate: P) -> bool where
    P: Fn(Self::Item) -> bool + Sync + Send, 

Tests that every item in the parallel iterator matches the given predicate, and if so returns true. If a counter-example is found, we'll attempt to stop processing more items, then return false.

fn while_some<T>(self) -> WhileSome<Self> where
    Self: ParallelIterator<Item = Option<T>>,
    T: Send, 

Creates an iterator over the Some items of this iterator, halting as soon as any None is found.

fn panic_fuse(self) -> PanicFuse<Self>

Wraps an iterator with a fuse in case of panics, to halt all threads as soon as possible.

fn collect<C>(self) -> C where
    C: FromParallelIterator<Self::Item>, 

Create a fresh collection containing all the element produced by this parallel iterator.

fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB) where
    Self: ParallelIterator<Item = (A, B)>,
    FromA: Default + Send + ParallelExtend<A>,
    FromB: Default + Send + ParallelExtend<B>,
    A: Send,
    B: Send, 

Unzips the items of a parallel iterator into a pair of arbitrary ParallelExtend containers.

fn partition<A, B, P>(self, predicate: P) -> (A, B) where
    A: Default + Send + ParallelExtend<Self::Item>,
    B: Default + Send + ParallelExtend<Self::Item>,
    P: Fn(&Self::Item) -> bool + Sync + Send, 

Partitions the items of a parallel iterator into a pair of arbitrary ParallelExtend containers. Items for which the predicate returns true go into the first container, and the rest go into the second.

fn partition_map<A, B, P, L, R>(self, predicate: P) -> (A, B) where
    A: Default + Send + ParallelExtend<L>,
    B: Default + Send + ParallelExtend<R>,
    P: Fn(Self::Item) -> Either<L, R> + Sync + Send,
    L: Send,
    R: Send, 

Partitions and maps the items of a parallel iterator into a pair of arbitrary ParallelExtend containers. Either::Left items go into the first container, and Either::Right items go into the second.

fn intersperse(self, element: Self::Item) -> Intersperse<Self> where
    Self::Item: Clone, 

Intersperses clones of an element between items of this iterator.

fn opt_len(&self) -> Option<usize>

Internal method used to define the behavior of this parallel iterator. You should not need to call this directly.

impl<I: Clone, ID: Clone, F: Clone> Clone for Fold<I, ID, F>

fn clone(&self) -> Fold<I, ID, F>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<I: ParallelIterator + Debug, ID, F> Debug for Fold<I, ID, F>

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.