ParIterableLike

trait ParIterableLike[+T, +Repr <: ParIterable[T], +Sequential <: scala.Iterable[T] with IterableLike[T, Sequential]] extends GenIterableLike[T, Repr] with CustomParallelizable[T, Repr] with Parallel with HasNewCombiner[T, Repr]

A template trait for parallel collections of type ParIterable[T].

This is a base trait for Scala parallel collections. It defines behaviour common to all parallel collections. Concrete parallel collections should inherit this trait and ParIterable if they want to define specific combiner factories.

Parallel operations are implemented with divide and conquer style algorithms that parallelize well. The basic idea is to split the collection into smaller parts until they are small enough to be operated on sequentially.

All of the parallel operations are implemented as tasks within this trait. Tasks rely on the concept of splitters, which extend iterators. Every parallel collection defines:

def splitter: IterableSplitter[T]

which returns an instance of IterableSplitter[T], which is a subtype of Splitter[T]. Splitters have a method remaining to check the remaining number of elements, and method split which is defined by splitters. Method split divides the splitters iterate over into disjunct subsets:

def split: Seq[Splitter]

which splits the splitter into a sequence of disjunct subsplitters. This is typically a very fast operation which simply creates wrappers around the receiver collection. This can be repeated recursively.

Tasks are scheduled for execution through a scala.collection.parallel.TaskSupport object, which can be changed through the tasksupport setter of the collection.

Method newCombiner produces a new combiner. Combiners are an extension of builders. They provide a method combine which combines two combiners and returns a combiner containing elements of both combiners. This method can be implemented by aggressively copying all the elements into the new combiner or by lazily binding their results. It is recommended to avoid copying all of the elements for performance reasons, although that cost might be negligible depending on the use case. Standard parallel collection combiners avoid copying when merging results, relying either on a two-step lazy construction or specific data-structure properties.

Methods:

def seq: Sequential
def par: Repr

produce the sequential or parallel implementation of the collection, respectively. Method par just returns a reference to this parallel collection. Method seq is efficient - it will not copy the elements. Instead, it will create a sequential version of the collection using the same underlying data structure. Note that this is not the case for sequential collections in general - they may copy the elements and produce a different underlying data structure.

The combination of methods toMap, toSeq or toSet along with par and seq is a flexible way to change between different collection types.

Since this trait extends the GenIterable trait, methods like size must also be implemented in concrete collections, while iterator forwards to splitter by default.

Each parallel collection is bound to a specific fork/join pool, on which dormant worker threads are kept. The fork/join pool contains other information such as the parallelism level, that is, the number of processors used. When a collection is created, it is assigned the default fork/join pool found in the scala.parallel package object.

Parallel collections are not necessarily ordered in terms of the foreach operation (see Traversable). Parallel sequences have a well defined order for iterators - creating an iterator and traversing the elements linearly will always yield the same order. However, bulk operations such as foreach, map or filter always occur in undefined orders for all parallel collections.

Existing parallel collection implementations provide strict parallel iterators. Strict parallel iterators are aware of the number of elements they have yet to traverse. It's also possible to provide non-strict parallel iterators, which do not know the number of elements remaining. To do this, the new collection implementation must override isStrictSplitterCollection to false. This will make some operations unavailable.

To create a new parallel collection, extend the ParIterable trait, and implement size, splitter, newCombiner and seq. Having an implicit combiner factory requires extending this trait in addition, as well as providing a companion object, as with regular collections.

Method size is implemented as a constant time operation for parallel collections, and parallel collection operations rely on this assumption.

The higher-order functions passed to certain operations may contain side-effects. Since implementations of bulk operations may not be sequential, this means that side-effects may not be predictable and may produce data-races, deadlocks or invalidation of state if care is not taken. It is up to the programmer to either avoid using side-effects or to use some form of synchronization when accessing mutable data.

T: the element type of the collection
Repr: the type of the actual collection containing the elements

Self Type: ParIterableLike[T, Repr, Sequential]

Linear Supertypes

HasNewCombiner[T, Repr], Parallel, CustomParallelizable[T, Repr], Parallelizable[T, Repr], GenIterableLike[T, Repr], GenTraversableLike[T, Repr], GenTraversableOnce[T], AnyRef, Any

Known Subclasses

ParIterable, ParMap, WithDefault, ParMapLike, DefaultKeySet, DefaultValuesIterable, ParSeq, ParSeqLike, ParSet, ParSetLike, ParHashMap, ParHashSet, ParIterable, ParMap, WithDefault, ParRange, ParSeq, ParSet, ParVector, ParArray, ParHashMap, ParHashSet, ParIterable, ParMap, WithDefault, ParMapLike, ParSeq, ParSet, ParSetLike, ParTrieMap

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Inherited

ParIterableLike
HasNewCombiner
Parallel
CustomParallelizable
Parallelizable
GenIterableLike
GenTraversableLike
GenTraversableOnce
AnyRef
Any

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Visibility

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Type Members

trait Accessor [R, Tp] extends StrictSplitterCheckTask[R, Tp]
Standard accessor task that iterates over the elements of the collection.
Standard accessor task that iterates over the elements of the collection.
R
type of the result of this method (R for result).
Tp
the representation type of the task at hand.

Attributes
protected
class Aggregate [S] extends Accessor[S, Aggregate[S]]

Attributes
protected[this]
trait BuilderOps [Elem, To] extends AnyRef
class Collect [S, That] extends Transformer[Combiner[S, That], Collect[S, That]]

Attributes
protected[this]
abstract class Composite [FR, SR, R, First <: StrictSplitterCheckTask[FR, _], Second <: StrictSplitterCheckTask[SR, _]] extends NonDivisibleTask[R, Composite[FR, SR, R, First, Second]]

Attributes
protected[this]
class Copy [U >: T, That] extends Transformer[Combiner[U, That], Copy[U, That]]

Attributes
protected
class CopyToArray [U >: T, This >: Repr] extends Accessor[Unit, CopyToArray[U, This]]

Attributes
protected[this]
class Count extends Accessor[Int, Count]

Attributes
protected[this]
class CreateScanTree [U >: T] extends Transformer[ScanTree[U], CreateScanTree[U]]

Attributes
protected[this]
class Drop [U >: T, This >: Repr] extends Transformer[Combiner[U, This], Drop[U, This]]

Attributes
protected[this]
class Exists extends Accessor[Boolean, Exists]

Attributes
protected[this]
class Filter [U >: T, This >: Repr] extends Transformer[Combiner[U, This], Filter[U, This]]

Attributes
protected[this]
class FilterNot [U >: T, This >: Repr] extends Transformer[Combiner[U, This], FilterNot[U, This]]

Attributes
protected[this]
class Find [U >: T] extends Accessor[Option[U], Find[U]]

Attributes
protected[this]
class FlatMap [S, That] extends Transformer[Combiner[S, That], FlatMap[S, That]]

Attributes
protected[this]
class Fold [U >: T] extends Accessor[U, Fold[U]]

Attributes
protected[this]
class Forall extends Accessor[Boolean, Forall]

Attributes
protected[this]
class Foreach [S] extends Accessor[Unit, Foreach[S]]

Attributes
protected[this]
class FromScanTree [U >: T, That] extends StrictSplitterCheckTask[Combiner[U, That], FromScanTree[U, That]]

Attributes
protected[this]
class GroupBy [K, U >: T] extends Transformer[HashMapCombiner[K, U], GroupBy[K, U]]

Attributes
protected[this]
class Map [S, That] extends Transformer[Combiner[S, That], Map[S, That]]

Attributes
protected[this]
class Max [U >: T] extends Accessor[Option[U], Max[U]]

Attributes
protected[this]
class Min [U >: T] extends Accessor[Option[U], Min[U]]

Attributes
protected[this]
trait NonDivisible [R] extends NonDivisibleTask[R, NonDivisible[R]]

Attributes
protected[this]
trait NonDivisibleTask [R, Tp] extends StrictSplitterCheckTask[R, Tp]

Attributes
protected[this]
abstract class ParComposite [FR, SR, R, First <: StrictSplitterCheckTask[FR, _], Second <: StrictSplitterCheckTask[SR, _]] extends Composite[FR, SR, R, First, Second]
Performs two tasks in parallel, and waits for both to finish.
Performs two tasks in parallel, and waits for both to finish.

Attributes
protected[this]
class Partition [U >: T, This >: Repr] extends Transformer[(Combiner[U, This], Combiner[U, This]), Partition[U, This]]

Attributes
protected[this]
class Product [U >: T] extends Accessor[U, Product[U]]

Attributes
protected[this]
class Reduce [U >: T] extends Accessor[Option[U], Reduce[U]]

Attributes
protected[this]
abstract class ResultMapping [R, Tp, R1] extends NonDivisibleTask[R1, ResultMapping[R, Tp, R1]]

Attributes
protected[this]
type SSCTask[R, Tp] = StrictSplitterCheckTask[R, Tp]
case class ScanLeaf [U >: T](pit: IterableSplitter[U], op: (U, U) ⇒ U, from: Int, len: Int, prev: Option[ScanLeaf[U]], acc: U) extends ScanTree[U] with scala.Product with Serializable

Attributes
protected[this]
case class ScanNode [U >: T](left: ScanTree[U], right: ScanTree[U]) extends ScanTree[U] with scala.Product with Serializable

Attributes
protected[this]
trait ScanTree [U >: T] extends AnyRef

Attributes
protected[this]
abstract class SeqComposite [FR, SR, R, First <: StrictSplitterCheckTask[FR, _], Second <: StrictSplitterCheckTask[SR, _]] extends Composite[FR, SR, R, First, Second]
Sequentially performs one task after another.
Sequentially performs one task after another.

Attributes
protected[this]
trait SignallingOps [PI <: DelegatedSignalling] extends AnyRef
class Slice [U >: T, This >: Repr] extends Transformer[Combiner[U, This], Slice[U, This]]

Attributes
protected[this]
class Span [U >: T, This >: Repr] extends Transformer[(Combiner[U, This], Combiner[U, This]), Span[U, This]]

Attributes
protected[this]
class SplitAt [U >: T, This >: Repr] extends Transformer[(Combiner[U, This], Combiner[U, This]), SplitAt[U, This]]

Attributes
protected[this]
trait StrictSplitterCheckTask [R, Tp] extends Task[R, Tp]

Attributes
protected
class Sum [U >: T] extends Accessor[U, Sum[U]]

Attributes
protected[this]
class Take [U >: T, This >: Repr] extends Transformer[Combiner[U, This], Take[U, This]]

Attributes
protected[this]
class TakeWhile [U >: T, This >: Repr] extends Transformer[(Combiner[U, This], Boolean), TakeWhile[U, This]]

Attributes
protected[this]
trait TaskOps [R, Tp] extends AnyRef
class ToParCollection [U >: T, That] extends Transformer[Combiner[U, That], ToParCollection[U, That]]

Attributes
protected[this]
class ToParMap [K, V, That] extends Transformer[Combiner[(K, V), That], ToParMap[K, V, That]]

Attributes
protected[this]
trait Transformer [R, Tp] extends Accessor[R, Tp]

Attributes
protected
class Zip [U >: T, S, That] extends Transformer[Combiner[(U, S), That], Zip[U, S, That]]

Attributes
protected[this]
class ZipAll [U >: T, S, That] extends Transformer[Combiner[(U, S), That], ZipAll[U, S, That]]

Attributes
protected[this]

Abstract Value Members

abstract def newCombiner: Combiner[T, Repr]

Attributes
protected[this]
Definition Classes
HasNewCombiner
abstract def seq: Sequential

Definition Classes
ParIterableLike → Parallelizable → GenTraversableOnce
abstract def size: Int

Definition Classes
GenTraversableLike → GenTraversableOnce
abstract def splitter: IterableSplitter[T]
Creates a new parallel iterator used to traverse the elements of this parallel collection.
Creates a new parallel iterator used to traverse the elements of this parallel collection. This iterator is more specific than the iterator of the returned by iterator, and augmented with additional accessor and transformer methods.
returns
a parallel iterator

Attributes
protected[scala.collection.parallel]
abstract def stringPrefix: String

Definition Classes
GenTraversableLike

Concrete Value Members

final def !=(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def ##(): Int

Definition Classes
AnyRef → Any
def ++[U >: T, That](that: GenTraversableOnce[U])(implicit bf: CanBuildFrom[Repr, U, That]): That

Definition Classes
ParIterableLike → GenTraversableLike
def /:[S](z: S)(op: (S, T) ⇒ S): S

Definition Classes
ParIterableLike → GenTraversableOnce
def :\[S](z: S)(op: (T, S) ⇒ S): S

Definition Classes
ParIterableLike → GenTraversableOnce
final def ==(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def aggregate[S](z: ⇒ S)(seqop: (S, T) ⇒ S, combop: (S, S) ⇒ S): S
Aggregates the results of applying an operator to subsequent elements.
Aggregates the results of applying an operator to subsequent elements.
This is a more general form of fold and reduce. It has similar semantics, but does not require the result to be a supertype of the element type. It traverses the elements in different partitions sequentially, using seqop to update the result, and then applies combop to results from different partitions. The implementation of this operation may operate on an arbitrary number of collection partitions, so combop may be invoked arbitrary number of times.
For example, one might want to process some elements and then produce a Set. In this case, seqop would process an element and append it to the set, while combop would concatenate two sets from different partitions together. The initial value z would be an empty set.
```
pc.aggregate(Set[Int]())(_ += process(_), _ ++ _)
```
Another example is calculating geometric mean from a collection of doubles (one would typically require big doubles for this).
S
the type of accumulated results
z
the initial value for the accumulated result of the partition - this will typically be the neutral element for the seqop operator (e.g. Nil for list concatenation or 0 for summation) and may be evaluated more than once
seqop
an operator used to accumulate results within a partition
combop
an associative operator used to combine results from different partitions

Definition Classes
ParIterableLike → GenTraversableOnce
final def asInstanceOf[T0]: T0

Definition Classes
Any
def bf2seq[S, That](bf: CanBuildFrom[Repr, S, That]): CanBuildFrom[Sequential, S, That]

Attributes
protected[this]
implicit def builder2ops[Elem, To](cb: Builder[Elem, To]): BuilderOps[Elem, To]

Attributes
protected
def canEqual(other: Any): Boolean
def clone(): AnyRef

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( ... )
def collect[S, That](pf: PartialFunction[T, S])(implicit bf: CanBuildFrom[Repr, S, That]): That

Definition Classes
ParIterableLike → GenTraversableLike
def combinerFactory[S, That](cbf: () ⇒ Combiner[S, That]): CombinerFactory[S, That]

Attributes
protected[this]
def combinerFactory: CombinerFactory[T, Repr]
Creates a combiner factory.
Creates a combiner factory. Each combiner factory instance is used once per invocation of a parallel transformer method for a single collection.
The default combiner factory creates a new combiner every time it is requested, unless the combiner is thread-safe as indicated by its canBeShared method. In this case, the method returns a factory which returns the same combiner each time. This is typically done for concurrent parallel collections, the combiners of which allow thread safe access.

Attributes
protected[this]
def copyToArray[U >: T](xs: Array[U], start: Int, len: Int): Unit

Definition Classes
ParIterableLike → GenTraversableOnce
def copyToArray[U >: T](xs: Array[U], start: Int): Unit

Definition Classes
ParIterableLike → GenTraversableOnce
def copyToArray[U >: T](xs: Array[U]): Unit

Definition Classes
ParIterableLike → GenTraversableOnce
def count(p: (T) ⇒ Boolean): Int

Definition Classes
ParIterableLike → GenTraversableOnce
def debugBuffer: ArrayBuffer[String]
implicit def delegatedSignalling2ops[PI <: DelegatedSignalling](it: PI): SignallingOps[PI]

Attributes
protected
def drop(n: Int): Repr

Definition Classes
ParIterableLike → GenTraversableLike
def dropWhile(pred: (T) ⇒ Boolean): Repr
Drops all elements in the longest prefix of elements that satisfy the predicate, and returns a collection composed of the remaining elements.
Drops all elements in the longest prefix of elements that satisfy the predicate, and returns a collection composed of the remaining elements.
This method will use indexFlag signalling capabilities. This means that splitters may set and read the indexFlag state. The index flag is initially set to maximum integer value.
pred
the predicate used to test the elements
returns
a collection composed of all the elements after the longest prefix of elements in this parallel iterable that satisfy the predicate pred

Definition Classes
ParIterableLike → GenTraversableLike
final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def equals(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def exists(p: (T) ⇒ Boolean): Boolean
Tests whether a predicate holds for some element of this parallel iterable.
Tests whether a predicate holds for some element of this parallel iterable.
This method will use abort signalling capabilities. This means that splitters may send and read abort signals.
p
a predicate used to test elements
returns
true if p holds for some element, false otherwise

Definition Classes
ParIterableLike → GenTraversableOnce
def filter(pred: (T) ⇒ Boolean): Repr

Definition Classes
ParIterableLike → GenTraversableLike
def filterNot(pred: (T) ⇒ Boolean): Repr

Definition Classes
ParIterableLike → GenTraversableLike
def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
def find(p: (T) ⇒ Boolean): Option[T]
Finds some element in the collection for which the predicate holds, if such an element exists.
Finds some element in the collection for which the predicate holds, if such an element exists. The element may not necessarily be the first such element in the iteration order.
If there are multiple elements obeying the predicate, the choice is nondeterministic.
This method will use abort signalling capabilities. This means that splitters may send and read abort signals.
p
predicate used to test the elements
returns
an option value with the element if such an element exists, or None otherwise

Definition Classes
ParIterableLike → GenTraversableOnce
def flatMap[S, That](f: (T) ⇒ GenTraversableOnce[S])(implicit bf: CanBuildFrom[Repr, S, That]): That

Definition Classes
ParIterableLike → GenTraversableLike
def fold[U >: T](z: U)(op: (U, U) ⇒ U): U
Folds the elements of this sequence using the specified associative binary operator.
Folds the elements of this sequence using the specified associative binary operator. The order in which the elements are reduced is unspecified and may be nondeterministic.
Note this method has a different signature than the foldLeft and foldRight methods of the trait Traversable. The result of folding may only be a supertype of this parallel collection's type parameter T.
U
a type parameter for the binary operator, a supertype of T.
z
a neutral element for the fold operation, it may be added to the result an arbitrary number of times, not changing the result (e.g. Nil for list concatenation, 0 for addition, or 1 for multiplication)
op
a binary operator that must be associative
returns
the result of applying fold operator op between all the elements and z

Definition Classes
ParIterableLike → GenTraversableOnce
def foldLeft[S](z: S)(op: (S, T) ⇒ S): S

Definition Classes
ParIterableLike → GenTraversableOnce
def foldRight[S](z: S)(op: (T, S) ⇒ S): S

Definition Classes
ParIterableLike → GenTraversableOnce
def forall(p: (T) ⇒ Boolean): Boolean
Tests whether a predicate holds for all elements of this parallel iterable.
Tests whether a predicate holds for all elements of this parallel iterable.
This method will use abort signalling capabilities. This means that splitters may send and read abort signals.
p
a predicate used to test elements
returns
true if p holds for all elements, false otherwise

Definition Classes
ParIterableLike → GenTraversableOnce
def foreach[U](f: (T) ⇒ U): Unit
Applies a function f to all the elements of parallel iterable in an undefined order.
Applies a function f to all the elements of parallel iterable in an undefined order.
U
the result type of the function applied to each element, which is always discarded
f
function applied to each element

Definition Classes
ParIterableLike → GenTraversableLike → GenTraversableOnce
final def getClass(): Class[_]

Definition Classes
AnyRef → Any
def groupBy[K](f: (T) ⇒ K): immutable.ParMap[K, Repr]

Definition Classes
ParIterableLike → GenTraversableLike
def hasDefiniteSize: Boolean

Definition Classes
ParIterableLike → GenTraversableOnce
def hashCode(): Int

Definition Classes
AnyRef → Any
def head: T

Definition Classes
ParIterableLike → GenTraversableLike
def headOption: Option[T]

Definition Classes
ParIterableLike → GenTraversableLike
def init: Repr

Definition Classes
ParIterableLike → GenTraversableLike
def initTaskSupport(): Unit

Attributes
protected
def isEmpty: Boolean

Definition Classes
ParIterableLike → GenTraversableOnce
final def isInstanceOf[T0]: Boolean

Definition Classes
Any
def isStrictSplitterCollection: Boolean
Denotes whether this parallel collection has strict splitters.
Denotes whether this parallel collection has strict splitters.
This is true in general, and specific collection instances may choose to override this method. Such collections will fail to execute methods which rely on splitters being strict, i.e. returning a correct value in the remaining method.
This method helps ensure that such failures occur on method invocations, rather than later on and in unpredictable ways.
final def isTraversableAgain: Boolean

Definition Classes
ParIterableLike → GenTraversableLike → GenTraversableOnce
def iterator: Splitter[T]
Creates a new split iterator used to traverse the elements of this collection.
Creates a new split iterator used to traverse the elements of this collection.
By default, this method is implemented in terms of the protected splitter method.
returns
a split iterator

Definition Classes
ParIterableLike → GenIterableLike
def last: T

Definition Classes
ParIterableLike → GenTraversableLike
def lastOption: Option[T]

Definition Classes
ParIterableLike → GenTraversableLike
def map[S, That](f: (T) ⇒ S)(implicit bf: CanBuildFrom[Repr, S, That]): That

Definition Classes
ParIterableLike → GenTraversableLike
def max[U >: T](implicit ord: Ordering[U]): T

Definition Classes
ParIterableLike → GenTraversableOnce
def maxBy[S](f: (T) ⇒ S)(implicit cmp: Ordering[S]): T

Definition Classes
ParIterableLike → GenTraversableOnce
def min[U >: T](implicit ord: Ordering[U]): T

Definition Classes
ParIterableLike → GenTraversableOnce
def minBy[S](f: (T) ⇒ S)(implicit cmp: Ordering[S]): T

Definition Classes
ParIterableLike → GenTraversableOnce
def mkString: String

Definition Classes
ParIterableLike → GenTraversableOnce
def mkString(sep: String): String

Definition Classes
ParIterableLike → GenTraversableOnce
def mkString(start: String, sep: String, end: String): String

Definition Classes
ParIterableLike → GenTraversableOnce
final def ne(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def nonEmpty: Boolean

Definition Classes
ParIterableLike → GenTraversableOnce
final def notify(): Unit

Definition Classes
AnyRef
final def notifyAll(): Unit

Definition Classes
AnyRef
def par: Repr
Returns a parallel implementation of this collection.
Returns a parallel implementation of this collection.
For most collection types, this method creates a new parallel collection by copying all the elements. For these collection, par takes linear time. Mutable collections in this category do not produce a mutable parallel collection that has the same underlying dataset, so changes in one collection will not be reflected in the other one.
Specific collections (e.g. ParArray or mutable.ParHashMap) override this default behaviour by creating a parallel collection which shares the same underlying dataset. For these collections, par takes constant or sublinear time.
All parallel collections return a reference to themselves.
returns
a parallel implementation of this collection

Definition Classes
ParIterableLike → CustomParallelizable → Parallelizable
def parCombiner: Combiner[T, Repr]
The default par implementation uses the combiner provided by this method to create a new parallel collection.
The default par implementation uses the combiner provided by this method to create a new parallel collection.
returns
a combiner for the parallel collection of type ParRepr

Attributes
protected[this]
Definition Classes
CustomParallelizable → Parallelizable
def partition(pred: (T) ⇒ Boolean): (Repr, Repr)

Definition Classes
ParIterableLike → GenTraversableLike
def product[U >: T](implicit num: Numeric[U]): U

Definition Classes
ParIterableLike → GenTraversableOnce
def reduce[U >: T](op: (U, U) ⇒ U): U
Reduces the elements of this sequence using the specified associative binary operator.
Reduces the elements of this sequence using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
Note this method has a different signature than the reduceLeft and reduceRight methods of the trait Traversable. The result of reducing may only be a supertype of this parallel collection's type parameter T.
U
A type parameter for the binary operator, a supertype of T.
op
A binary operator that must be associative.
returns
The result of applying reduce operator op between all the elements if the collection is nonempty.

Definition Classes
ParIterableLike → GenTraversableOnce
Exceptions thrown
UnsupportedOperationException if this parallel iterable is empty.
def reduceLeft[U >: T](op: (U, T) ⇒ U): U
def reduceLeftOption[U >: T](op: (U, T) ⇒ U): Option[U]

Definition Classes
ParIterableLike → GenTraversableOnce
def reduceOption[U >: T](op: (U, U) ⇒ U): Option[U]
Optionally reduces the elements of this sequence using the specified associative binary operator.
Optionally reduces the elements of this sequence using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
Note this method has a different signature than the reduceLeftOption and reduceRightOption methods of the trait Traversable. The result of reducing may only be a supertype of this parallel collection's type parameter T.
U
A type parameter for the binary operator, a supertype of T.
op
A binary operator that must be associative.
returns
An option value containing result of applying reduce operator op between all the elements if the collection is nonempty, and None otherwise.

Definition Classes
ParIterableLike → GenTraversableOnce
def reduceRight[U >: T](op: (T, U) ⇒ U): U

Definition Classes
ParIterableLike → GenTraversableOnce
def reduceRightOption[U >: T](op: (T, U) ⇒ U): Option[U]

Definition Classes
ParIterableLike → GenTraversableOnce
def repr: Repr

Definition Classes
ParIterableLike → GenTraversableLike
def reuse[S, That](oldc: Option[Combiner[S, That]], newc: Combiner[S, That]): Combiner[S, That]
Optionally reuses an existing combiner for better performance.
Optionally reuses an existing combiner for better performance. By default it doesn't - subclasses may override this behaviour. The provided combiner oldc that can potentially be reused will be either some combiner from the previous computational task, or None if there was no previous phase (in which case this method must return newc).
oldc
The combiner that is the result of the previous task, or None if there was no previous task.
newc
The new, empty combiner that can be used.
returns
Either newc or oldc.

Attributes
protected
def sameElements[U >: T](that: GenIterable[U]): Boolean

Definition Classes
ParIterableLike → GenIterableLike
def scan(z: T)(op: (T, T) ⇒ T): ParIterable[T]
[use case] Computes a prefix scan of the elements of the collection.
[use case]
Computes a prefix scan of the elements of the collection.
Note: The neutral element z may be applied more than once.
z
neutral element for the operator op
op
the associative operator for the scan
returns
a new parallel iterable containing the prefix scan of the elements in this parallel iterable

Definition Classes
ParIterableLike → GenTraversableLike
Full Signature
def scan[U >: T, That](z: U)(op: (U, U) ⇒ U)(implicit bf: CanBuildFrom[Repr, U, That]): That
def scanBlockSize: Int

Attributes
protected[this]
def scanLeft[S, That](z: S)(op: (S, T) ⇒ S)(implicit bf: CanBuildFrom[Repr, S, That]): That

Definition Classes
ParIterableLike → GenTraversableLike
def scanRight[S, That](z: S)(op: (T, S) ⇒ S)(implicit bf: CanBuildFrom[Repr, S, That]): That

Definition Classes
ParIterableLike → GenTraversableLike
def sequentially[S, That <: Parallel](b: (Sequential) ⇒ Sequential): Repr

Attributes
protected[this]
def sizeHintIfCheap: Int

Attributes
protected[scala.collection]
Definition Classes
GenTraversableOnce
def slice(unc_from: Int, unc_until: Int): Repr

Definition Classes
ParIterableLike → GenTraversableLike
def span(pred: (T) ⇒ Boolean): (Repr, Repr)
Splits this parallel iterable into a prefix/suffix pair according to a predicate.
Splits this parallel iterable into a prefix/suffix pair according to a predicate.
This method will use indexFlag signalling capabilities. This means that splitters may set and read the indexFlag state. The index flag is initially set to maximum integer value.
pred
the predicate used to test the elements
returns
a pair consisting of the longest prefix of the collection for which all the elements satisfy pred, and the rest of the collection

Definition Classes
ParIterableLike → GenTraversableLike
def splitAt(n: Int): (Repr, Repr)

Definition Classes
ParIterableLike → GenTraversableLike
def sum[U >: T](implicit num: Numeric[U]): U

Definition Classes
ParIterableLike → GenTraversableOnce
final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
def tail: Repr

Definition Classes
ParIterableLike → GenTraversableLike
def take(n: Int): Repr

Definition Classes
ParIterableLike → GenTraversableLike
def takeWhile(pred: (T) ⇒ Boolean): Repr
Takes the longest prefix of elements that satisfy the predicate.
Takes the longest prefix of elements that satisfy the predicate.
This method will use indexFlag signalling capabilities. This means that splitters may set and read the indexFlag state. The index flag is initially set to maximum integer value.
pred
the predicate used to test the elements
returns
the longest prefix of this parallel iterable of elements that satisfy the predicate pred

Definition Classes
ParIterableLike → GenTraversableLike
implicit def task2ops[R, Tp](tsk: SSCTask[R, Tp]): TaskOps[R, Tp]

Attributes
protected
def tasksupport: TaskSupport
The task support object which is responsible for scheduling and load-balancing tasks to processors.
The task support object which is responsible for scheduling and load-balancing tasks to processors.

See also
scala.collection.parallel.TaskSupport
def tasksupport_=(ts: TaskSupport): Unit
Changes the task support object which is responsible for scheduling and load-balancing tasks to processors.
Changes the task support object which is responsible for scheduling and load-balancing tasks to processors.
A task support object can be changed in a parallel collection after it has been created, but only during a quiescent period, i.e. while there are no concurrent invocations to parallel collection methods.
Here is a way to change the task support of a parallel collection:
```
import scala.collection.parallel._
val pc = mutable.ParArray(1, 2, 3)
pc.tasksupport = new ForkJoinTaskSupport(
  new java.util.concurrent.ForkJoinPool(2))
```
See also
scala.collection.parallel.TaskSupport
def to[Col[_]](implicit cbf: CanBuildFrom[Nothing, T, Col[T]]): Col[T]

Definition Classes
ParIterableLike → GenTraversableOnce
def toArray[U >: T](implicit arg0: ClassTag[U]): Array[U]

Definition Classes
ParIterableLike → GenTraversableOnce
def toBuffer[U >: T]: Buffer[U]

Definition Classes
ParIterableLike → GenTraversableOnce
def toIndexedSeq: immutable.IndexedSeq[T]

Definition Classes
ParIterableLike → GenTraversableOnce
def toIterable: ParIterable[T]

Definition Classes
ParIterableLike → GenTraversableOnce
def toIterator: scala.Iterator[T]

Definition Classes
ParIterableLike → GenTraversableOnce
def toList: List[T]

Definition Classes
ParIterableLike → GenTraversableOnce
def toMap[K, V](implicit ev: <:<[T, (K, V)]): immutable.ParMap[K, V]

Definition Classes
ParIterableLike → GenTraversableOnce
def toParCollection[U >: T, That](cbf: () ⇒ Combiner[U, That]): That

Attributes
protected
def toParMap[K, V, That](cbf: () ⇒ Combiner[(K, V), That])(implicit ev: <:<[T, (K, V)]): That

Attributes
protected
def toSeq: ParSeq[T]

Definition Classes
ParIterableLike → GenTraversableOnce
def toSet[U >: T]: immutable.ParSet[U]

Definition Classes
ParIterableLike → GenTraversableOnce
def toStream: Stream[T]

Definition Classes
ParIterableLike → GenTraversableOnce
def toString(): String

Definition Classes
ParIterableLike → AnyRef → Any
def toTraversable: GenTraversable[T]

Definition Classes
ParIterableLike → GenTraversableOnce
def toVector: Vector[T]

Definition Classes
ParIterableLike → GenTraversableOnce
final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
def withFilter(pred: (T) ⇒ Boolean): Repr
def wrap[R](body: ⇒ R): NonDivisible[R]

Attributes
protected
def zip[U >: T, S, That](that: GenIterable[S])(implicit bf: CanBuildFrom[Repr, (U, S), That]): That

Definition Classes
ParIterableLike → GenIterableLike
def zipAll[S, U >: T, That](that: GenIterable[S], thisElem: U, thatElem: S)(implicit bf: CanBuildFrom[Repr, (U, S), That]): That

Definition Classes
ParIterableLike → GenIterableLike
def zipWithIndex[U >: T, That](implicit bf: CanBuildFrom[Repr, (U, Int), That]): That

Definition Classes
ParIterableLike → GenIterableLike

Packages

ParIterableLike

trait ParIterableLike[+T, +Repr <: ParIterable[T], +Sequential <: scala.Iterable[T] with IterableLike[T, Sequential]] extends GenIterableLike[T, Repr] with CustomParallelizable[T, Repr] with Parallel with HasNewCombiner[T, Repr]

Type Members

Abstract Value Members

Concrete Value Members

def scan[U >: T, That](z: U)(op: (U, U) ⇒ U)(implicit bf: CanBuildFrom[Repr, U, That]): That

Inherited from HasNewCombiner[T, Repr]

Inherited from Parallel

Inherited from CustomParallelizable[T, Repr]

Inherited from Parallelizable[T, Repr]

Inherited from GenIterableLike[T, Repr]

Inherited from GenTraversableLike[T, Repr]

Inherited from GenTraversableOnce[T]

Inherited from AnyRef

Inherited from Any

Ungrouped

Packages

ParIterableLike 

trait ParIterableLike[+T, +Repr <: ParIterable[T], +Sequential <: scala.Iterable[T] with IterableLike[T, Sequential]] extends GenIterableLike[T, Repr] with CustomParallelizable[T, Repr] with Parallel with HasNewCombiner[T, Repr]

Type Members

Abstract Value Members

Concrete Value Members

def scan[U >: T, That](z: U)(op: (U, U) ⇒ U)(implicit bf: CanBuildFrom[Repr, U, That]): That

Inherited from HasNewCombiner[T, Repr]

Inherited from Parallel

Inherited from CustomParallelizable[T, Repr]

Inherited from Parallelizable[T, Repr]

Inherited from GenIterableLike[T, Repr]

Inherited from GenTraversableLike[T, Repr]

Inherited from GenTraversableOnce[T]

Inherited from AnyRef

Inherited from Any

Ungrouped

ParIterableLike