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scala.collection.parallel

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]
Source
ParIterableLike.scala
Linear Supertypes
Ordering
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Inherited
  1. ParIterableLike
  2. HasNewCombiner
  3. Parallel
  4. CustomParallelizable
  5. GenIterableLike
  6. GenTraversableLike
  7. Parallelizable
  8. GenTraversableOnce
  9. AnyRef
  10. Any
Implicitly
  1. by CollectionsHaveToParArray
  2. by any2stringadd
  3. by StringFormat
  4. by Ensuring
  5. by ArrowAssoc
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Visibility
  1. Public
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Type Members

  1. 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
  2. class Aggregate[S] extends Accessor[S, Aggregate[S]]
    Attributes
    protected[this]
  3. trait BuilderOps[Elem, To] extends AnyRef
  4. class Collect[S, That] extends Transformer[Combiner[S, That], Collect[S, That]]
    Attributes
    protected[this]
  5. abstract class Composite[FR, SR, R, First <: StrictSplitterCheckTask[FR, _], Second <: StrictSplitterCheckTask[SR, _]] extends NonDivisibleTask[R, Composite[FR, SR, R, First, Second]]
    Attributes
    protected[this]
  6. class Copy[U >: T, That] extends Transformer[Combiner[U, That], Copy[U, That]]
    Attributes
    protected
  7. class CopyToArray[U >: T, This >: Repr] extends Accessor[Unit, CopyToArray[U, This]]
    Attributes
    protected[this]
  8. class Count extends Accessor[Int, Count]
    Attributes
    protected[this]
  9. class CreateScanTree[U >: T] extends Transformer[ScanTree[U], CreateScanTree[U]]
    Attributes
    protected[this]
  10. class Drop[U >: T, This >: Repr] extends Transformer[Combiner[U, This], Drop[U, This]]
    Attributes
    protected[this]
  11. class Exists extends Accessor[Boolean, Exists]
    Attributes
    protected[this]
  12. class Filter[U >: T, This >: Repr] extends Transformer[Combiner[U, This], Filter[U, This]]
    Attributes
    protected[this]
  13. class FilterNot[U >: T, This >: Repr] extends Transformer[Combiner[U, This], FilterNot[U, This]]
    Attributes
    protected[this]
  14. class Find[U >: T] extends Accessor[Option[U], Find[U]]
    Attributes
    protected[this]
  15. class FlatMap[S, That] extends Transformer[Combiner[S, That], FlatMap[S, That]]
    Attributes
    protected[this]
  16. class Fold[U >: T] extends Accessor[U, Fold[U]]
    Attributes
    protected[this]
  17. class Forall extends Accessor[Boolean, Forall]
    Attributes
    protected[this]
  18. class Foreach[S] extends Accessor[Unit, Foreach[S]]
    Attributes
    protected[this]
  19. class FromScanTree[U >: T, That] extends StrictSplitterCheckTask[Combiner[U, That], FromScanTree[U, That]]
    Attributes
    protected[this]
  20. class GroupBy[K, U >: T] extends Transformer[HashMapCombiner[K, U], GroupBy[K, U]]
    Attributes
    protected[this]
  21. class Map[S, That] extends Transformer[Combiner[S, That], Map[S, That]]
    Attributes
    protected[this]
  22. class Max[U >: T] extends Accessor[Option[U], Max[U]]
    Attributes
    protected[this]
  23. class Min[U >: T] extends Accessor[Option[U], Min[U]]
    Attributes
    protected[this]
  24. trait NonDivisible[R] extends NonDivisibleTask[R, NonDivisible[R]]
    Attributes
    protected[this]
  25. trait NonDivisibleTask[R, Tp] extends StrictSplitterCheckTask[R, Tp]
    Attributes
    protected[this]
  26. 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]
  27. class Partition[U >: T, This >: Repr] extends Transformer[(Combiner[U, This], Combiner[U, This]), Partition[U, This]]
    Attributes
    protected[this]
  28. class Product[U >: T] extends Accessor[U, Product[U]]
    Attributes
    protected[this]
  29. class Reduce[U >: T] extends Accessor[Option[U], Reduce[U]]
    Attributes
    protected[this]
  30. abstract class ResultMapping[R, Tp, R1] extends NonDivisibleTask[R1, ResultMapping[R, Tp, R1]]
    Attributes
    protected[this]
  31. type SSCTask[R, Tp] = StrictSplitterCheckTask[R, Tp]
  32. 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]
  33. case class ScanNode[U >: T](left: ScanTree[U], right: ScanTree[U]) extends ScanTree[U] with scala.Product with Serializable
    Attributes
    protected[this]
  34. trait ScanTree[U >: T] extends AnyRef
    Attributes
    protected[this]
  35. 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]
  36. trait SignallingOps[PI <: DelegatedSignalling] extends AnyRef
  37. class Slice[U >: T, This >: Repr] extends Transformer[Combiner[U, This], Slice[U, This]]
    Attributes
    protected[this]
  38. class Span[U >: T, This >: Repr] extends Transformer[(Combiner[U, This], Combiner[U, This]), Span[U, This]]
    Attributes
    protected[this]
  39. class SplitAt[U >: T, This >: Repr] extends Transformer[(Combiner[U, This], Combiner[U, This]), SplitAt[U, This]]
    Attributes
    protected[this]
  40. trait StrictSplitterCheckTask[R, Tp] extends Task[R, Tp]
    Attributes
    protected
  41. class Sum[U >: T] extends Accessor[U, Sum[U]]
    Attributes
    protected[this]
  42. class Take[U >: T, This >: Repr] extends Transformer[Combiner[U, This], Take[U, This]]
    Attributes
    protected[this]
  43. class TakeWhile[U >: T, This >: Repr] extends Transformer[(Combiner[U, This], Boolean), TakeWhile[U, This]]
    Attributes
    protected[this]
  44. trait TaskOps[R, Tp] extends AnyRef
  45. class ToParCollection[U >: T, That] extends Transformer[Combiner[U, That], ToParCollection[U, That]]
    Attributes
    protected[this]
  46. class ToParMap[K, V, That] extends Transformer[Combiner[(K, V), That], ToParMap[K, V, That]]
    Attributes
    protected[this]
  47. trait Transformer[R, Tp] extends Accessor[R, Tp]
    Attributes
    protected
  48. class Zip[U >: T, S, That] extends Transformer[Combiner[(U, S), That], Zip[U, S, That]]
    Attributes
    protected[this]
  49. class ZipAll[U >: T, S, That] extends Transformer[Combiner[(U, S), That], ZipAll[U, S, That]]
    Attributes
    protected[this]

Abstract Value Members

  1. abstract def newCombiner: Combiner[T, Repr]
    Attributes
    protected[this]
    Definition Classes
    HasNewCombiner
  2. abstract def seq: Sequential
  3. abstract def size: Int

    The size of this general collection.

    The size of this general collection.

    Note: will not terminate for infinite-sized collections.

    returns

    the number of elements in this general collection.

    Definition Classes
    GenTraversableLikeGenTraversableOnce
  4. 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[parallel]
  5. abstract def stringPrefix: String

    Defines the prefix of this object's toString representation.

    Defines the prefix of this object's toString representation.

    returns

    a string representation which starts the result of toString applied to this general collection. By default the string prefix is the simple name of the collection class general collection.

    Definition Classes
    GenTraversableLike

Concrete Value Members

  1. final def !=(arg0: Any): Boolean

    Test two objects for inequality.

    Test two objects for inequality.

    returns

    true if !(this == that), false otherwise.

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

    Equivalent to x.hashCode except for boxed numeric types and null.

    Equivalent to x.hashCode except for boxed numeric types and null. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For null returns a hashcode where null.hashCode throws a NullPointerException.

    returns

    a hash value consistent with ==

    Definition Classes
    AnyRef → Any
  3. def +(other: String): String
    Implicit
    This member is added by an implicit conversion from ParIterableLike[T, Repr, Sequential] to any2stringadd[ParIterableLike[T, Repr, Sequential]] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ++[U >: T, That](that: GenTraversableOnce[U])(implicit bf: CanBuildFrom[Repr, U, That]): That

    Returns a new parallel iterable containing the elements from the left hand operand followed by the elements from the right hand operand.

    Returns a new parallel iterable containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the parallel iterable is the most specific superclass encompassing the element types of the two operands.

    That

    the class of the returned collection. Where possible, That is the same class as the current collection class Repr, but this depends on the element type B being admissible for that class, which means that an implicit instance of type CanBuildFrom[Repr, B, That] is found.

    that

    the traversable to append.

    bf

    an implicit value of class CanBuildFrom which determines the result class That from the current representation type Repr and the new element type B.

    returns

    a new collection of type That which contains all elements of this parallel iterable followed by all elements of that.

    Definition Classes
    ParIterableLikeGenTraversableLike
  5. def ->[B](y: B): (ParIterableLike[T, Repr, Sequential], B)
    Implicit
    This member is added by an implicit conversion from ParIterableLike[T, Repr, Sequential] to ArrowAssoc[ParIterableLike[T, Repr, Sequential]] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  6. final def ==(arg0: Any): Boolean

    The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

    The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    Definition Classes
    AnyRef → Any
  7. 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
    ParIterableLikeGenTraversableOnce
  8. final def asInstanceOf[T0]: T0

    Cast the receiver object to be of type T0.

    Cast the receiver object to be of type T0.

    Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression 1.asInstanceOf[String] will throw a ClassCastException at runtime, while the expression List(1).asInstanceOf[List[String]] will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.

    returns

    the receiver object.

    Definition Classes
    Any
    Exceptions thrown

    ClassCastException if the receiver object is not an instance of the erasure of type T0.

  9. def bf2seq[S, That](bf: CanBuildFrom[Repr, S, That]): CanBuildFrom[Sequential, S, That]
    Attributes
    protected[this]
  10. implicit def builder2ops[Elem, To](cb: Builder[Elem, To]): BuilderOps[Elem, To]
    Attributes
    protected
  11. def canEqual(other: Any): Boolean
  12. def clone(): AnyRef

    Create a copy of the receiver object.

    Create a copy of the receiver object.

    The default implementation of the clone method is platform dependent.

    returns

    a copy of the receiver object.

    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native()
    Note

    not specified by SLS as a member of AnyRef

  13. def collect[B](pf: PartialFunction[A, B]): ParIterable[B]

    [use case] Builds a new collection by applying a partial function to all elements of this parallel iterable on which the function is defined.

    [use case]

    Builds a new collection by applying a partial function to all elements of this parallel iterable on which the function is defined.

    B

    the element type of the returned collection.

    pf

    the partial function which filters and maps the parallel iterable.

    returns

    a new parallel iterable resulting from applying the given partial function pf to each element on which it is defined and collecting the results. The order of the elements is preserved.

    Definition Classes
    ParIterableLikeGenTraversableLike
    Full Signature

    def collect[S, That](pf: PartialFunction[T, S])(implicit bf: CanBuildFrom[Repr, S, That]): That

  14. def combinerFactory[S, That](cbf: () ⇒ Combiner[S, That]): CombinerFactory[S, That]
    Attributes
    protected[this]
  15. 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]
  16. def copyToArray(xs: Array[A], start: Int, len: Int): Unit

    [use case] Copies the elements of this parallel iterable to an array.

    [use case]

    Copies the elements of this parallel iterable to an array. Fills the given array xs with at most len elements of this parallel iterable, starting at position start. Copying will stop once either the end of the current parallel iterable is reached, or the end of the target array is reached, or len elements have been copied.

    Note: will not terminate for infinite-sized collections.

    xs

    the array to fill.

    start

    the starting index.

    len

    the maximal number of elements to copy.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

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

  17. def copyToArray(xs: Array[A], start: Int): Unit

    [use case] Copies the elements of this parallel iterable to an array.

    [use case]

    Copies the elements of this parallel iterable to an array. Fills the given array xs with values of this parallel iterable, beginning at index start. Copying will stop once either the end of the current parallel iterable is reached, or the end of the target array is reached.

    Note: will not terminate for infinite-sized collections.

    xs

    the array to fill.

    start

    the starting index.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

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

  18. def copyToArray(xs: Array[A]): Unit

    [use case] Copies the elements of this parallel iterable to an array.

    [use case]

    Copies the elements of this parallel iterable to an array. Fills the given array xs with values of this parallel iterable. Copying will stop once either the end of the current parallel iterable is reached, or the end of the target array is reached.

    Note: will not terminate for infinite-sized collections.

    xs

    the array to fill.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def copyToArray[U >: T](xs: Array[U]): Unit

  19. def count(p: (T) ⇒ Boolean): Int

    Counts the number of elements in the parallel iterable which satisfy a predicate.

    Counts the number of elements in the parallel iterable which satisfy a predicate.

    p

    the predicate used to test elements.

    returns

    the number of elements satisfying the predicate p.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  20. def debugBuffer: ArrayBuffer[String]
  21. implicit def delegatedSignalling2ops[PI <: DelegatedSignalling](it: PI): SignallingOps[PI]
    Attributes
    protected
  22. def drop(n: Int): Repr

    Selects all elements except first n ones.

    Selects all elements except first n ones.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    n

    the number of elements to drop from this parallel iterable.

    returns

    a parallel iterable consisting of all elements of this parallel iterable except the first n ones, or else the empty parallel iterable, if this parallel iterable has less than n elements. If n is negative, don't drop any elements.

    Definition Classes
    ParIterableLikeGenTraversableLike
  23. 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
    ParIterableLikeGenTraversableLike
  24. def ensuring(cond: (ParIterableLike[T, Repr, Sequential]) ⇒ Boolean, msg: ⇒ Any): ParIterableLike[T, Repr, Sequential]
    Implicit
    This member is added by an implicit conversion from ParIterableLike[T, Repr, Sequential] to Ensuring[ParIterableLike[T, Repr, Sequential]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  25. def ensuring(cond: (ParIterableLike[T, Repr, Sequential]) ⇒ Boolean): ParIterableLike[T, Repr, Sequential]
    Implicit
    This member is added by an implicit conversion from ParIterableLike[T, Repr, Sequential] to Ensuring[ParIterableLike[T, Repr, Sequential]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  26. def ensuring(cond: Boolean, msg: ⇒ Any): ParIterableLike[T, Repr, Sequential]
    Implicit
    This member is added by an implicit conversion from ParIterableLike[T, Repr, Sequential] to Ensuring[ParIterableLike[T, Repr, Sequential]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  27. def ensuring(cond: Boolean): ParIterableLike[T, Repr, Sequential]
    Implicit
    This member is added by an implicit conversion from ParIterableLike[T, Repr, Sequential] to Ensuring[ParIterableLike[T, Repr, Sequential]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  28. final def eq(arg0: AnyRef): Boolean

    Tests whether the argument (that) is a reference to the receiver object (this).

    Tests whether the argument (that) is a reference to the receiver object (this).

    The eq method implements an equivalence relation on non-null instances of AnyRef, and has three additional properties:

    • It is consistent: for any non-null instances x and y of type AnyRef, multiple invocations of x.eq(y) consistently returns true or consistently returns false.
    • For any non-null instance x of type AnyRef, x.eq(null) and null.eq(x) returns false.
    • null.eq(null) returns true.

    When overriding the equals or hashCode methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).

    returns

    true if the argument is a reference to the receiver object; false otherwise.

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

    The equality method for reference types.

    The equality method for reference types. Default implementation delegates to eq.

    See also equals in scala.Any.

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    Definition Classes
    AnyRef → Any
  30. 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
    ParIterableLikeGenTraversableOnce
  31. def filter(pred: (T) ⇒ Boolean): Repr

    Selects all elements of this parallel iterable which satisfy a predicate.

    Selects all elements of this parallel iterable which satisfy a predicate.

    pred

    the predicate used to test elements.

    returns

    a new parallel iterable consisting of all elements of this parallel iterable that satisfy the given predicate p. Their order may not be preserved.

    Definition Classes
    ParIterableLikeGenTraversableLike
  32. def filterNot(pred: (T) ⇒ Boolean): Repr

    Selects all elements of this parallel iterable which do not satisfy a predicate.

    Selects all elements of this parallel iterable which do not satisfy a predicate.

    pred

    the predicate used to test elements.

    returns

    a new parallel iterable consisting of all elements of this parallel iterable that do not satisfy the given predicate p. Their order may not be preserved.

    Definition Classes
    ParIterableLikeGenTraversableLike
  33. def finalize(): Unit

    Called by the garbage collector on the receiver object when there are no more references to the object.

    Called by the garbage collector on the receiver object when there are no more references to the object.

    The details of when and if the finalize method is invoked, as well as the interaction between finalize and non-local returns and exceptions, are all platform dependent.

    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
    Note

    not specified by SLS as a member of AnyRef

  34. 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
    ParIterableLikeGenTraversableOnce
  35. def flatMap[B](f: (A) ⇒ GenTraversableOnce[B]): ParIterable[B]

    [use case] Builds a new collection by applying a function to all elements of this parallel iterable and using the elements of the resulting collections.

    [use case]

    Builds a new collection by applying a function to all elements of this parallel iterable and using the elements of the resulting collections.

    For example:

    def getWords(lines: Seq[String]): Seq[String] = lines flatMap (line => line split "\\W+")

    The type of the resulting collection is guided by the static type of parallel iterable. This might cause unexpected results sometimes. For example:

    // lettersOf will return a Seq[Char] of likely repeated letters, instead of a Set
    def lettersOf(words: Seq[String]) = words flatMap (word => word.toSet)
    
    // lettersOf will return a Set[Char], not a Seq
    def lettersOf(words: Seq[String]) = words.toSet flatMap (word => word.toSeq)
    
    // xs will be an Iterable[Int]
    val xs = Map("a" -> List(11,111), "b" -> List(22,222)).flatMap(_._2)
    
    // ys will be a Map[Int, Int]
    val ys = Map("a" -> List(1 -> 11,1 -> 111), "b" -> List(2 -> 22,2 -> 222)).flatMap(_._2)
    B

    the element type of the returned collection.

    f

    the function to apply to each element.

    returns

    a new parallel iterable resulting from applying the given collection-valued function f to each element of this parallel iterable and concatenating the results.

    Definition Classes
    ParIterableLikeGenTraversableLike
    Full Signature

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

  36. 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
    ParIterableLikeGenTraversableOnce
  37. def foldLeft[S](z: S)(op: (S, T) ⇒ S): S

    Applies a binary operator to a start value and all elements of this parallel iterable, going left to right.

    Applies a binary operator to a start value and all elements of this parallel iterable, going left to right.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    z

    the start value.

    op

    the binary operator.

    returns

    the result of inserting op between consecutive elements of this parallel iterable, going left to right with the start value z on the left:

    op(...op(z, x_1), x_2, ..., x_n)

    where x1, ..., xn are the elements of this parallel iterable. Returns z if this parallel iterable is empty.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  38. def foldRight[S](z: S)(op: (T, S) ⇒ S): S

    Applies a binary operator to all elements of this parallel iterable and a start value, going right to left.

    Applies a binary operator to all elements of this parallel iterable and a start value, going right to left.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    z

    the start value.

    op

    the binary operator.

    returns

    the result of inserting op between consecutive elements of this parallel iterable, going right to left with the start value z on the right:

    op(x_1, op(x_2, ... op(x_n, z)...))

    where x1, ..., xn are the elements of this parallel iterable. Returns z if this parallel iterable is empty.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  39. 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
    ParIterableLikeGenTraversableOnce
  40. 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
    ParIterableLikeGenTraversableLikeGenTraversableOnce
  41. final def getClass(): Class[_]

    Returns the runtime class representation of the object.

    Returns the runtime class representation of the object.

    returns

    a class object corresponding to the runtime type of the receiver.

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

    Partitions this parallel iterable into a map of parallel iterables according to some discriminator function.

    Partitions this parallel iterable into a map of parallel iterables according to some discriminator function.

    Note: this method is not re-implemented by views. This means when applied to a view it will always force the view and return a new parallel iterable.

    K

    the type of keys returned by the discriminator function.

    f

    the discriminator function.

    returns

    A map from keys to parallel iterables such that the following invariant holds:

    (xs groupBy f)(k) = xs filter (x => f(x) == k)

    That is, every key k is bound to a parallel iterable of those elements x for which f(x) equals k.

    Definition Classes
    ParIterableLikeGenTraversableLike
  43. def hasDefiniteSize: Boolean

    Tests whether this parallel iterable is known to have a finite size.

    Tests whether this parallel iterable is known to have a finite size. All strict collections are known to have finite size. For a non-strict collection such as Stream, the predicate returns true if all elements have been computed. It returns false if the stream is not yet evaluated to the end. Non-empty Iterators usually return false even if they were created from a collection with a known finite size.

    Note: many collection methods will not work on collections of infinite sizes. The typical failure mode is an infinite loop. These methods always attempt a traversal without checking first that hasDefiniteSize returns true. However, checking hasDefiniteSize can provide an assurance that size is well-defined and non-termination is not a concern.

    returns

    true if this collection is known to have finite size, false otherwise.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  44. def hashCode(): Int

    The hashCode method for reference types.

    The hashCode method for reference types. See hashCode in scala.Any.

    returns

    the hash code value for this object.

    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  45. def head: T

    Selects the first element of this parallel iterable.

    Selects the first element of this parallel iterable.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

    the first element of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableLike
    Exceptions thrown

    NoSuchElementException if the parallel iterable is empty.

  46. def headOption: Option[T]

    Optionally selects the first element.

    Optionally selects the first element.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

    the first element of this parallel iterable if it is nonempty, None if it is empty.

    Definition Classes
    ParIterableLikeGenTraversableLike
  47. def init: Repr

    Selects all elements except the last.

    Selects all elements except the last.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

    a parallel iterable consisting of all elements of this parallel iterable except the last one.

    Definition Classes
    ParIterableLikeGenTraversableLike
    Exceptions thrown

    UnsupportedOperationException if the parallel iterable is empty.

  48. def initTaskSupport(): Unit
    Attributes
    protected
  49. def isEmpty: Boolean

    Tests whether the parallel iterable is empty.

    Tests whether the parallel iterable is empty.

    Note: Implementations in subclasses that are not repeatedly traversable must take care not to consume any elements when isEmpty is called.

    returns

    true if the parallel iterable contains no elements, false otherwise.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  50. final def isInstanceOf[T0]: Boolean

    Test whether the dynamic type of the receiver object is T0.

    Test whether the dynamic type of the receiver object is T0.

    Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression 1.isInstanceOf[String] will return false, while the expression List(1).isInstanceOf[List[String]] will return true. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.

    returns

    true if the receiver object is an instance of erasure of type T0; false otherwise.

    Definition Classes
    Any
  51. 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.

  52. final def isTraversableAgain: Boolean

    Tests whether this parallel iterable can be repeatedly traversed.

    Tests whether this parallel iterable can be repeatedly traversed.

    returns

    true

    Definition Classes
    ParIterableLikeGenTraversableLikeGenTraversableOnce
  53. 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
    ParIterableLikeGenIterableLike
  54. def last: T

    Selects the last element.

    Selects the last element.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

    The last element of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableLike
    Exceptions thrown

    NoSuchElementException If the parallel iterable is empty.

  55. def lastOption: Option[T]

    Optionally selects the last element.

    Optionally selects the last element.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

    the last element of this parallel iterable$ if it is nonempty, None if it is empty.

    Definition Classes
    ParIterableLikeGenTraversableLike
  56. def map[B](f: (A) ⇒ B): ParIterable[B]

    [use case] Builds a new collection by applying a function to all elements of this parallel iterable.

    [use case]

    Builds a new collection by applying a function to all elements of this parallel iterable.

    B

    the element type of the returned collection.

    f

    the function to apply to each element.

    returns

    a new parallel iterable resulting from applying the given function f to each element of this parallel iterable and collecting the results.

    Definition Classes
    ParIterableLikeGenTraversableLike
    Full Signature

    def map[S, That](f: (T) ⇒ S)(implicit bf: CanBuildFrom[Repr, S, That]): That

  57. def max: A

    [use case] Finds the largest element.

    [use case]

    Finds the largest element.

    returns

    the largest element of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def max[U >: T](implicit ord: Ordering[U]): T

    Exceptions thrown

    UnsupportedOperationException if this parallel iterable is empty.

  58. def maxBy[B](f: (A) ⇒ B): A

    [use case] Finds the first element which yields the largest value measured by function f.

    [use case]

    Finds the first element which yields the largest value measured by function f.

    B

    The result type of the function f.

    f

    The measuring function.

    returns

    the first element of this parallel iterable with the largest value measured by function f.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def maxBy[S](f: (T) ⇒ S)(implicit cmp: Ordering[S]): T

    Exceptions thrown

    UnsupportedOperationException if this parallel iterable is empty.

  59. def min: A

    [use case] Finds the smallest element.

    [use case]

    Finds the smallest element.

    returns

    the smallest element of this parallel iterable

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def min[U >: T](implicit ord: Ordering[U]): T

    Exceptions thrown

    UnsupportedOperationException if this parallel iterable is empty.

  60. def minBy[B](f: (A) ⇒ B): A

    [use case] Finds the first element which yields the smallest value measured by function f.

    [use case]

    Finds the first element which yields the smallest value measured by function f.

    B

    The result type of the function f.

    f

    The measuring function.

    returns

    the first element of this parallel iterable with the smallest value measured by function f.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def minBy[S](f: (T) ⇒ S)(implicit cmp: Ordering[S]): T

    Exceptions thrown

    UnsupportedOperationException if this parallel iterable is empty.

  61. def mkString: String

    Displays all elements of this parallel iterable in a string.

    Displays all elements of this parallel iterable in a string.

    returns

    a string representation of this parallel iterable. In the resulting string the string representations (w.r.t. the method toString) of all elements of this parallel iterable follow each other without any separator string.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  62. def mkString(sep: String): String

    Displays all elements of this parallel iterable in a string using a separator string.

    Displays all elements of this parallel iterable in a string using a separator string.

    sep

    the separator string.

    returns

    a string representation of this parallel iterable. In the resulting string the string representations (w.r.t. the method toString) of all elements of this parallel iterable are separated by the string sep.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Example:
    1. List(1, 2, 3).mkString("|") = "1|2|3"

  63. def mkString(start: String, sep: String, end: String): String

    Displays all elements of this parallel iterable in a string using start, end, and separator strings.

    Displays all elements of this parallel iterable in a string using start, end, and separator strings.

    start

    the starting string.

    sep

    the separator string.

    end

    the ending string.

    returns

    a string representation of this parallel iterable. The resulting string begins with the string start and ends with the string end. Inside, the string representations (w.r.t. the method toString) of all elements of this parallel iterable are separated by the string sep.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Example:
    1. List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"

  64. final def ne(arg0: AnyRef): Boolean

    Equivalent to !(this eq that).

    Equivalent to !(this eq that).

    returns

    true if the argument is not a reference to the receiver object; false otherwise.

    Definition Classes
    AnyRef
  65. def nonEmpty: Boolean

    Tests whether the parallel iterable is not empty.

    Tests whether the parallel iterable is not empty.

    returns

    true if the parallel iterable contains at least one element, false otherwise.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  66. final def notify(): Unit

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Definition Classes
    AnyRef
    Annotations
    @native()
    Note

    not specified by SLS as a member of AnyRef

  67. final def notifyAll(): Unit

    Wakes up all threads that are waiting on the receiver object's monitor.

    Wakes up all threads that are waiting on the receiver object's monitor.

    Definition Classes
    AnyRef
    Annotations
    @native()
    Note

    not specified by SLS as a member of AnyRef

  68. 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
    ParIterableLikeCustomParallelizableParallelizable
  69. 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
    CustomParallelizableParallelizable
  70. def partition(pred: (T) ⇒ Boolean): (Repr, Repr)

    Partitions this parallel iterable in two parallel iterables according to a predicate.

    Partitions this parallel iterable in two parallel iterables according to a predicate.

    pred

    the predicate on which to partition.

    returns

    a pair of parallel iterables: the first parallel iterable consists of all elements that satisfy the predicate p and the second parallel iterable consists of all elements that don't. The relative order of the elements in the resulting parallel iterables may not be preserved.

    Definition Classes
    ParIterableLikeGenTraversableLike
  71. def product: A

    [use case] Multiplies up the elements of this collection.

    [use case]

    Multiplies up the elements of this collection.

    returns

    the product of all elements in this parallel iterable of numbers of type Int. Instead of Int, any other type T with an implicit Numeric[T] implementation can be used as element type of the parallel iterable and as result type of product. Examples of such types are: Long, Float, Double, BigInt.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def product[U >: T](implicit num: Numeric[U]): U

  72. 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
    ParIterableLikeGenTraversableOnce
    Exceptions thrown

    UnsupportedOperationException if this parallel iterable is empty.

  73. def reduceLeft[U >: T](op: (U, T) ⇒ U): U
  74. def reduceLeftOption[U >: T](op: (U, T) ⇒ U): Option[U]

    Optionally applies a binary operator to all elements of this parallel iterable, going left to right.

    Optionally applies a binary operator to all elements of this parallel iterable, going left to right.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    op

    the binary operator.

    returns

    an option value containing the result of reduceLeft(op) if this parallel iterable is nonempty, None otherwise.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  75. 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
    ParIterableLikeGenTraversableOnce
  76. def reduceRight[U >: T](op: (T, U) ⇒ U): U

    Applies a binary operator to all elements of this parallel iterable, going right to left.

    Applies a binary operator to all elements of this parallel iterable, going right to left.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    op

    the binary operator.

    returns

    the result of inserting op between consecutive elements of this parallel iterable, going right to left:

    op(x_1, op(x_2, ..., op(x_{n-1}, x_n)...))

    where x1, ..., xn are the elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Exceptions thrown

    UnsupportedOperationException if this parallel iterable is empty.

  77. def reduceRightOption[U >: T](op: (T, U) ⇒ U): Option[U]

    Optionally applies a binary operator to all elements of this parallel iterable, going right to left.

    Optionally applies a binary operator to all elements of this parallel iterable, going right to left.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    op

    the binary operator.

    returns

    an option value containing the result of reduceRight(op) if this parallel iterable is nonempty, None otherwise.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  78. def repr: Repr
    Definition Classes
    ParIterableLikeGenTraversableLike
  79. 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
  80. def sameElements(that: GenIterable[A]): Boolean

    [use case] Checks if the other iterable collection contains the same elements in the same order as this parallel iterable.

    [use case]

    Checks if the other iterable collection contains the same elements in the same order as this parallel iterable.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    Note: will not terminate for infinite-sized collections.

    that

    the collection to compare with.

    returns

    true, if both collections contain the same elements in the same order, false otherwise.

    Definition Classes
    ParIterableLikeGenIterableLike
    Full Signature

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

  81. 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
    ParIterableLikeGenTraversableLike
    Full Signature

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

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

    Produces a collection containing cumulative results of applying the operator going left to right.

    Produces a collection containing cumulative results of applying the operator going left to right.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    That

    the actual type of the resulting collection

    z

    the initial value

    op

    the binary operator applied to the intermediate result and the element

    bf

    an implicit value of class CanBuildFrom which determines the result class That from the current representation type Repr and the new element type B.

    returns

    collection with intermediate results

    Definition Classes
    ParIterableLikeGenTraversableLike
  84. def scanRight[S, That](z: S)(op: (T, S) ⇒ S)(implicit bf: CanBuildFrom[Repr, S, That]): That

    Produces a collection containing cumulative results of applying the operator going right to left.

    Produces a collection containing cumulative results of applying the operator going right to left. The head of the collection is the last cumulative result.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    Example:

    List(1, 2, 3, 4).scanRight(0)(_ + _) == List(10, 9, 7, 4, 0)
    That

    the actual type of the resulting collection

    z

    the initial value

    op

    the binary operator applied to the intermediate result and the element

    bf

    an implicit value of class CanBuildFrom which determines the result class That from the current representation type Repr and the new element type B.

    returns

    collection with intermediate results

    Definition Classes
    ParIterableLikeGenTraversableLike
  85. def sequentially[S, That <: Parallel](b: (Sequential) ⇒ Parallelizable[S, That]): Repr
    Attributes
    protected[this]
  86. def sizeHintIfCheap: Int

    The size of this collection or iterator, if it can be cheaply computed

    The size of this collection or iterator, if it can be cheaply computed

    returns

    the number of elements in this collection or iterator, or -1 if the size cannot be determined cheaply

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

    Selects an interval of elements.

    Selects an interval of elements. The returned collection is made up of all elements x which satisfy the invariant:

    from <= indexOf(x) < until

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    unc_from

    the lowest index to include from this parallel iterable.

    unc_until

    the lowest index to EXCLUDE from this parallel iterable.

    returns

    a parallel iterable containing the elements greater than or equal to index from extending up to (but not including) index until of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableLike
  88. 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
    ParIterableLikeGenTraversableLike
  89. def splitAt(n: Int): (Repr, Repr)

    Splits this parallel iterable into two at a given position.

    Splits this parallel iterable into two at a given position. Note: c splitAt n is equivalent to (but possibly more efficient than) (c take n, c drop n).

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    n

    the position at which to split.

    returns

    a pair of parallel iterables consisting of the first n elements of this parallel iterable, and the other elements.

    Definition Classes
    ParIterableLikeGenTraversableLike
  90. def sum: A

    [use case] Sums up the elements of this collection.

    [use case]

    Sums up the elements of this collection.

    returns

    the sum of all elements in this parallel iterable of numbers of type Int. Instead of Int, any other type T with an implicit Numeric[T] implementation can be used as element type of the parallel iterable and as result type of sum. Examples of such types are: Long, Float, Double, BigInt.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def sum[U >: T](implicit num: Numeric[U]): U

  91. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  92. def tail: Repr

    Selects all elements except the first.

    Selects all elements except the first.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

    a parallel iterable consisting of all elements of this parallel iterable except the first one.

    Definition Classes
    ParIterableLikeGenTraversableLike
    Exceptions thrown

    UnsupportedOperationException if the parallel iterable is empty.

  93. def take(n: Int): Repr

    Selects first n elements.

    Selects first n elements.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    n

    the number of elements to take from this parallel iterable.

    returns

    a parallel iterable consisting only of the first n elements of this parallel iterable, or else the whole parallel iterable, if it has less than n elements. If n is negative, returns an empty parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableLike
  94. 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
    ParIterableLikeGenTraversableLike
  95. implicit def task2ops[R, Tp](tsk: SSCTask[R, Tp]): TaskOps[R, Tp]
    Attributes
    protected
  96. 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

  97. 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

  98. def to[Col[_]]: Col[A]

    [use case] Converts this parallel iterable into another by copying all elements.

    [use case]

    Converts this parallel iterable into another by copying all elements.

    Note: will not terminate for infinite-sized collections.

    Col

    The collection type to build.

    returns

    a new collection containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def to[Col[_]](implicit cbf: CanBuildFrom[Nothing, T, Col[T]]): Col[T]

  99. def toArray: Array[A]

    [use case] Converts this parallel iterable to an array.

    [use case]

    Converts this parallel iterable to an array.

    Note: will not terminate for infinite-sized collections.

    returns

    an array containing all elements of this parallel iterable. An ClassTag must be available for the element type of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def toArray[U >: T](implicit arg0: ClassTag[U]): Array[U]

  100. def toBuffer[U >: T]: Buffer[U]

    Uses the contents of this parallel iterable to create a new mutable buffer.

    Uses the contents of this parallel iterable to create a new mutable buffer.

    Note: will not terminate for infinite-sized collections.

    returns

    a buffer containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  101. def toIndexedSeq: immutable.IndexedSeq[T]

    Converts this parallel iterable to an indexed sequence.

    Converts this parallel iterable to an indexed sequence.

    Note: will not terminate for infinite-sized collections.

    returns

    an indexed sequence containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  102. def toIterable: ParIterable[T]

    Converts this parallel iterable to an iterable collection.

    Converts this parallel iterable to an iterable collection. Note that the choice of target Iterable is lazy in this default implementation as this TraversableOnce may be lazy and unevaluated (i.e. it may be an iterator which is only traversable once).

    Note: will not terminate for infinite-sized collections.

    returns

    an Iterable containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  103. def toIterator: scala.Iterator[T]

    Returns an Iterator over the elements in this parallel iterable.

    Returns an Iterator over the elements in this parallel iterable. Will return the same Iterator if this instance is already an Iterator.

    Note: will not terminate for infinite-sized collections.

    returns

    an Iterator containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  104. def toList: List[T]

    Converts this parallel iterable to a list.

    Converts this parallel iterable to a list.

    Note: will not terminate for infinite-sized collections.

    returns

    a list containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  105. def toMap[T, U]: collection.Map[T, U]

    [use case] Converts this parallel iterable to a map.

    [use case]

    Converts this parallel iterable to a map. This method is unavailable unless the elements are members of Tuple2, each ((T, U)) becoming a key-value pair in the map. Duplicate keys will be overwritten by later keys: if this is an unordered collection, which key is in the resulting map is undefined.

    Note: will not terminate for infinite-sized collections.

    returns

    a map of type immutable.Map[T, U] containing all key/value pairs of type (T, U) of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def toMap[K, V](implicit ev: <:<[T, (K, V)]): immutable.ParMap[K, V]

  106. def toParArray: ParArray[T]
    Implicit
    This member is added by an implicit conversion from ParIterableLike[T, Repr, Sequential] to CollectionsHaveToParArray[ParIterableLike[T, Repr, Sequential], T] performed by method CollectionsHaveToParArray in scala.collection.parallel. This conversion will take place only if an implicit value of type (ParIterableLike[T, Repr, Sequential]) ⇒ GenTraversableOnce[T] is in scope.
    Definition Classes
    CollectionsHaveToParArray
  107. def toParCollection[U >: T, That](cbf: () ⇒ Combiner[U, That]): That
    Attributes
    protected
  108. def toParMap[K, V, That](cbf: () ⇒ Combiner[(K, V), That])(implicit ev: <:<[T, (K, V)]): That
    Attributes
    protected
  109. def toSeq: ParSeq[T]

    Converts this parallel iterable to a sequence.

    Converts this parallel iterable to a sequence. As with toIterable, it's lazy in this default implementation, as this TraversableOnce may be lazy and unevaluated.

    Note: will not terminate for infinite-sized collections.

    returns

    a sequence containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  110. def toSet[U >: T]: immutable.ParSet[U]

    Converts this parallel iterable to a set.

    Converts this parallel iterable to a set.

    Note: will not terminate for infinite-sized collections.

    returns

    a set containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  111. def toStream: Stream[T]

    Converts this parallel iterable to a stream.

    Converts this parallel iterable to a stream.

    returns

    a stream containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  112. def toString(): String

    Creates a String representation of this object.

    Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.

    returns

    a String representation of the object.

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

    Converts this parallel iterable to an unspecified Traversable.

    Converts this parallel iterable to an unspecified Traversable. Will return the same collection if this instance is already Traversable.

    Note: will not terminate for infinite-sized collections.

    returns

    a Traversable containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  114. def toVector: Vector[T]

    Converts this parallel iterable to a Vector.

    Converts this parallel iterable to a Vector.

    Note: will not terminate for infinite-sized collections.

    returns

    a vector containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  115. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  116. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  117. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native()
  118. def withFilter(pred: (T) ⇒ Boolean): Repr
  119. def wrap[R](body: ⇒ R): NonDivisible[R]
    Attributes
    protected
  120. def zip[B](that: GenIterable[B]): ParIterable[(A, B)]

    [use case] Returns a parallel iterable formed from this parallel iterable and another iterable collection by combining corresponding elements in pairs.

    [use case]

    Returns a parallel iterable formed from this parallel iterable and another iterable collection by combining corresponding elements in pairs. If one of the two collections is longer than the other, its remaining elements are ignored.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    B

    the type of the second half of the returned pairs

    that

    The iterable providing the second half of each result pair

    returns

    a new parallel iterable containing pairs consisting of corresponding elements of this parallel iterable and that. The length of the returned collection is the minimum of the lengths of this parallel iterable and that.

    Definition Classes
    ParIterableLikeGenIterableLike
    Full Signature

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

  121. def zipAll[B](that: Iterable[B], thisElem: A, thatElem: B): ParIterable[(A, B)]

    [use case] Returns a parallel iterable formed from this parallel iterable and another iterable collection by combining corresponding elements in pairs.

    [use case]

    Returns a parallel iterable formed from this parallel iterable and another iterable collection by combining corresponding elements in pairs. If one of the two collections is shorter than the other, placeholder elements are used to extend the shorter collection to the length of the longer.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    B

    the type of the second half of the returned pairs

    that

    The iterable providing the second half of each result pair

    thisElem

    the element to be used to fill up the result if this parallel iterable is shorter than that.

    thatElem

    the element to be used to fill up the result if that is shorter than this parallel iterable.

    returns

    a new parallel iterable containing pairs consisting of corresponding elements of this parallel iterable and that. The length of the returned collection is the maximum of the lengths of this parallel iterable and that. If this parallel iterable is shorter than that, thisElem values are used to pad the result. If that is shorter than this parallel iterable, thatElem values are used to pad the result.

    Definition Classes
    ParIterableLikeGenIterableLike
    Full Signature

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

  122. def zipWithIndex: ParIterable[(A, Int)]

    [use case] Zips this parallel iterable with its indices.

    [use case]

    Zips this parallel iterable with its indices.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

    A new parallel iterable containing pairs consisting of all elements of this parallel iterable paired with their index. Indices start at 0.

    Definition Classes
    ParIterableLikeGenIterableLike
    Full Signature

    def zipWithIndex[U >: T, That](implicit bf: CanBuildFrom[Repr, (U, Int), That]): That

    Example:
    1. List("a", "b", "c").zipWithIndex = List(("a", 0), ("b", 1), ("c", 2))

  123. def [B](y: B): (ParIterableLike[T, Repr, Sequential], B)
    Implicit
    This member is added by an implicit conversion from ParIterableLike[T, Repr, Sequential] to ArrowAssoc[ParIterableLike[T, Repr, Sequential]] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc

Deprecated Value Members

  1. def /:[S](z: S)(op: (S, T) ⇒ S): S

    Applies a binary operator to a start value and all elements of this parallel iterable, going left to right.

    Applies a binary operator to a start value and all elements of this parallel iterable, going left to right.

    Note: /: is alternate syntax for foldLeft; z /: xs is the same as xs foldLeft z.

    Examples:

    Note that the folding function used to compute b is equivalent to that used to compute c.

    scala> val a = List(1,2,3,4)
    a: List[Int] = List(1, 2, 3, 4)
    
    scala> val b = (5 /: a)(_+_)
    b: Int = 15
    
    scala> val c = (5 /: a)((x,y) => x + y)
    c: Int = 15

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    z

    the start value.

    op

    the binary operator.

    returns

    the result of inserting op between consecutive elements of this parallel iterable, going left to right with the start value z on the left:

    op(...op(op(z, x_1), x_2), ..., x_n)

    where x1, ..., xn are the elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Annotations
    @deprecated
    Deprecated

    (Since version 2.12.10) Use foldLeft instead of /:

  2. def :\[S](z: S)(op: (T, S) ⇒ S): S

    Applies a binary operator to all elements of this parallel iterable and a start value, going right to left.

    Applies a binary operator to all elements of this parallel iterable and a start value, going right to left.

    Note: :\ is alternate syntax for foldRight; xs :\ z is the same as xs foldRight z.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    Examples:

    Note that the folding function used to compute b is equivalent to that used to compute c.

    scala> val a = List(1,2,3,4)
    a: List[Int] = List(1, 2, 3, 4)
    
    scala> val b = (a :\ 5)(_+_)
    b: Int = 15
    
    scala> val c = (a :\ 5)((x,y) => x + y)
    c: Int = 15
    z

    the start value

    op

    the binary operator

    returns

    the result of inserting op between consecutive elements of this parallel iterable, going right to left with the start value z on the right:

    op(x_1, op(x_2, ... op(x_n, z)...))

    where x1, ..., xn are the elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Annotations
    @deprecated
    Deprecated

    (Since version 2.12.10) Use foldRight instead of :\

  3. def formatted(fmtstr: String): String

    Returns string formatted according to given format string.

    Returns string formatted according to given format string. Format strings are as for String.format (@see java.lang.String.format).

    Implicit
    This member is added by an implicit conversion from ParIterableLike[T, Repr, Sequential] to StringFormat[ParIterableLike[T, Repr, Sequential]] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @deprecated @inline()
    Deprecated

    (Since version 2.12.16) Use formatString.format(value) instead of value.formatted(formatString), or use the f"" string interpolator. In Java 15 and later, formatted resolves to the new method in String which has reversed parameters.

  4. def view: IterableView[T, Sequential]
    Annotations
    @deprecated
    Deprecated

    (Since version 2.11.0) use .seq.view instead

Inherited from HasNewCombiner[T, Repr]

Inherited from Parallel

Inherited from CustomParallelizable[T, Repr]

Inherited from GenIterableLike[T, Repr]

Inherited from GenTraversableLike[T, Repr]

Inherited from Parallelizable[T, Repr]

Inherited from GenTraversableOnce[T]

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion CollectionsHaveToParArray from ParIterableLike[T, Repr, Sequential] to CollectionsHaveToParArray[ParIterableLike[T, Repr, Sequential], T]

Inherited by implicit conversion any2stringadd from ParIterableLike[T, Repr, Sequential] to any2stringadd[ParIterableLike[T, Repr, Sequential]]

Inherited by implicit conversion StringFormat from ParIterableLike[T, Repr, Sequential] to StringFormat[ParIterableLike[T, Repr, Sequential]]

Inherited by implicit conversion Ensuring from ParIterableLike[T, Repr, Sequential] to Ensuring[ParIterableLike[T, Repr, Sequential]]

Inherited by implicit conversion ArrowAssoc from ParIterableLike[T, Repr, Sequential] to ArrowAssoc[ParIterableLike[T, Repr, Sequential]]

Ungrouped