scala.collection.parallel

ParIterableLike

trait ParIterableLike [+T, +Repr <: ParIterable[T], +Sequential <: 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]. Parallel iterators 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.

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.

The method:

    def threshold(sz: Int, p: Int): Int

provides an estimate on the minimum number of elements the collection has before the splitting stops and depends on the number of elements in the collection. A rule of the thumb is the number of elements divided by 8 times the parallelism level. This method may be overridden in concrete implementations if necessary.

Since this trait extends the Iterable 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, parallelIterator, 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
HasNewCombiner[T, Repr], Parallel, CustomParallelizable[T, Repr], GenIterableLike[T, Repr], GenTraversableLike[T, Repr], Parallelizable[T, Repr], GenTraversableOnce[T], AnyRef, Any
Known Subclasses
Appended, Appended, Forced, Forced, Mapped, Mapped, ParArray, ParHashMap, ParHashMap, ParHashSet, ParHashSet, ParIterable, ParIterable, ParIterable, ParIterableView, ParIterableViewLike, ParMap, ParMap, ParMap, ParMapLike, ParMapLike, ParRange, ParSeq, ParSeq, ParSeq, ParSeqLike, ParSeqView, ParSeqViewLike, ParSet, ParSet, ParSet, ParSetLike, ParSetLike, ParVector, Patched, Prepended, Reversed, Sliced, Sliced, Transformed, Transformed, Zipped, Zipped, ZippedAll, ZippedAll
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  1. ParIterableLike
  2. HasNewCombiner
  3. Parallel
  4. CustomParallelizable
  5. GenIterableLike
  6. GenTraversableLike
  7. Parallelizable
  8. GenTraversableOnce
  9. AnyRef
  10. Any
Visibility
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  2. All

Type Members

  1. trait Accessor [R, Tp] extends StrictSplitterCheckTask[R, Tp]

    Standard accessor task that iterates over the elements of the collection.

  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. class Composite [FR, SR, R, First <: ParIterableLike.this.StrictSplitterCheckTask[FR, _], Second <: ParIterableLike.this.StrictSplitterCheckTask[SR, _]] extends NonDivisibleTask[R, Composite[FR, SR, R, First, Second]]

    Attributes
    protected[this] abstract

  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. class ParComposite [FR, SR, R, First <: ParIterableLike.this.StrictSplitterCheckTask[FR, _], Second <: ParIterableLike.this.StrictSplitterCheckTask[SR, _]] extends Composite[FR, SR, R, First, Second]

    Performs two tasks in parallel, and waits for both to finish.

  27. trait ParIterator extends IterableSplitter[T]

    Parallel iterators are split iterators that have additional accessor and transformer methods defined in terms of methods next and hasNext.

  28. class Partition [U >: T, This >: Repr] extends Transformer[(Combiner[U, This], Combiner[U, This]), Partition[U, This]]

    Attributes
    protected[this]

  29. class Product [U >: T] extends Accessor[U, Product[U]]

    Attributes
    protected[this]

  30. class Reduce [U >: T] extends Accessor[Option[U], Reduce[U]]

    Attributes
    protected[this]

  31. class ResultMapping [R, Tp, R1] extends NonDivisibleTask[R1, ResultMapping[R, Tp, R1]]

    Attributes
    protected[this] abstract

  32. type SSCTask [R, Tp] = StrictSplitterCheckTask[R, Tp]

  33. 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 Product with Serializable

    Attributes
    protected[this]

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

    Attributes
    protected[this]

  35. trait ScanTree [U >: T] extends AnyRef

    Attributes
    protected[this]

  36. class SeqComposite [FR, SR, R, First <: ParIterableLike.this.StrictSplitterCheckTask[FR, _], Second <: ParIterableLike.this.StrictSplitterCheckTask[SR, _]] extends Composite[FR, SR, R, First, Second]

    Sequentially performs one task after another.

  37. trait SignalContextPassingIterator [+IterRepr <: ParIterator] extends ParIterator

    A stackable modification that ensures signal contexts get passed along the iterators.

  38. trait SignallingOps [PI <: DelegatedSignalling] extends AnyRef

  39. class Slice [U >: T, This >: Repr] extends Transformer[Combiner[U, This], Slice[U, This]]

    Attributes
    protected[this]

  40. class Span [U >: T, This >: Repr] extends Transformer[(Combiner[U, This], Combiner[U, This]), Span[U, This]]

    Attributes
    protected[this]

  41. class SplitAt [U >: T, This >: Repr] extends Transformer[(Combiner[U, This], Combiner[U, This]), SplitAt[U, This]]

    Attributes
    protected[this]

  42. trait StrictSplitterCheckTask [R, Tp] extends Task[R, Tp]

    Attributes
    protected

  43. class Sum [U >: T] extends Accessor[U, Sum[U]]

    Attributes
    protected[this]

  44. class Take [U >: T, This >: Repr] extends Transformer[Combiner[U, This], Take[U, This]]

    Attributes
    protected[this]

  45. class TakeWhile [U >: T, This >: Repr] extends Transformer[(Combiner[U, This], Boolean), TakeWhile[U, This]]

    Attributes
    protected[this]

  46. trait TaskOps [R, Tp] extends AnyRef

  47. class ToParCollection [U >: T, That] extends Transformer[Combiner[U, That], ToParCollection[U, That]]

    Attributes
    protected[this]

  48. class ToParMap [K, V, That] extends Transformer[Combiner[(K, V), That], ToParMap[K, V, That]]

    Attributes
    protected[this]

  49. trait Transformer [R, Tp] extends Accessor[R, Tp]

    Attributes
    protected

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

    Attributes
    protected[this]

  51. class ZipAll [U >: T, S, That] extends Transformer[Combiner[(U, S), That], ZipAll[U, S, That]]

    Attributes
    protected[this]

Abstract Value Members

  1. def newCombiner : Combiner[T, Repr]

    Attributes
    protected[this] abstract
    Definition Classes
    HasNewCombiner

  2. def seq : Sequential

    Attributes
    abstract
    Definition Classes
    ParIterableLike → Parallelizable → GenTraversableOnce

  3. def size : Int

    The size of this general iterable collection .

    The size of this general iterable collection .

    Note: will not terminate for infinite-sized collections.

    returns

    the number of elements in this general iterable collection .

    Attributes
    abstract
    Definition Classes
    GenTraversableLike → GenTraversableOnce

  4. 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] abstract

  5. 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 iterable collection . By default the string prefix is the simple name of the collection class general iterable collection .

    Attributes
    abstract
    Definition Classes
    GenTraversableLike

Concrete Value Members

  1. def != (arg0: AnyRef): Boolean

    Attributes
    final
    Definition Classes
    AnyRef

  2. def != (arg0: Any): Boolean

    Test two objects for inequality.

    Test two objects for inequality.

    returns

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

    Attributes
    final
    Definition Classes
    Any

  3. def ## (): Int

    Equivalent to x.hashCode except for boxed numeric types.

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

    returns

    a hash value consistent with ==

    Attributes
    final
    Definition Classes
    AnyRef → Any

  4. def ++ [B] (that: GenTraversableOnce[B]): GenIterable[B]

    [use case] Concatenates this general iterable collection with the elements of a traversable collection.

    [use case]

    Concatenates this general iterable collection with the elements of a traversable collection.

    B

    the element type of the returned collection.

    that

    the traversable to append.

    returns

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

    Attributes
    abstract
    Definition Classes
    GenTraversableLike

  5. def ++ [U >: T, That] (that: GenTraversableOnce[U])(implicit bf: CanBuildFrom[Repr, U, That]): That

    Concatenates this general iterable collection with the elements of a traversable collection.

    Concatenates this general iterable collection with the elements of a traversable collection.

    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 and the new element type B.

    returns

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

    Definition Classes
    ParIterableLike → GenTraversableLike

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

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

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

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

    z

    the start value.

    op

    the binary operator.

    returns

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

                op(...op(op(z, x,,1,,), x,,2,,), ..., x,,n,,)

    where x,,1,,, ..., x,,n,, are the elements of this general iterable collection .

    Definition Classes
    ParIterableLike → GenTraversableOnce

  7. def /:\ [A1 >: T] (z: A1)(op: (A1, A1) ⇒ A1): A1

    A syntactic sugar for out of order folding.

    A syntactic sugar for out of order folding. See fold.

    Definition Classes
    GenTraversableOnce

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

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

    Applies a binary operator to all elements of this general iterable collection 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.

    z

    the start value

    op

    the binary operator

    returns

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

                op(x,,1,,, op(x,,2,,, ... op(x,,n,,, z)...))

    where x,,1,,, ..., x,,n,, are the elements of this general iterable collection .

    Definition Classes
    ParIterableLike → GenTraversableOnce

  9. def == (arg0: AnyRef): Boolean

    Attributes
    final
    Definition Classes
    AnyRef

  10. def == (arg0: Any): Boolean

    Test two objects for equality.

    Test two objects for equality.

    returns

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

    Attributes
    final
    Definition Classes
    Any

  11. 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 list, while combop would concatenate two lists 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)

    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

  12. 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.

    Attributes
    final
    Definition Classes
    Any

  13. def bf2seq [S, That] (bf: CanBuildFrom[Repr, S, That]): CanBuildFrom[Sequential, S, That]

    Attributes
    protected[this]

  14. implicit def builder2ops [Elem, To] (cb: Builder[Elem, To]): BuilderOps[Elem, To]

    Attributes
    protected implicit

  15. def canEqual (other: Any): Boolean

  16. def cbfactory : () ⇒ Combiner[T, Repr]

    Attributes
    protected[this]

  17. 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()

  18. def collect [B] (pf: PartialFunction[T, B]): GenIterable[B]

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

    [use case]

    Builds a new collection by applying a partial function to all elements of this general iterable collection

    on which the function is defined.

    B

    the element type of the returned collection.

    pf

    the partial function which filters and maps the general iterable collection .

    returns

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

    Attributes
    abstract
    Definition Classes
    GenTraversableLike

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

    Builds a new collection by applying a partial function to all elements of this general iterable collection

    Builds a new collection by applying a partial function to all elements of this general iterable collection

    on which the function is defined.

    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.

    pf

    the partial function which filters and maps the general iterable collection .

    bf

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

    returns

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

    Definition Classes
    ParIterableLike → GenTraversableLike

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

    Definition Classes
    ParIterableLike → GenTraversableOnce

  21. def copyToArray (xs: Array[T], start: Int): Unit

    [use case] Copies values of this general iterable collection to an array.

    [use case]

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

    xs

    the array to fill.

    start

    the starting index.

    Attributes
    abstract
    Definition Classes
    GenTraversableOnce

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

    Copies values of this general iterable collection to an array.

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

    Note: will not terminate for infinite-sized collections.

    xs

    the array to fill.

    start

    the starting index.

    Definition Classes
    ParIterableLike → GenTraversableOnce

  23. def copyToArray (xs: Array[T]): Unit

    [use case] Copies values of this general iterable collection to an array.

    [use case]

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

    xs

    the array to fill.

    Attributes
    abstract
    Definition Classes
    GenTraversableOnce

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

    Copies values of this general iterable collection to an array.

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

    Note: will not terminate for infinite-sized collections.

    xs

    the array to fill.

    Definition Classes
    ParIterableLike → GenTraversableOnce

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

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

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

    p

    the predicate used to test elements.

    returns

    the number of elements satisfying the predicate p.

    Definition Classes
    ParIterableLike → GenTraversableOnce

  26. def debugBuffer : ArrayBuffer[String]

  27. implicit def delegatedSignalling2ops [PI <: DelegatedSignalling] (it: PI): SignallingOps[PI]

    Attributes
    protected implicit

  28. 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 general iterable collection .

    returns

    a general iterable collection consisting of all elements of this general iterable collection except the first n ones, or else the empty general iterable collection , if this general iterable collection has less than n elements.

    Definition Classes
    ParIterableLike → GenTraversableLike

  29. 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 general iterable collection that satisfy the predicate pred

    Definition Classes
    ParIterableLike → GenTraversableLike

  30. def eq (arg0: AnyRef): Boolean

    Tests whether the argument (arg0) is a reference to the receiver object (this).

    Tests whether the argument (arg0) 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.

    Attributes
    final
    Definition Classes
    AnyRef

  31. def equals (arg0: Any): Boolean

    The equality method for reference types.

    The equality method for reference types. See equals in Any.

    returns

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

    Definition Classes
    AnyRef → Any

  32. def exists (pred: (T) ⇒ Boolean): Boolean

    Tests whether a predicate holds for some element of this general iterable collection .

    Tests whether a predicate holds for some element of this general iterable collection .

    This method will use abort signalling capabilities. This means that splitters may send and read abort signals.

    returns

    true if p holds for some element, false otherwise

    Definition Classes
    ParIterableLike → GenTraversableOnce

  33. def filter (pred: (T) ⇒ Boolean): Repr

    Selects all elements of this general iterable collection which satisfy a predicate.

    Selects all elements of this general iterable collection which satisfy a predicate.

    returns

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

    Definition Classes
    ParIterableLike → GenTraversableLike

  34. def filterNot (pred: (T) ⇒ Boolean): Repr

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

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

    returns

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

    Definition Classes
    ParIterableLike → GenTraversableLike

  35. 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()

  36. def find (pred: (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.

    returns

    an option value with the element if such an element exists, or None otherwise

    Definition Classes
    ParIterableLike → GenTraversableOnce

  37. def flatMap [B] (f: (T) ⇒ GenTraversableOnce[B]): GenIterable[B]

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

    [use case]

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

    and concatenating the results.

    B

    the element type of the returned collection.

    f

    the function to apply to each element.

    returns

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

    Attributes
    abstract
    Definition Classes
    GenTraversableLike

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

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

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

    and concatenating the results.

    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.

    f

    the function to apply to each element.

    bf

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

    returns

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

    Definition Classes
    ParIterableLike → GenTraversableLike

  39. 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

  40. def foldLeft [S] (z: S)(op: (S, T) ⇒ S): S

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

    Applies a binary operator to a start value and all elements of this general iterable collection , 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 general iterable collection , going left to right with the start value z on the left:

                op(...op(z, x,,1,,), x,,2,,, ..., x,,n,,)

    where x,,1,,, ..., x,,n,, are the elements of this general iterable collection .

    Definition Classes
    ParIterableLike → GenTraversableOnce

  41. def foldRight [S] (z: S)(op: (T, S) ⇒ S): S

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

    Applies a binary operator to all elements of this general iterable collection 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 general iterable collection , going right to left with the start value z on the right:

                op(x,,1,,, op(x,,2,,, ... op(x,,n,,, z)...))

    where x,,1,,, ..., x,,n,, are the elements of this general iterable collection .

    Definition Classes
    ParIterableLike → GenTraversableOnce

  42. def forall (pred: (T) ⇒ Boolean): Boolean

    Tests whether a predicate holds for all elements of this general iterable collection .

    Tests whether a predicate holds for all elements of this general iterable collection .

    This method will use abort signalling capabilities. This means that splitters may send and read abort signals.

    returns

    true if p holds for all elements, false otherwise

    Definition Classes
    ParIterableLike → GenTraversableOnce

  43. def foreach [U] (f: (T) ⇒ U): Unit

    Applies a function f to all the elements of general iterable collection in a sequential order.

    Applies a function f to all the elements of general iterable collection in a sequential 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

  44. def getClass (): java.lang.Class[_ <: java.lang.Object]

    A representation that corresponds to the dynamic class of the receiver object.

    A representation that corresponds to the dynamic class of the receiver object.

    The nature of the representation is platform dependent.

    returns

    a representation that corresponds to the dynamic class of the receiver object.

    Attributes
    final
    Definition Classes
    AnyRef

  45. def groupBy [K] (f: (T) ⇒ K): ParMap[K, Repr]

    Partitions this general iterable collection into a map of general iterable collection s according to some discriminator function.

    Partitions this general iterable collection into a map of general iterable collection s 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 general iterable collection .

    K

    the type of keys returned by the discriminator function.

    f

    the discriminator function.

    returns

    A map from keys to general iterable collection s such that the following invariant holds:

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

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

    Definition Classes
    ParIterableLike → GenTraversableLike

  46. def hasDefiniteSize : Boolean

    Definition Classes
    ParIterableLike → GenTraversableOnce

  47. def hashCode (): Int

    The hashCode method for reference types.

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

    returns

    the hash code value for this object.

    Definition Classes
    AnyRef → Any

  48. def head : T

    Definition Classes
    GenIterableLike → GenTraversableLike

  49. def isEmpty : Boolean

    Tests whether the general iterable collection is empty.

    Tests whether the general iterable collection is empty.

    returns

    true if the general iterable collection contains no elements, false otherwise.

    Definition Classes
    GenIterableLike → GenTraversableOnce

  50. 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.

    Attributes
    final
    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. def isTraversableAgain : Boolean

    Tests whether this general iterable collection can be repeatedly traversed.

    Tests whether this general iterable collection can be repeatedly traversed.

    returns

    true

    Attributes
    final
    Definition Classes
    GenTraversableLike → GenTraversableOnce

  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
    ParIterableLike → GenIterableLike

  54. def map [B] (f: (T) ⇒ B): GenIterable[B]

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

    [use case]

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

    B

    the element type of the returned collection.

    f

    the function to apply to each element.

    returns

    a new collection of type That resulting from applying the given function f to each element of this general iterable collection and collecting the results.

    Attributes
    abstract
    Definition Classes
    GenTraversableLike

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

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

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

    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.

    f

    the function to apply to each element.

    bf

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

    returns

    a new collection of type That resulting from applying the given function f to each element of this general iterable collection and collecting the results.

    Definition Classes
    ParIterableLike → GenTraversableLike

  56. def max : T

    [use case] Finds the largest element.

    [use case]

    Finds the largest element.

    returns

    the largest element of this general iterable collection with respect to the ordering cmp.

    Attributes
    abstract
    Definition Classes
    GenTraversableOnce

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

    Finds the largest element.

    Finds the largest element.

    returns

    the largest element of this general iterable collection with respect to the ordering cmp.

    Definition Classes
    ParIterableLike → GenTraversableOnce

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

    Definition Classes
    ParIterableLike → GenTraversableOnce

  59. def min : T

    [use case] Finds the smallest element.

    [use case]

    Finds the smallest element.

    returns

    the smallest element of this general iterable collection with respect to the ordering cmp.

    Attributes
    abstract
    Definition Classes
    GenTraversableOnce

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

    Finds the smallest element.

    Finds the smallest element.

    returns

    the smallest element of this general iterable collection with respect to the ordering cmp.

    Definition Classes
    ParIterableLike → GenTraversableOnce

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

    Definition Classes
    ParIterableLike → GenTraversableOnce

  62. def mkString : String

    Displays all elements of this general iterable collection in a string.

    Displays all elements of this general iterable collection in a string.

    returns

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

    Definition Classes
    ParIterableLike → GenTraversableOnce

  63. def mkString (sep: String): String

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

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

    sep

    the separator string.

    returns

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

    Definition Classes
    ParIterableLike → GenTraversableOnce
    Example:

    1. List(1, 2, 3).mkString("|") = "1|2|3"

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

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

    Displays all elements of this general iterable collection 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 general iterable collection . 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 general iterable collection are separated by the string sep.

    Definition Classes
    ParIterableLike → GenTraversableOnce
    Example:

    1. List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"

  65. 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.

    Attributes
    final
    Definition Classes
    AnyRef

  66. def nonEmpty : Boolean

    Tests whether the general iterable collection is not empty.

    Tests whether the general iterable collection is not empty.

    returns

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

    Definition Classes
    ParIterableLike → GenTraversableOnce

  67. 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.

    Attributes
    final
    Definition Classes
    AnyRef

  68. 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.

    Attributes
    final
    Definition Classes
    AnyRef

  69. 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

  70. 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

  71. def partition (pred: (T) ⇒ Boolean): (Repr, Repr)

    Partitions this general iterable collection in two general iterable collection s according to a predicate.

    Partitions this general iterable collection in two general iterable collection s according to a predicate.

    returns

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

    Definition Classes
    ParIterableLike → GenTraversableLike

  72. def product : T

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

    [use case]

    Multiplies up the elements of this collection.

    returns

    the product of all elements of this general iterable collection with respect to the * operator in num.

    Attributes
    abstract
    Definition Classes
    GenTraversableOnce

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

    Multiplies up the elements of this collection.

    Multiplies up the elements of this collection.

    num

    an implicit parameter defining a set of numeric operations which includes the * operator to be used in forming the product.

    returns

    the product of all elements of this general iterable collection with respect to the * operator in num.

    Definition Classes
    ParIterableLike → GenTraversableOnce

  74. 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

  75. def reduceLeft [U >: T] (op: (U, T) ⇒ U): U

  76. def reduceLeftOption [U >: T] (op: (U, T) ⇒ U): Option[U]

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

    Optionally applies a binary operator to all elements of this general iterable collection , 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) is this general iterable collection is nonempty, None otherwise.

    Definition Classes
    ParIterableLike → GenTraversableOnce

  77. 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

  78. def reduceRight [U >: T] (op: (T, U) ⇒ U): U

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

    Applies a binary operator to all elements of this general iterable collection , 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 general iterable collection , going right to left:

                op(x,,1,,, op(x,,2,,, ..., op(x,,n-1,,, x,,n,,)...))

    where x,,1,,, ..., x,,n,, are the elements of this general iterable collection .

    Definition Classes
    ParIterableLike → GenTraversableOnce

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

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

    Optionally applies a binary operator to all elements of this general iterable collection , 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) is this general iterable collection is nonempty, None otherwise.

    Definition Classes
    ParIterableLike → GenTraversableOnce

  80. def repr : Repr

    Definition Classes
    ParIterableLike → GenTraversableLike

  81. 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

  82. def sameElements (that: GenIterable[T]): Boolean

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

    [use case]

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

    that

    the collection to compare with.

    returns

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

    Attributes
    abstract
    Definition Classes
    GenIterableLike

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

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

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

    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
    ParIterableLike → GenIterableLike

  84. def scan (z: T)(op: (T, T) ⇒ T): GenIterable[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.

    z

    neutral element for the operator op

    op

    the associative operator for the scan

    returns

    a collection containing the prefix scan of the elements in the original collection

    Attributes
    abstract

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

    Computes a prefix scan of the elements of the collection.

    Computes a prefix scan of the elements of the collection.

    Note: The neutral element z may be applied more than once.

    U

    element type of the resulting collection

    That

    type of the resulting collection

    z

    neutral element for the operator op

    op

    the associative operator for the scan

    returns

    a collection containing the prefix scan of the elements in the original collection

    Definition Classes
    ParIterableLike → GenTraversableLike

  86. def scanBlockSize : Int

    Attributes
    protected[this]

  87. def scanLeft [S, That] (z: S)(op: (S, T) ⇒ S)(implicit bf: CanBuildFrom[Repr, S, That]): That

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

    Produces a collection containing cummulative 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 and the new element type B.

    returns

    collection with intermediate results

    Definition Classes
    ParIterableLike → GenTraversableLike

  88. def scanRight [S, That] (z: S)(op: (T, S) ⇒ S)(implicit bf: CanBuildFrom[Repr, S, That]): That

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

    Produces a collection containing cummulative results of applying the operator going right to left. The head of the collection is the last cummulative 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 and the new element type B.

    returns

    collection with intermediate results

    Definition Classes
    ParIterableLike → GenTraversableLike

  89. def sequentially [S, That <: Parallel] (b: (Sequential) ⇒ Parallelizable[S, That]): Repr

    Attributes
    protected[this]

  90. 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.

    returns

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

    Definition Classes
    ParIterableLike → GenTraversableLike

  91. def span (pred: (T) ⇒ Boolean): (Repr, Repr)

    Splits this general iterable collection into a prefix/suffix pair according to a predicate.

    Splits this general iterable collection 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

  92. def splitAt (n: Int): (Repr, Repr)

    Splits this general iterable collection into two at a given position.

    Splits this general iterable collection 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 general iterable collection s consisting of the first n elements of this general iterable collection , and the other elements.

    Definition Classes
    ParIterableLike → GenTraversableLike

  93. def sum : T

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

    [use case]

    Sums up the elements of this collection.

    returns

    the sum of all elements of this general iterable collection with respect to the + operator in num.

    Attributes
    abstract
    Definition Classes
    GenTraversableOnce

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

    Sums up the elements of this collection.

    Sums up the elements of this collection.

    num

    an implicit parameter defining a set of numeric operations which includes the + operator to be used in forming the sum.

    returns

    the sum of all elements of this general iterable collection with respect to the + operator in num.

    Definition Classes
    ParIterableLike → GenTraversableOnce

  95. def synchronized [T0] (arg0: ⇒ T0): T0

    Attributes
    final
    Definition Classes
    AnyRef

  96. 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 general iterable collection consisting of all elements of this general iterable collection

    except the first one.

    Definition Classes
    GenTraversableLike

  97. 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

    Tt number of elements to take from this general iterable collection .

    returns

    a general iterable collection consisting only of the first n elements of this general iterable collection , or else the whole general iterable collection , if it has less than n elements.

    Definition Classes
    ParIterableLike → GenTraversableLike

  98. 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 general iterable collection of elements that satisy the predicate pred

    Definition Classes
    ParIterableLike → GenTraversableLike

  99. implicit def task2ops [R, Tp] (tsk: SSCTask[R, Tp]): TaskOps[R, Tp]

    Attributes
    protected implicit

  100. def threshold (sz: Int, p: Int): Int

    Some minimal number of elements after which this collection should be handled sequentially by different processors.

    Some minimal number of elements after which this collection should be handled sequentially by different processors.

    This method depends on the size of the collection and the parallelism level, which are both specified as arguments.

    sz

    the size based on which to compute the threshold

    p

    the parallelism level based on which to compute the threshold

    returns

    the maximum number of elements for performing operations sequentially

  101. def toArray : Array[T]

    [use case] Converts this general iterable collection to an array.

    [use case]

    Converts this general iterable collection to an array.

    Note: will not terminate for infinite-sized collections.

    returns

    an array containing all elements of this general iterable collection .

    Attributes
    abstract
    Definition Classes
    GenTraversableOnce

  102. def toArray [U >: T] (implicit arg0: ClassManifest[U]): Array[U]

    Converts this general iterable collection to an array.

    Converts this general iterable collection to an array.

    Note: will not terminate for infinite-sized collections.

    returns

    an array containing all elements of this general iterable collection .

    Definition Classes
    ParIterableLike → GenTraversableOnce

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

    Converts this general iterable collection to a mutable buffer.

    Converts this general iterable collection to a mutable buffer.

    Note: will not terminate for infinite-sized collections.

    returns

    a buffer containing all elements of this general iterable collection .

    Definition Classes
    ParIterableLike → GenTraversableOnce

  104. def toIndexedSeq [U >: T] : IndexedSeq[U]

    Converts this general iterable collection to an indexed sequence.

    Converts this general iterable collection to an indexed sequence.

    Note: will not terminate for infinite-sized collections.

    returns

    an indexed sequence containing all elements of this general iterable collection .

    Definition Classes
    ParIterableLike → GenTraversableOnce

  105. def toIterable : ParIterable[T]

    Converts this general iterable collection to an iterable collection.

    Converts this general iterable collection 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 general iterable collection .

    Definition Classes
    ParIterableLike → GenTraversableOnce

  106. def toIterator : Iterator[T]

    Returns an Iterator over the elements in this general iterable collection .

    Returns an Iterator over the elements in this general iterable collection . 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 general iterable collection .

    Definition Classes
    ParIterableLike → GenTraversableOnce

  107. def toList : List[T]

    Converts this general iterable collection to a list.

    Converts this general iterable collection to a list.

    Note: will not terminate for infinite-sized collections.

    returns

    a list containing all elements of this general iterable collection .

    Definition Classes
    ParIterableLike → GenTraversableOnce

  108. def toMap [T, U] : Map[T, U]

    [use case] Converts this general iterable collection to a map.

    [use case]

    Converts this general iterable collection 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 containing all elements of this general iterable collection .

    Attributes
    abstract
    Definition Classes
    GenTraversableOnce

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

    Converts this general iterable collection to a map.

    Converts this general iterable collection 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 containing all elements of this general iterable collection .

    Definition Classes
    ParIterableLike → GenTraversableOnce

  110. def toParCollection [U >: T, That] (cbf: () ⇒ Combiner[U, That]): That

    Attributes
    protected

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

    Attributes
    protected

  112. def toSeq : ParSeq[T]

    Converts this general iterable collection to a sequence.

    Converts this general iterable collection 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 general iterable collection .

    Definition Classes
    ParIterableLike → GenTraversableOnce

  113. def toSet [U >: T] : ParSet[U]

    Converts this general iterable collection to a set.

    Converts this general iterable collection to a set.

    Note: will not terminate for infinite-sized collections.

    returns

    a set containing all elements of this general iterable collection .

    Definition Classes
    ParIterableLike → GenTraversableOnce

  114. def toStream : Stream[T]

    Converts this general iterable collection to a stream.

    Converts this general iterable collection to a stream.

    Note: will not terminate for infinite-sized collections.

    returns

    a stream containing all elements of this general iterable collection .

    Definition Classes
    ParIterableLike → GenTraversableOnce

  115. 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

  116. def toTraversable : GenTraversable[T]

    Converts this general iterable collection to an unspecified Traversable.

    Converts this general iterable collection 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 general iterable collection .

    Definition Classes
    ParIterableLike → GenTraversableOnce

  117. def view : ParIterableView[T, Repr, Sequential]

  118. def wait (): Unit

    Attributes
    final
    Definition Classes
    AnyRef
    Annotations
    @throws()

  119. def wait (arg0: Long, arg1: Int): Unit

    Attributes
    final
    Definition Classes
    AnyRef
    Annotations
    @throws()

  120. def wait (arg0: Long): Unit

    Attributes
    final
    Definition Classes
    AnyRef
    Annotations
    @throws()

  121. def wrap [R] (body: ⇒ R): NonDivisible[R]

    Attributes
    protected

  122. def zip [B] (that: GenIterable[B]): GenIterable[(T, B)]

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

    [use case]

    Returns a general iterable collection formed from this general iterable collection 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.

    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 collection of type That containing pairs consisting of corresponding elements of this general iterable collection and that. The length of the returned collection is the minimum of the lengths of this general iterable collection and that.

    Attributes
    abstract
    Definition Classes
    GenIterableLike

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

    Returns a general iterable collection formed from this general iterable collection and another iterable collection by combining corresponding elements in pairs.

    Returns a general iterable collection formed from this general iterable collection 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.

    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 (A1, B) being admissible for that class, which means that an implicit instance of type CanBuildFrom[Repr, (A1, B), That]. is found.

    that

    The iterable providing the second half of each result pair

    bf

    an implicit value of class CanBuildFrom which determines the result class That from the current representation type Repr and the new element type (A1, B).

    returns

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

    Definition Classes
    ParIterableLike → GenIterableLike

  124. def zipAll [B] (that: Iterable[B], thisElem: T, thatElem: B): GenIterable[(T, B)]

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

    [use case]

    Returns a general iterable collection formed from this general iterable collection 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.

    that

    the iterable providing the second half of each result pair

    thisElem

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

    thatElem

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

    returns

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

    Attributes
    abstract
    Definition Classes
    GenIterableLike

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

    Returns a general iterable collection formed from this general iterable collection and another iterable collection by combining corresponding elements in pairs.

    Returns a general iterable collection formed from this general iterable collection 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.

    that

    the iterable providing the second half of each result pair

    thisElem

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

    thatElem

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

    returns

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

    Definition Classes
    ParIterableLike → GenIterableLike

  126. def zipWithIndex : GenIterable[(T, Int)]

    [use case] Zips this general iterable collection with its indices.

    [use case]

    Zips this general iterable collection with its indices.

    returns

    A new collection of type That containing pairs consisting of all elements of this general iterable collection paired with their index. Indices start at 0.

    Attributes
    abstract
    Definition Classes
    GenIterableLike

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

    Zips this general iterable collection with its indices.

    Zips this general iterable collection with its indices.

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

    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 (A1, Int) being admissible for that class, which means that an implicit instance of type CanBuildFrom[Repr, (A1, Int), That]. is found.

    returns

    A new collection of type That containing pairs consisting of all elements of this general iterable collection paired with their index. Indices start at 0.

    Definition Classes
    ParIterableLike → GenIterableLike

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