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

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

Known Subclasses

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

Ordering

Alphabetic
By Inheritance

Inherited

ParIterableLike
HasNewCombiner
Parallel
CustomParallelizable
GenIterableLike
GenTraversableLike
Parallelizable
GenTraversableOnce
AnyRef
Any

Implicitly

by CollectionsHaveToParArray
by any2stringadd
by StringFormat
by Ensuring
by ArrowAssoc

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Visibility

Public
All

Type Members

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Attributes
protected[this]

Abstract Value Members

abstract def newCombiner: Combiner[T, Repr]

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

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

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

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
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
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
def ++[B](that: GenTraversableOnce[B]): ParIterable[B]
[use case] Returns a new parallel iterable containing the elements from the left hand operand followed by the elements from the right hand operand.
[use case]
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.
Example:
```
scala> val a = List(1)
a: List[Int] = List(1)

scala> val b = List(2)
b: List[Int] = List(2)

scala> val c = a ++ b
c: List[Int] = List(1, 2)

scala> val d = List('a')
d: List[Char] = List(a)

scala> val e = c ++ d
e: List[AnyVal] = List(1, 2, a)
```
B
the element type of the returned collection.
that
the traversable to append.
returns
a new parallel iterable which contains all elements of this parallel iterable followed by all elements of that.

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

Definition Classes
ParIterableLike → GenTraversableOnce
final def asInstanceOf[T0]: T0
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.
def bf2seq[S, That](bf: CanBuildFrom[Repr, S, That]): CanBuildFrom[Sequential, S, That]

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

Attributes
protected
def canEqual(other: Any): Boolean
def clone(): AnyRef
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[java.lang]
Definition Classes
AnyRef
Annotations
@throws( ... )
Note
not specified by SLS as a member of AnyRef
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
ParIterableLike → GenTraversableLike
Full Signature
def collect[S, That](pf: PartialFunction[T, S])(implicit bf: CanBuildFrom[Repr, S, That]): That
def combinerFactory[S, That](cbf: () ⇒ Combiner[S, That]): CombinerFactory[S, That]

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

Attributes
protected[this]
def copyToArray(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
ParIterableLike → GenTraversableOnce
Full Signature
def copyToArray[U >: T](xs: Array[U], start: Int, len: Int): Unit
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
ParIterableLike → GenTraversableOnce
Full Signature
def copyToArray[U >: T](xs: Array[U], start: Int): Unit
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
ParIterableLike → GenTraversableOnce
Full Signature
def copyToArray[U >: T](xs: Array[U]): Unit
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
ParIterableLike → GenTraversableOnce
def debugBuffer: ArrayBuffer[String]
implicit def delegatedSignalling2ops[PI <: DelegatedSignalling](it: PI): SignallingOps[PI]

Attributes
protected
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.

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

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

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

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

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

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

Definition Classes
ParIterableLike → GenTraversableLike → GenTraversableOnce
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
@inline()
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
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
ParIterableLike → GenTraversableLike
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
ParIterableLike → GenTraversableOnce
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
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
ParIterableLike → GenTraversableLike
Exceptions thrown
NoSuchElementException if the parallel iterable is empty.
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
ParIterableLike → GenTraversableLike
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
ParIterableLike → GenTraversableLike
Exceptions thrown
UnsupportedOperationException if the parallel iterable is empty.
def initTaskSupport(): Unit

Attributes
protected
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
ParIterableLike → GenTraversableOnce
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
def isStrictSplitterCollection: Boolean
Denotes whether this parallel collection has strict splitters.
Denotes whether this parallel collection has strict splitters.
This is true in general, and specific collection instances may choose to override this method. Such collections will fail to execute methods which rely on splitters being strict, i.e. returning a correct value in the remaining method.
This method helps ensure that such failures occur on method invocations, rather than later on and in unpredictable ways.
final def isTraversableAgain: Boolean
Tests whether this parallel iterable can be repeatedly traversed.
Tests whether this parallel iterable can be repeatedly traversed.
returns
true

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

Definition Classes
ParIterableLike → GenIterableLike
def last: T
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
ParIterableLike → GenTraversableLike
Exceptions thrown
NoSuchElementException If the parallel iterable is empty.
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
ParIterableLike → GenTraversableLike
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
ParIterableLike → GenTraversableLike
Full Signature
def map[S, That](f: (T) ⇒ S)(implicit bf: CanBuildFrom[Repr, S, That]): That
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
ParIterableLike → GenTraversableOnce
Full Signature
def max[U >: T](implicit ord: Ordering[U]): T
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
ParIterableLike → GenTraversableOnce
Full Signature
def maxBy[S](f: (T) ⇒ S)(implicit cmp: Ordering[S]): T
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
ParIterableLike → GenTraversableOnce
Full Signature
def min[U >: T](implicit ord: Ordering[U]): T
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
ParIterableLike → GenTraversableOnce
Full Signature
def minBy[S](f: (T) ⇒ S)(implicit cmp: Ordering[S]): T
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
ParIterableLike → GenTraversableOnce
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
ParIterableLike → GenTraversableOnce
Example:
1. List(1, 2, 3).mkString("|") = "1|2|3"
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
ParIterableLike → GenTraversableOnce
Example:
1. List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
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
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
ParIterableLike → GenTraversableOnce
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
Note
not specified by SLS as a member of AnyRef
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
Note
not specified by SLS as a member of AnyRef
def par: Repr
Returns a parallel implementation of this collection.
Returns a parallel implementation of this collection.
For most collection types, this method creates a new parallel collection by copying all the elements. For these collection, par takes linear time. Mutable collections in this category do not produce a mutable parallel collection that has the same underlying dataset, so changes in one collection will not be reflected in the other one.
Specific collections (e.g. ParArray or mutable.ParHashMap) override this default behaviour by creating a parallel collection which shares the same underlying dataset. For these collections, par takes constant or sublinear time.
All parallel collections return a reference to themselves.
returns
a parallel implementation of this collection

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

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

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

Definition Classes
ParIterableLike → GenTraversableOnce
def reduceRight[U >: T](op: (T, U) ⇒ U): U
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, ..., x_n are the elements of this parallel iterable.
Definition Classes
ParIterableLike → GenTraversableOnce
Exceptions thrown
UnsupportedOperationException if this parallel iterable is empty.
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
ParIterableLike → GenTraversableOnce
def repr: Repr

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

Attributes
protected
def sameElements(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
ParIterableLike → GenIterableLike
Full Signature
def sameElements[U >: T](that: GenIterable[U]): Boolean
def scan(z: T)(op: (T, T) ⇒ T): ParIterable[T]
[use case] Computes a prefix scan of the elements of the collection.
[use case]
Computes a prefix scan of the elements of the collection.
Note: The neutral element z may be applied more than once.
z
neutral element for the operator op
op
the associative operator for the scan
returns
a new parallel iterable containing the prefix scan of the elements in this parallel iterable

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

Attributes
protected[this]
def scanLeft[S, That](z: S)(op: (S, T) ⇒ S)(implicit bf: CanBuildFrom[Repr, S, That]): That
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
ParIterableLike → GenTraversableLike
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
ParIterableLike → GenTraversableLike
def sequentially[S, That <: Parallel](b: (Sequential) ⇒ Parallelizable[S, That]): Repr

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

Definition Classes
ParIterableLike → GenTraversableLike
def splitAt(n: Int): (Repr, Repr)
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
ParIterableLike → GenTraversableLike
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
ParIterableLike → GenTraversableOnce
Full Signature
def sum[U >: T](implicit num: Numeric[U]): U
final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
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
ParIterableLike → GenTraversableLike
Exceptions thrown
UnsupportedOperationException if the parallel iterable is empty.
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.

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

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

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

See also
scala.collection.parallel.TaskSupport
def tasksupport_=(ts: TaskSupport): Unit
Changes the task support object which is responsible for scheduling and load-balancing tasks to processors.
Changes the task support object which is responsible for scheduling and load-balancing tasks to processors.
A task support object can be changed in a parallel collection after it has been created, but only during a quiescent period, i.e. while there are no concurrent invocations to parallel collection methods.
Here is a way to change the task support of a parallel collection:
```
import scala.collection.parallel._
val pc = mutable.ParArray(1, 2, 3)
pc.tasksupport = new ForkJoinTaskSupport(
  new java.util.concurrent.ForkJoinPool(2))
```
See also
scala.collection.parallel.TaskSupport
def to[Col[_]]: 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
ParIterableLike → GenTraversableOnce
Full Signature
def to[Col[_]](implicit cbf: CanBuildFrom[Nothing, T, Col[T]]): Col[T]
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
ParIterableLike → GenTraversableOnce
Full Signature
def toArray[U >: T](implicit arg0: ClassTag[U]): Array[U]
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
ParIterableLike → GenTraversableOnce
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
ParIterableLike → GenTraversableOnce
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
ParIterableLike → GenTraversableOnce
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
ParIterableLike → GenTraversableOnce
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
ParIterableLike → GenTraversableOnce
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
ParIterableLike → GenTraversableOnce
Full Signature
def toMap[K, V](implicit ev: <:<[T, (K, V)]): immutable.ParMap[K, V]
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
def toParCollection[U >: T, That](cbf: () ⇒ Combiner[U, That]): That

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

Attributes
protected
def toSeq: ParSeq[T]
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
ParIterableLike → GenTraversableOnce
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
ParIterableLike → GenTraversableOnce
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
ParIterableLike → GenTraversableOnce
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
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
ParIterableLike → GenTraversableOnce
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
ParIterableLike → GenTraversableOnce
final def wait(): Unit

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

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

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

Attributes
protected
def zip[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
ParIterableLike → GenIterableLike
Full Signature
def zip[U >: T, S, That](that: GenIterable[S])(implicit bf: CanBuildFrom[Repr, (U, S), That]): That
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
ParIterableLike → GenIterableLike
Full Signature
def zipAll[S, U >: T, That](that: GenIterable[S], thisElem: U, thatElem: S)(implicit bf: CanBuildFrom[Repr, (U, S), That]): That
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
ParIterableLike → GenIterableLike
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))
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

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]

Packages

Package structure

Automatic imports

Guide

Using Collections

Creating Collections

Converting to and from Java Collections

ParIterableLike 

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

Type Members

Abstract Value Members

Concrete Value Members

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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