Selects an element by its index in the general sequence.

Example:

scala> val x = List(1, 2, 3, 4, 5)
x: List[Int] = List(1, 2, 3, 4, 5)

scala> x(3)
res1: Int = 4

The length of the general sequence.

Note: will not terminate for infinite-sized collections.

Note: xs.length and xs.size yield the same result.

A more refined version of the iterator found in the ParallelIterable trait, this iterator can be split into arbitrary subsets of iterators.

Defines the prefix of this object's toString representation.

Test two objects for inequality.

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 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)

A copy of the parallel iterable with an element prepended.

Note that :-ending operators are right associative (see example). A mnemonic for +: vs. :+ is: the COLon goes on the COLlection side.

Also, the original parallel iterable is not modified, so you will want to capture the result.

Example:

scala> val x = List(1)
x: List[Int] = List(1)

scala> val y = 2 +: x
y: List[Int] = List(2, 1)

scala> println(x)
List(1)

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.

A copy of this parallel iterable with an element appended.

A mnemonic for +: vs. :+ is: the COLon goes on the COLlection side.

Note: will not terminate for infinite-sized collections.

Example:

scala> val a = List(1)
a: List[Int] = List(1)

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

scala> println(a)
List(1)

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

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

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).

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.

Create a copy of the receiver object.

The default implementation of the clone method is platform dependent.

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

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.

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.

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.

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.

Tests whether every element of this parallel iterable relates to the corresponding element of another parallel sequence by satisfying a test predicate.

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

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

Computes the multiset difference between this parallel iterable and another sequence.

Note: will not terminate for infinite-sized collections.

Builds a new parallel iterable from this parallel iterable without any duplicate elements.

Note: will not terminate for infinite-sized collections.

Selects all elements except first n ones.

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

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.

Tests whether this parallel iterable ends with the given parallel sequence.

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

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).

The equals method for arbitrary sequences. Compares this sequence to some other object.

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.

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

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

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.

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.

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)

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.

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.

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.

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.

Applies a function f to all the elements of parallel iterable in an undefined order.

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

Returns the runtime class representation of the object.

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.

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.

Hashcodes for GenSeq produce a value from the hashcodes of all the elements of the general sequence.

Selects the first element of this parallel iterable.

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

Optionally selects the first element.

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

Finds index of first occurrence of some value in this parallel iterable after or at some start index.

Note: may not terminate for infinite-sized collections.

Finds index of first occurrence of some value in this parallel iterable.

Note: may not terminate for infinite-sized collections.

Finds the first element satisfying some 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.

Finds index of first element satisfying some predicate.

Note: may not terminate for infinite-sized collections.

Selects all elements except the last.

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

Computes the multiset intersection between this parallel iterable and another sequence.

Note: may not terminate for infinite-sized collections.

Tests whether this general sequence contains given index.

The implementations of methods apply and isDefinedAt turn a Seq[A] into a PartialFunction[Int, A].

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.

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.

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.

Tests whether this parallel iterable can be repeatedly traversed.

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.

Selects the last element.

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

Finds index of last occurrence of some value in this parallel iterable before or at a given end index.

Finds index of last occurrence of some value in this parallel iterable.

Note: will not terminate for infinite-sized collections.

Finds the last element satisfying some 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 minimum integer value.

Finds index of last element satisfying some predicate.

Note: will not terminate for infinite-sized collections.

Optionally selects the last element.

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

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

Finds the largest element.

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

Finds the smallest element.

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

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

Equivalent to !(this eq that).

Tests whether the parallel iterable is not empty.

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

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

A copy of this parallel iterable with an element value appended until a given target length is reached.

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.

The default par implementation uses the combiner provided by this method to create a new parallel collection.

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

Produces a new parallel iterable where a slice of elements in this parallel iterable is replaced by another sequence.

Returns the length of the longest prefix whose elements all satisfy some predicate.

Note: may not terminate for infinite-sized collections.

Multiplies up the elements of this collection.

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.

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.

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.

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.

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.

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).

Returns new parallel iterable with elements in reversed order.

Note: will not terminate for infinite-sized collections.

Builds a new collection by applying a function to all elements of this parallel iterable and collecting the results in reversed order.

Note: will not terminate for infinite-sized collections.

Note: xs.reverseMap(f) is the same as xs.reverse.map(f) but might be more efficient.

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.

Computes a prefix scan of the elements of the collection.

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

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.

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)

Returns the length of the longest segment of elements starting at a given position satisfying some 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.

The size of this parallel iterable.

Note: will not terminate for infinite-sized collections.

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

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.

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.

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.

Tests whether this parallel iterable contains the given sequence at a given index.

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

Tests whether this general sequence starts with the given sequence.

Sums up the elements of this collection.

Selects all elements except the first.

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

Selects first n elements.

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

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.

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.