ParallelArray (org.codehaus.gpars)

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groovyx.gpars.extra166y
[Java] Class ParallelArray

java.lang.Object
  AbstractParallelAnyArray.OUPap
      groovyx.gpars.extra166y.ParallelArray

All Implemented Interfaces:: java.lang.Iterable

public class ParallelArray
extends OUPap

An array supporting parallel operations.

A ParallelArray maintains a ForkJoinPool and an array in order to provide parallel aggregate operations. The main operations are to apply some procedure to each element, to map each element to a new element, to replace each element, to select a subset of elements based on matching a predicate or ranges of indices, and to reduce all elements into a single value such as a sum.

A ParallelArray is constructed by allocating, using, or copying an array, using one of the static factory methods create, createEmpty, createUsingHandoff and createFromCopy. Upon construction, the encapsulated array managed by the ParallelArray must not be shared between threads without external synchronization. In particular, as is the case with any array, access by another thread of an element of a ParallelArray while another operation is in progress has undefined effects.

The ForkJoinPool used to construct a ParallelArray can be shared safely by other threads (and used in other ParallelArrays). To avoid the overhead associated with creating multiple executors, it is often a good idea to use the defaultExecutor() across all ParallelArrays. However, you might choose to use different ones for the sake of controlling processor usage, isolating faults, and/or ensuring progress.

A ParallelArray is not a List. It relies on random access across array elements to support efficient parallel operations. However, a ParallelArray can be viewed and manipulated as a List, via method ParallelArray#asList#asList. The asList view allows incremental insertion and modification of elements while setting up a ParallelArray, generally before using it for parallel operations. Similarly, the list view may be useful when accessing the results of computations in sequential contexts. A ParallelArray may also be created using the elements of any other Collection, by constructing from the array returned by the Collection's toArray method. The effects of mutative asList operations may also be achieved directly using method setLimit along with element-by-element access methods get and set.

While ParallelArrays can be based on any kind of an object array, including "boxed" types such as Long, parallel operations on scalar "unboxed" type are likely to be substantially more efficient. For this reason, classes ParallelLongArray and ParallelDoubleArray are also supplied, and designed to smoothly interoperate with ParallelArrays. You should also use a ParallelLongArray for processing other integral scalar data (int, short, etc). And similarly use a ParallelDoubleArray for float data. (Further specializations for these other types would add clutter without significantly improving performance beyond that of the Long and Double versions.)

Most usages of ParallelArray involve sets of operations prefixed with range bounds, filters, and mappings (including mappings that combine elements from other ParallelArrays), using withBounds, withFilter, and withMapping, respectively. For example, aParallelArray.withFilter(aPredicate).all() creates a new ParallelArray containing only those elements matching the predicate. And for ParallelLongArrays a, b, and c, a.withMapping(CommonOps.longAdder(),b).withMapping(CommonOps.longAdder(),c).min() returns the minimum value of a[i]+b[i]+c[i] for all i. As illustrated below, a mapping often represents accessing some field or invoking some method of an element. These versions are typically more efficient than performing selections, then mappings, then other operations in multiple (parallel) steps. The basic ideas and usages of filtering and mapping are similar to those in database query systems such as SQL, but take a more restrictive form. Series of filter and mapping prefixes may each be cascaded, but all filter prefixes must precede all mapping prefixes, to ensure efficient execution in a single parallel step. In cases of combined mapping expressions, this rule is only dynamically enforced. For example, pa.withMapping(op, pb.withFilter(f)) will compile but throw an exception upon execution because the filter precedes the mapping.

While series of filters and mappings are allowed, it is usually more efficient to combine them into single filters or mappings when possible. For example pa.withMapping(addOne).withMapping(addOne) is generally less efficient than pa.withMapping(addTwo). Methods withIndexedFilter and withIndexedMapping may be useful when combining such expressions.

This class includes some reductions, such as min, that are commonly useful for most element types, as well as a combined version, summary, that computes all of them in a single parallel step, which is normally more efficient than computing each in turn.

The methods in this class are designed to perform efficiently with both large and small pools, even with single-thread pools on uniprocessors. However, there is some overhead in parallelizing operations, so short computations on small arrays might not execute faster than sequential versions, and might even be slower.

Sample usages. The main difference between programming with plain arrays and programming with aggregates is that you must separately define each of the component functions on elements. For example, the following returns the maximum Grade Point Average across all senior students, given a (fictional) Student class:

 import static Ops.*;
 class StudentStatistics {
   ParallelArray<Student> students = ...
   // ...
   public double getMaxSeniorGpa() {
     return students.withFilter(isSenior).withMapping(gpaField).max();
   }

   // helpers:
   static final class IsSenior implements Predicate<Student> {
     public boolean op(Student s) { return s.credits > 90; }
   }
   static final IsSenior isSenior = new IsSenior();
   static final class GpaField implements ObjectToDouble<Student> {
     public double op(Student s) { return s.gpa; }
   }
   static final GpaField gpaField = new GpaField();
 }

Nested Class Summary
`class`	`ParallelArray.AsList`
`class`	`ParallelArray.ListIter`
`static class`	`ParallelArray.ParallelArrayIterator`
`static interface`	`ParallelArray.SummaryStatistics` Summary statistics for a possibly bounded, filtered, and/or mapped ParallelArray.

Field Summary
`ParallelArray.AsList`	`listView` Lazily constructed list view

Constructor Summary
`protected ParallelArray(ForkJoinPool executor, java.lang.Object[] array, int limit)` Constructor for use by subclasses to create a new ParallelArray using the given executor, and initially using the supplied array, with effective size bound by the given limit.
`ParallelArray(ForkJoinPool executor, java.lang.Object[] array)` Trusted internal version of protected constructor.

Method Summary
`ParallelArray`	`addAll(java.lang.Object[] other)` Equivalent to `asList().addAll` but specialized for array arguments and likely to be more efficient.
`ParallelArray`	`addAll(ParallelArrayWithMapping other)` Appends all (possibly bounded, filtered, or mapped) elements of the given ParallelArray, resizing and/or reallocating this array if necessary.
`ParallelArray`	`all()` Returns a new ParallelArray holding all elements
`ParallelArray`	`all(java.lang.Class elementType)` Returns a new ParallelArray with the given element type holding all elements
`ParallelArray`	`allNonidenticalElements()` Returns a new ParallelArray containing only the non-null unique elements of this array (that is, without any duplicates), using reference identity to test for duplication.
`ParallelArray`	`allUniqueElements()` Returns a new ParallelArray containing only the non-null unique elements of this array (that is, without any duplicates), using each element's `equals` method to test for duplication.
`void`	`appendElement(java.lang.Object e)`
`void`	`apply(Procedure procedure)` Applies the given procedure to elements
`java.util.List`	`asList()` Returns a view of this ParallelArray as a List.
`int`	`binarySearch(java.lang.Object target)` Assuming this array is sorted, returns the index of an element equal to given target, or -1 if not present.
`int`	`binarySearch(java.lang.Object target, java.util.Comparator comparator)` Assuming this array is sorted with respect to the given comparator, returns the index of an element equal to given target, or -1 if not present.
`static ParallelArray`	`create(int size, java.lang.Class elementType, ForkJoinPool executor)` Creates a new ParallelArray using the given executor and an array of the given size constructed using the indicated base element type.
`static ParallelArray`	`createEmpty(int size, java.lang.Class elementType, ForkJoinPool executor)` Creates a new ParallelArray using the given executor and an array of the given size constructed using the indicated base element type, but with an initial effective size of zero, enabling incremental insertion via ParallelArray#asList#asList operations.
`static ParallelArray`	`createFromCopy(java.lang.Object[] source, ForkJoinPool executor)` Creates a new ParallelArray using the given executor and initially holding copies of the given source elements.
`static ParallelArray`	`createFromCopy(int size, java.lang.Object[] source, ForkJoinPool executor)` Creates a new ParallelArray using an array of the given size, initially holding copies of the given source truncated or padded with nulls to obtain the specified length.
`static ParallelArray`	`createUsingHandoff(java.lang.Object[] handoff, ForkJoinPool executor)` Creates a new ParallelArray initially using the given array and executor.
`ParallelArray`	`cumulate(Reducer reducer, java.lang.Object base)` Replaces each element with the running cumulation of applying the given reducer.
`static ForkJoinPool`	`defaultExecutor()` Returns a common default executor for use in ParallelArrays.
`java.lang.Object`	`get(int i)` Returns the element of the array at the given index
`java.lang.Object[]`	`getArray()` Returns the underlying array used for computations
`ForkJoinPool`	`getExecutor()` Returns the executor used for computations.
`boolean`	`hasAllEqualElements(ParallelArrayWithMapping other)` Returns true if all elements at the same relative positions of this and other array are equal.
`boolean`	`hasAllIdenticalElements(ParallelArrayWithMapping other)` Returns true if all elements at the same relative positions of this and other array are identical.
`int`	`indexOf(java.lang.Object target)` Returns the index of some element equal to given target, or -1 if not present
`void`	`insertElementAt(int index, java.lang.Object e)`
`void`	`insertSlotsAt(int index, int len)` Makes len slots available at index.
`java.util.Iterator`	`iterator()` Returns an iterator stepping through each element of the array up to the current limit.
`java.lang.Object`	`max(java.util.Comparator comparator)` Returns the maximum element, or null if empty
`java.lang.Object`	`max()` Returns the maximum element, or null if empty assuming that all elements are Comparables
`java.lang.Object`	`min(java.util.Comparator comparator)` Returns the minimum element, or null if empty
`java.lang.Object`	`min()` Returns the minimum element, or null if empty, assuming that all elements are Comparables
`java.lang.Object`	`precumulate(Reducer reducer, java.lang.Object base)` Replaces each element with the cumulation of applying the given reducer to all previous values, and returns the total reduction.
`java.lang.Object`	`reduce(Reducer reducer, java.lang.Object base)` Returns reduction of elements
`ParallelArray`	`removeAll(Predicate selector)` Removes from the array all elements for which the given selector holds.
`ParallelArray`	`removeConsecutiveDuplicates()` Removes consecutive elements that are equal (or null), shifting others leftward, and possibly decreasing size.
`ParallelArray`	`removeNulls()` Removes null elements, shifting others leftward, and possibly decreasing size.
`void`	`removeSlotAt(int index)`
`void`	`removeSlotsAt(int fromIndex, int toIndex)`
`void`	`replaceElementsWith(java.lang.Object[] a)`
`ParallelArray`	`replaceWithGeneratedValue(Generator generator)` Replaces elements with the results of applying the given generator.
`ParallelArray`	`replaceWithMappedIndex(IntToObject op)` Replaces elements with the results of applying the given mapping to their indices.
`ParallelArray`	`replaceWithMappedIndex(IntAndObjectToObject op)` Replaces elements with the results of applying the given mapping to each index and current element value
`ParallelArray`	`replaceWithMapping(Op op)` Replaces elements with the results of applying the given transform to their current values.
`ParallelArray`	`replaceWithMapping(BinaryOp combiner, ParallelArrayWithMapping other)` Replaces elements with results of applying `op(thisElement, otherElement)`
`ParallelArray`	`replaceWithMapping(BinaryOp combiner, java.lang.Object[] other)` Replaces elements with results of applying `op(thisElement, otherElement)`
`ParallelArray`	`replaceWithValue(java.lang.Object value)` Replaces elements with the given value.
`void`	`resizeArray(int newCap)`
`int`	`seqIndexOf(java.lang.Object target)`
`int`	`seqLastIndexOf(java.lang.Object target)`
`void`	`set(int i, java.lang.Object x)` Sets the element of the array at the given index to the given value
`void`	`setLimit(int newLimit)` Ensures that the underlying array can be accessed up to the given upper bound, reallocating and copying the underlying array to expand if necessary.
`int`	`size()` Returns the effective size of the underlying array.
`ParallelArray`	`sort(java.util.Comparator comparator)` Sorts the array.
`ParallelArray`	`sort()` Sorts the array, assuming all elements are Comparable.
`SummaryStatistics`	`summary(java.util.Comparator comparator)` Returns summary statistics, using the given comparator to locate minimum and maximum elements.
`SummaryStatistics`	`summary()` Returns summary statistics, assuming that all elements are Comparables
`java.lang.String`	`toString()` Equivalent to `asList().toString()`
`ParallelArrayWithBounds`	`withBounds(int firstIndex, int upperBound)` Returns an operation prefix that causes a method to operate only on the elements of the array between firstIndex (inclusive) and upperBound (exclusive).
`ParallelArrayWithFilter`	`withFilter(Predicate selector)` Returns an operation prefix that causes a method to operate only on the elements of the array for which the given selector returns true
`ParallelArrayWithFilter`	`withFilter(BinaryPredicate selector, ParallelArrayWithMapping other)` Returns an operation prefix that causes a method to operate only on elements for which the given binary selector returns true
`ParallelArrayWithFilter`	`withIndexedFilter(IntAndObjectPredicate selector)` Returns an operation prefix that causes a method to operate only on elements for which the given indexed selector returns true
`ParallelArrayWithMapping`	`withIndexedMapping(IntAndObjectToObject mapper)` Returns an operation prefix that causes a method to operate on mappings of this array using the given mapper that accepts as arguments an element's current index and value, and produces a new value.
`ParallelArrayWithDoubleMapping`	`withIndexedMapping(IntAndObjectToDouble mapper)` Returns an operation prefix that causes a method to operate on mappings of this array using the given mapper that accepts as arguments an element's current index and value, and produces a new value.
`ParallelArrayWithLongMapping`	`withIndexedMapping(IntAndObjectToLong mapper)` Returns an operation prefix that causes a method to operate on mappings of this array using the given mapper that accepts as arguments an element's current index and value, and produces a new value.
`ParallelArrayWithMapping`	`withMapping(Op op)` Returns an operation prefix that causes a method to operate on mapped elements of the array using the given op.
`ParallelArrayWithDoubleMapping`	`withMapping(ObjectToDouble op)` Returns an operation prefix that causes a method to operate on mapped elements of the array using the given op.
`ParallelArrayWithLongMapping`	`withMapping(ObjectToLong op)` Returns an operation prefix that causes a method to operate on mapped elements of the array using the given op.
`ParallelArrayWithMapping`	`withMapping(BinaryOp combiner, ParallelArrayWithMapping other)` Returns an operation prefix that causes a method to operate on binary mappings of this array and the other array.
`ParallelArrayWithMapping`	`withMapping(ObjectAndDoubleToObject combiner, ParallelDoubleArrayWithDoubleMapping other)` Returns an operation prefix that causes a method to operate on binary mappings of this array and the other array.
`ParallelArrayWithMapping`	`withMapping(ObjectAndLongToObject combiner, ParallelLongArrayWithLongMapping other)` Returns an operation prefix that causes a method to operate on binary mappings of this array and the other array.
`ParallelArrayWithDoubleMapping`	`withMapping(ObjectAndObjectToDouble combiner, ParallelArrayWithMapping other)` Returns an operation prefix that causes a method to operate on binary mappings of this array and the other array.
`ParallelArrayWithDoubleMapping`	`withMapping(ObjectAndDoubleToDouble combiner, ParallelDoubleArrayWithDoubleMapping other)` Returns an operation prefix that causes a method to operate on binary mappings of this array and the other array.
`ParallelArrayWithDoubleMapping`	`withMapping(ObjectAndLongToDouble combiner, ParallelLongArrayWithLongMapping other)` Returns an operation prefix that causes a method to operate on binary mappings of this array and the other array.
`ParallelArrayWithLongMapping`	`withMapping(ObjectAndObjectToLong combiner, ParallelArrayWithMapping other)` Returns an operation prefix that causes a method to operate on binary mappings of this array and the other array.
`ParallelArrayWithLongMapping`	`withMapping(ObjectAndDoubleToLong combiner, ParallelDoubleArrayWithDoubleMapping other)` Returns an operation prefix that causes a method to operate on binary mappings of this array and the other array.
`ParallelArrayWithLongMapping`	`withMapping(ObjectAndLongToLong combiner, ParallelLongArrayWithLongMapping other)` Returns an operation prefix that causes a method to operate on binary mappings of this array and the other array.

Field Detail

listView

ParallelArray.AsList listView

Lazily constructed list view

Constructor Detail

ParallelArray

protected ParallelArray(ForkJoinPool executor, java.lang.Object[] array, int limit)

Constructor for use by subclasses to create a new ParallelArray using the given executor, and initially using the supplied array, with effective size bound by the given limit. This constructor is designed to enable extensions via subclassing. To create a ParallelArray, use create, createEmpty, createUsingHandoff or createFromCopy.

Parameters:: executor - the executor; array - the array; limit - the upper bound limit

ParallelArray

ParallelArray(ForkJoinPool executor, java.lang.Object[] array)

Trusted internal version of protected constructor.

Method Detail

addAll

public ParallelArray addAll(java.lang.Object[] other)

Equivalent to asList().addAll but specialized for array arguments and likely to be more efficient.

Parameters:: other - the elements to add

Returns:: this (to simplify use in expressions)

addAll

public ParallelArray addAll(ParallelArrayWithMapping other)

Appends all (possibly bounded, filtered, or mapped) elements of the given ParallelArray, resizing and/or reallocating this array if necessary.

Parameters:: other - the elements to add

Returns:: this (to simplify use in expressions)

all

public ParallelArray all()

Returns a new ParallelArray holding all elements

Returns:: a new ParallelArray holding all elements

all

public ParallelArray all(java.lang.Class elementType)

Returns a new ParallelArray with the given element type holding all elements

Parameters:: elementType - the type of the elements

Returns:: a new ParallelArray holding all elements

allNonidenticalElements

public ParallelArray allNonidenticalElements()

Returns a new ParallelArray containing only the non-null unique elements of this array (that is, without any duplicates), using reference identity to test for duplication.

Returns:: the new ParallelArray

allUniqueElements

public ParallelArray allUniqueElements()

Returns a new ParallelArray containing only the non-null unique elements of this array (that is, without any duplicates), using each element's equals method to test for duplication.

Returns:: the new ParallelArray

appendElement

final void appendElement(java.lang.Object e)

apply

public void apply(Procedure procedure)

Applies the given procedure to elements

Parameters:: procedure - the procedure

asList

public java.util.List asList()

Returns a view of this ParallelArray as a List. This List has the same structural and performance characteristics as java.util.ArrayList, and may be used to modify, replace or extend the bounds of the array underlying this ParallelArray. The methods supported by this list view are not in general implemented as parallel operations. This list is also not itself thread-safe. In particular, performing list updates while other parallel operations are in progress has undefined (and surely undesired) effects.

Returns:: a list view

binarySearch

public int binarySearch(java.lang.Object target)

Assuming this array is sorted, returns the index of an element equal to given target, or -1 if not present. If the array is not sorted, the results are undefined.

Parameters:: target - the element to search for

Returns:: the index or -1 if not present

binarySearch

public int binarySearch(java.lang.Object target, java.util.Comparator comparator)

Assuming this array is sorted with respect to the given comparator, returns the index of an element equal to given target, or -1 if not present. If the array is not sorted, the results are undefined.

Parameters:: target - the element to search for; comparator - the comparator

Returns:: the index or -1 if not present

create

public static ParallelArray create(int size, java.lang.Class elementType, ForkJoinPool executor)

Creates a new ParallelArray using the given executor and an array of the given size constructed using the indicated base element type.

Parameters:: size - the array size; elementType - the type of the elements; executor - the executor

createEmpty

public static ParallelArray createEmpty(int size, java.lang.Class elementType, ForkJoinPool executor)

Creates a new ParallelArray using the given executor and an array of the given size constructed using the indicated base element type, but with an initial effective size of zero, enabling incremental insertion via ParallelArray#asList#asList operations.

Parameters:: size - the array size; elementType - the type of the elements; executor - the executor

createFromCopy

public static ParallelArray createFromCopy(java.lang.Object[] source, ForkJoinPool executor)

Creates a new ParallelArray using the given executor and initially holding copies of the given source elements.

Parameters:: source - the source of initial elements; executor - the executor

createFromCopy

public static ParallelArray createFromCopy(int size, java.lang.Object[] source, ForkJoinPool executor)

Creates a new ParallelArray using an array of the given size, initially holding copies of the given source truncated or padded with nulls to obtain the specified length.

Parameters:: source - the source of initial elements; size - the array size; executor - the executor

createUsingHandoff

public static ParallelArray createUsingHandoff(java.lang.Object[] handoff, ForkJoinPool executor)

Creates a new ParallelArray initially using the given array and executor. In general, the handed off array should not be used for other purposes once constructing this ParallelArray. The given array may be internally replaced by another array in the course of methods that add or remove elements.

Parameters:: handoff - the array; executor - the executor

cumulate

public ParallelArray cumulate(Reducer reducer, java.lang.Object base)

Replaces each element with the running cumulation of applying the given reducer. For example, if the contents are the numbers 1, 2, 3, and the reducer operation adds numbers, then after invocation of this method, the contents would be 1, 3, 6 (that is, 1, 1+2, 1+2+3);

Parameters:: reducer - the reducer; base - the result for an empty array

Returns:: this (to simplify use in expressions)

defaultExecutor

public static ForkJoinPool defaultExecutor()

Returns a common default executor for use in ParallelArrays. This executor arranges enough parallelism to use most, but not necessarily all, of the available processors on this system.

Returns:: the executor

get

public java.lang.Object get(int i)

Returns the element of the array at the given index

Parameters:: i - the index

Returns:: the element of the array at the given index

getArray

public java.lang.Object[] getArray()

Returns the underlying array used for computations

Returns:: the array

getExecutor

public ForkJoinPool getExecutor()

Returns the executor used for computations.

Returns:: the executor

hasAllEqualElements

public boolean hasAllEqualElements(ParallelArrayWithMapping other)

Returns true if all elements at the same relative positions of this and other array are equal.

Parameters:: other - the other array

Returns:: true if equal

hasAllIdenticalElements

public boolean hasAllIdenticalElements(ParallelArrayWithMapping other)

Returns true if all elements at the same relative positions of this and other array are identical.

Parameters:: other - the other array

Returns:: true if equal

indexOf

public int indexOf(java.lang.Object target)

Returns the index of some element equal to given target, or -1 if not present

Parameters:: target - the element to search for

Returns:: the index or -1 if not present

insertElementAt

final void insertElementAt(int index, java.lang.Object e)

insertSlotsAt

final void insertSlotsAt(int index, int len)

Makes len slots available at index.

iterator

public java.util.Iterator iterator()

Returns an iterator stepping through each element of the array up to the current limit. This iterator does not support the remove operation. However, a full ListIterator supporting add, remove, and set operations is available via asList.

Returns:: an iterator stepping through each element.

max

public java.lang.Object max(java.util.Comparator comparator)

Returns the maximum element, or null if empty

Parameters:: comparator - the comparator

Returns:: maximum element, or null if empty

max

public java.lang.Object max()

Returns the maximum element, or null if empty assuming that all elements are Comparables

throws:: ClassCastException if any element is not Comparable.

Returns:: maximum element, or null if empty

min

public java.lang.Object min(java.util.Comparator comparator)

Returns the minimum element, or null if empty

Parameters:: comparator - the comparator

Returns:: minimum element, or null if empty

min

public java.lang.Object min()

Returns the minimum element, or null if empty, assuming that all elements are Comparables

throws:: ClassCastException if any element is not Comparable.

Returns:: minimum element, or null if empty

precumulate

public java.lang.Object precumulate(Reducer reducer, java.lang.Object base)

Replaces each element with the cumulation of applying the given reducer to all previous values, and returns the total reduction. For example, if the contents are the numbers 1, 2, 3, and the reducer operation adds numbers, then after invocation of this method, the contents would be 0, 1, 3 (that is, 0, 0+1, 0+1+2, and the return value would be 6 (that is, 1+2+3);

Parameters:: reducer - the reducer; base - the result for an empty array

Returns:: the total reduction

reduce

public java.lang.Object reduce(Reducer reducer, java.lang.Object base)

Returns reduction of elements

Parameters:: reducer - the reducer; base - the result for an empty array

Returns:: reduction

removeAll

public ParallelArray removeAll(Predicate selector)

Removes from the array all elements for which the given selector holds.

Parameters:: selector - the selector

Returns:: this (to simplify use in expressions)

removeConsecutiveDuplicates

public ParallelArray removeConsecutiveDuplicates()

Removes consecutive elements that are equal (or null), shifting others leftward, and possibly decreasing size. This method may be used after sorting to ensure that this ParallelArray contains a set of unique elements.

Returns:: this (to simplify use in expressions)

removeNulls

public ParallelArray removeNulls()

Removes null elements, shifting others leftward, and possibly decreasing size.

Returns:: this (to simplify use in expressions)

removeSlotAt

final void removeSlotAt(int index)

removeSlotsAt

final void removeSlotsAt(int fromIndex, int toIndex)

replaceElementsWith

final void replaceElementsWith(java.lang.Object[] a)

replaceWithGeneratedValue

public ParallelArray replaceWithGeneratedValue(Generator generator)

Replaces elements with the results of applying the given generator.

Parameters:: generator - the generator

Returns:: this (to simplify use in expressions)

replaceWithMappedIndex

public ParallelArray replaceWithMappedIndex(IntToObject op)

Replaces elements with the results of applying the given mapping to their indices.

Parameters:: op - the op

Returns:: this (to simplify use in expressions)

replaceWithMappedIndex

public ParallelArray replaceWithMappedIndex(IntAndObjectToObject op)

Replaces elements with the results of applying the given mapping to each index and current element value

Parameters:: op - the op

Returns:: this (to simplify use in expressions)

replaceWithMapping

public ParallelArray replaceWithMapping(Op op)

Replaces elements with the results of applying the given transform to their current values.

Parameters:: op - the op

Returns:: this (to simplify use in expressions)

replaceWithMapping

public ParallelArray replaceWithMapping(BinaryOp combiner, ParallelArrayWithMapping other)

Replaces elements with results of applying op(thisElement, otherElement)

Parameters:: other - the other array; combiner - the combiner

Returns:: this (to simplify use in expressions)

replaceWithMapping

public ParallelArray replaceWithMapping(BinaryOp combiner, java.lang.Object[] other)

Replaces elements with results of applying op(thisElement, otherElement)

Parameters:: other - the other array; combiner - the combiner

Returns:: this (to simplify use in expressions)

replaceWithValue

public ParallelArray replaceWithValue(java.lang.Object value)

Replaces elements with the given value.

Parameters:: value - the value

Returns:: this (to simplify use in expressions)

resizeArray

final void resizeArray(int newCap)

seqIndexOf

final int seqIndexOf(java.lang.Object target)

seqLastIndexOf

final int seqLastIndexOf(java.lang.Object target)

set

public void set(int i, java.lang.Object x)

Sets the element of the array at the given index to the given value

Parameters:: i - the index; x - the value

setLimit

public final void setLimit(int newLimit)

Ensures that the underlying array can be accessed up to the given upper bound, reallocating and copying the underlying array to expand if necessary. Or, if the given limit is less than the length of the underlying array, causes computations to ignore elements past the given limit.

throws:: IllegalArgumentException if newLimit less than zero.

Parameters:: newLimit - the new upper bound

size

public int size()

Returns the effective size of the underlying array. The effective size is the current limit, if used (see setLimit), or the length of the array otherwise.

Returns:: the effective size of array

sort

public ParallelArray sort(java.util.Comparator comparator)

Sorts the array. Unlike Arrays.sort, this sort does not guarantee that elements with equal keys maintain their relative position in the array.

Parameters:: comparator - the comparator to use

Returns:: this (to simplify use in expressions)

sort

public ParallelArray sort()

Sorts the array, assuming all elements are Comparable. Unlike Arrays.sort, this sort does not guarantee that elements with equal keys maintain their relative position in the array.

throws:: ClassCastException if any element is not Comparable.

Returns:: this (to simplify use in expressions)

summary

public SummaryStatistics summary(java.util.Comparator comparator)

Returns summary statistics, using the given comparator to locate minimum and maximum elements.

Parameters:: comparator - the comparator to use for locating minimum and maximum elements

Returns:: the summary.

summary

public SummaryStatistics summary()

Returns summary statistics, assuming that all elements are Comparables

Returns:: the summary.

toString

public java.lang.String toString()

Equivalent to asList().toString()

Returns:: a string representation

withBounds

public ParallelArrayWithBounds withBounds(int firstIndex, int upperBound)

Returns an operation prefix that causes a method to operate only on the elements of the array between firstIndex (inclusive) and upperBound (exclusive).

Parameters:: firstIndex - the lower bound (inclusive); upperBound - the upper bound (exclusive)

Returns:: operation prefix

withFilter

public ParallelArrayWithFilter withFilter(Predicate selector)

Returns an operation prefix that causes a method to operate only on the elements of the array for which the given selector returns true

Parameters:: selector - the selector

Returns:: operation prefix

withFilter

public ParallelArrayWithFilter withFilter(BinaryPredicate selector, ParallelArrayWithMapping other)

Returns an operation prefix that causes a method to operate only on elements for which the given binary selector returns true

Parameters:: selector - the selector

Returns:: operation prefix

withIndexedFilter

public ParallelArrayWithFilter withIndexedFilter(IntAndObjectPredicate selector)

Returns an operation prefix that causes a method to operate only on elements for which the given indexed selector returns true

Parameters:: selector - the selector

Returns:: operation prefix

withIndexedMapping

public ParallelArrayWithMapping withIndexedMapping(IntAndObjectToObject mapper)

Returns an operation prefix that causes a method to operate on mappings of this array using the given mapper that accepts as arguments an element's current index and value, and produces a new value. Index-based mappings allow parallel computation of many common array operations. For example, you could create function to average the values at the same index of multiple arrays and apply it using this method.

Parameters:: mapper - the mapper

Returns:: operation prefix

withIndexedMapping

public ParallelArrayWithDoubleMapping withIndexedMapping(IntAndObjectToDouble mapper)

Returns an operation prefix that causes a method to operate on mappings of this array using the given mapper that accepts as arguments an element's current index and value, and produces a new value.

Parameters:: mapper - the mapper

Returns:: operation prefix

withIndexedMapping

public ParallelArrayWithLongMapping withIndexedMapping(IntAndObjectToLong mapper)

Returns an operation prefix that causes a method to operate on mappings of this array using the given mapper that accepts as arguments an element's current index and value, and produces a new value.

Parameters:: mapper - the mapper

Returns:: operation prefix

withMapping

public ParallelArrayWithMapping withMapping(Op op)

Returns an operation prefix that causes a method to operate on mapped elements of the array using the given op.

Parameters:: op - the op

Returns:: operation prefix

withMapping

public ParallelArrayWithDoubleMapping withMapping(ObjectToDouble op)

Returns an operation prefix that causes a method to operate on mapped elements of the array using the given op.

Parameters:: op - the op

Returns:: operation prefix

withMapping

public ParallelArrayWithLongMapping withMapping(ObjectToLong op)

Returns an operation prefix that causes a method to operate on mapped elements of the array using the given op.

Parameters:: op - the op

Returns:: operation prefix