jsr166z.forkjoin
Class ParallelDoubleArray

java.lang.Object
  jsr166z.forkjoin.ParallelDoubleArray

public class ParallelDoubleArray
extends java.lang.Object

An array of doubles supporting parallel operations. This class provides methods supporting the same operations as ParallelArray, but specialized for scalar doubles. It additionally provides a few methods specific to numerical values.

Nested Class Summary

static class	ParallelDoubleArray.WithBounds A restriction of parallel array operations to apply only within a given range of indices.
static class	ParallelDoubleArray.WithDoubleMapping A modifier for parallel array operations to apply to mappings of elements to doubles, not to the elements themselves
static class	ParallelDoubleArray.WithFilter A restriction of parallel array operations to apply only to elements for which a selector returns true
static class	ParallelDoubleArray.WithIntMapping A modifier for parallel array operations to apply to mappings of elements to ints, not to the elements themselves
static class	ParallelDoubleArray.WithLongMapping A modifier for parallel array operations to apply to mappings of elements to longs, not to the elements themselves
static class	ParallelDoubleArray.WithMapping<U> A modifier for parallel array operations to apply to mappings of elements, not to the elements themselves

Constructor Summary

ParallelDoubleArray(ForkJoinExecutor executor, double[] handoff)
Creates a new ParallelDoubleArray using the given executor and array.

ParallelDoubleArray(ForkJoinExecutor executor, int size)
Creates a new ParallelDoubleArray using the given executor and an array of the given size.

ParallelDoubleArray(ForkJoinExecutor executor, int size, double[] sourceToCopy)
Creates a new ParallelDoubleArray using the given executor and an array of the given size, initially holding copies of the given source truncated or padded with zero to obtain the specified length.

Method Summary

void	apply({double=>void} procedure) Applies the given procedure to elements
ParallelDoubleArray	combine(double[] other, {double,double=>double} combiner) Returns a ParallelArray containing results of applying combine(thisElement, otherElement) for each element.
ParallelDoubleArray	combine(ParallelDoubleArray other, {double,double=>double} combiner) Returns a ParallelArray containing results of applying combine(thisElement, otherElement) for each element.
void	cumulate({double,double=>double} reducer, double base) Replaces each element with the running cumulation of applying the given reducer.
void	cumulateSum() Replaces each element with the running sum
double	get(int i) Returns the element of the array at the given index
double[]	getArray() Returns the underlying array used for computations
ForkJoinExecutor	getExecutor() Returns the executor used for computations
int	indexOfMax() Returns the index of the greatest element , or -1 if empty assuming that all elements are Comparables
int	indexOfMax({double,double=>int} comparator) Returns the index of the greatest element , or -1 if empty
int	indexOfMin() Returns the index of the least element , or -1 if empty assuming that all elements are Comparables
int	indexOfMin({double,double=>int} comparator) Returns the index of the least element , or -1 if empty
double	max() Returns the maximum element, or -Double.MAX_VALUE if empty assuming that all elements are Comparables
double	max({double,double=>int} comparator) Returns the maximum element, or -Double.MAX_VALUE if empty
double	min() Returns the minimum element, or Double.MAX_VALUE if empty, assuming that all elements are Comparables
double	min({double,double=>int} comparator) Returns the minimum element, or Double.MAX_VALUE if empty
ParallelDoubleArray	newArray() Returns a new ParallelArray holding elements
double	precumulate({double,double=>double} reducer, double base) Replaces each element with the cumulation of applying the given reducer to all previous values, and returns the total reduction.
double	precumulateSum() Replaces each element with its prefix sum
void	randomFill() Sets each element to a uniform random value having the same properties as Random.nextDouble()
double	reduce({double,double=>double} reducer, double base) Returns reduction of elements
void	replaceWithCombination(double[] other, {double,double=>double} combiner) Replaces elements with results of applying combine(thisElement, otherElement)
void	replaceWithCombination(ParallelDoubleArray other, {double,double=>double} combiner) Replaces elements with results of applying combine(thisElement, otherElement)
void	replaceWithGeneratedValue({=>double} generator) Replaces elements with the results of applying the given generator.
void	replaceWithMappedIndex({int=>double} mapper) Replaces elements with the results of applying the given mapper to their indices.
void	replaceWithTransform({double=>double} mapper) Replaces elements with the results of applying the given mapper to their current values.
void	replaceWithValue(double value) Replaces elements with the given value.
void	set(int i, double x) Sets the element of the array at the given index to the given value
int	size() Returns the length of the underlying array
void	sort() Sorts the array, using natural comparator.
void	sort({double,double=>int} comparator) Sorts the array
double	sum() Returns the sum of elements
ParallelDoubleArray.WithBounds	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).
ParallelDoubleArray.WithFilter	withFilter({double=>boolean} 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
ParallelDoubleArray.WithDoubleMapping	withMapping({double=>double} mapper) Returns an operation prefix that causes a method to operate on mapped elements of the array using the given mapper.
ParallelDoubleArray.WithIntMapping	withMapping({double=>int} mapper) Returns an operation prefix that causes a method to operate on mapped elements of the array using the given mapper.
ParallelDoubleArray.WithLongMapping	withMapping({double=>long} mapper) Returns an operation prefix that causes a method to operate on mapped elements of the array using the given mapper.
<U> ParallelDoubleArray.WithMapping<U>	withMapping({double=>U} mapper) Returns an operation prefix that causes a method to operate on mapped elements of the array using the given mapper.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ParallelDoubleArray

public ParallelDoubleArray(ForkJoinExecutor executor,
                           double[] handoff)

Creates a new ParallelDoubleArray using the given executor and array. In general, the handed off array should not be used for other purposes once constructing this ParallelDoubleArray.

Parameters:

executor - the executor

handoff - the array

ParallelDoubleArray

public ParallelDoubleArray(ForkJoinExecutor executor,
                           int size,
                           double[] sourceToCopy)

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

Parameters:

executor - the executor

size - the array size

sourceToCopy - the source of initial elements

ParallelDoubleArray

public ParallelDoubleArray(ForkJoinExecutor executor,
                           int size)

Creates a new ParallelDoubleArray using the given executor and an array of the given size.

Parameters:

executor - the executor

size - the array size

Method Detail

getExecutor

public ForkJoinExecutor getExecutor()

Returns the executor used for computations

Returns:

the executor

getArray

public double[] getArray()

Returns the underlying array used for computations

Returns:

the array

size

public int size()

Returns the length of the underlying array

Returns:

the length of the underlying array

get

public double 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

set

public void set(int i,
                double x)

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

Parameters:

i - the index

x - the value

apply

public void apply({double=>void} procedure)

Applies the given procedure to elements

Parameters:

procedure - the procedure

reduce

public double reduce({double,double=>double} reducer,
                     double base)

Returns reduction of elements

Parameters:

reducer - the reducer

base - the result for an empty array

Returns:

reduction

newArray

public ParallelDoubleArray newArray()

Returns a new ParallelArray holding elements

Returns:

a new ParallelArray holding elements

combine

public ParallelDoubleArray combine(double[] other,
                                   {double,double=>double} combiner)

Returns a ParallelArray containing results of applying combine(thisElement, otherElement) for each element.

Parameters:

other - the other array

combiner - the combiner

Returns:

the array of mappings

Throws:

java.lang.ArrayIndexOutOfBoundsException - if other array is shorter than this array.

combine

public ParallelDoubleArray combine(ParallelDoubleArray other,
                                   {double,double=>double} combiner)

Returns a ParallelArray containing results of applying combine(thisElement, otherElement) for each element.

Parameters:

other - the other array

combiner - the combiner

Returns:

the array of mappings

Throws:

java.lang.ArrayIndexOutOfBoundsException - if other array is not the same length as this array.

replaceWithTransform

public void replaceWithTransform({double=>double} mapper)

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

Parameters:

mapper - the mapper

replaceWithMappedIndex

public void replaceWithMappedIndex({int=>double} mapper)

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

Parameters:

mapper - the mapper

replaceWithGeneratedValue

public void replaceWithGeneratedValue({=>double} generator)

Replaces elements with the results of applying the given generator.

Parameters:

generator - the generator

randomFill

public void randomFill()

Sets each element to a uniform random value having the same properties as Random.nextDouble()

replaceWithValue

public void replaceWithValue(double value)

Replaces elements with the given value.

Parameters:

value - the value

replaceWithCombination

public void replaceWithCombination(ParallelDoubleArray other,
                                   {double,double=>double} combiner)

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

Parameters:

other - the other array

combiner - the combiner

Throws:

java.lang.ArrayIndexOutOfBoundsException - if other array has fewer elements than this array.

replaceWithCombination

public void replaceWithCombination(double[] other,
                                   {double,double=>double} combiner)

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

Parameters:

other - the other array

combiner - the combiner

Throws:

java.lang.ArrayIndexOutOfBoundsException - if other array has fewer elements than this array.

indexOfMin

public int indexOfMin({double,double=>int} comparator)

Returns the index of the least element , or -1 if empty

Parameters:

comparator - the comparator

Returns:

the index of least element or -1 if empty.

indexOfMax

public int indexOfMax({double,double=>int} comparator)

Returns the index of the greatest element , or -1 if empty

Parameters:

comparator - the comparator

Returns:

the index of greatest element or -1 if empty.

indexOfMin

public int indexOfMin()

Returns the index of the least element , or -1 if empty assuming that all elements are Comparables

Returns:

the index of least element or -1 if empty.

indexOfMax

public int indexOfMax()

Returns the index of the greatest element , or -1 if empty assuming that all elements are Comparables

Returns:

the index of greatest element or -1 if empty.

min

public double min({double,double=>int} comparator)

Returns the minimum element, or Double.MAX_VALUE if empty

Parameters:

comparator - the comparator

Returns:

minimum element, or Double.MAX_VALUE if empty

min

public double min()

Returns the minimum element, or Double.MAX_VALUE if empty, assuming that all elements are Comparables

Returns:

minimum element, or Double.MAX_VALUE if empty

max

public double max({double,double=>int} comparator)

Returns the maximum element, or -Double.MAX_VALUE if empty

Parameters:

comparator - the comparator

Returns:

maximum element, or -Double.MAX_VALUE if empty

max

public double max()

Returns the maximum element, or -Double.MAX_VALUE if empty assuming that all elements are Comparables

Returns:

maximum element, or -Double.MAX_VALUE if empty

sum

public double sum()

Returns the sum of elements

Returns:

the sum of elements

cumulate

public void cumulate({double,double=>double} reducer,
                     double 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

precumulate

public double precumulate({double,double=>double} reducer,
                          double 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

cumulateSum

public void cumulateSum()

Replaces each element with the running sum

precumulateSum

public double precumulateSum()

Replaces each element with its prefix sum

Returns:

the total sum

sort

public void sort({double,double=>int} comparator)

Sorts the array

Parameters:

comparator - the comparator to use

sort

public void sort()

Sorts the array, using natural comparator.

withBounds

public ParallelDoubleArray.WithBounds 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 ParallelDoubleArray.WithFilter withFilter({double=>boolean} 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

withMapping

public <U> ParallelDoubleArray.WithMapping<U> withMapping({double=>U} mapper)

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

Parameters:

mapper - the mapper

Returns:

operation prefix

withMapping

public ParallelDoubleArray.WithDoubleMapping withMapping({double=>double} mapper)

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

Parameters:

mapper - the mapper

Returns:

operation prefix

withMapping

public ParallelDoubleArray.WithLongMapping withMapping({double=>long} mapper)

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

Parameters:

mapper - the mapper

Returns:

operation prefix

withMapping

public ParallelDoubleArray.WithIntMapping withMapping({double=>int} mapper)

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

Parameters:

mapper - the mapper

Returns:

operation prefix