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*/ |
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package java.util; |
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import java.util.concurrent.ForkJoinPool; |
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import java.util.concurrent.CountedCompleter; |
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import java.util.function.BinaryOperator; |
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import java.util.function.DoubleBinaryOperator; |
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import java.util.function.IntBinaryOperator; |
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import java.util.function.LongBinaryOperator; |
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import java.util.function.DoubleBinaryOperator; |
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/** |
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* ForkJoin tasks to perform Arrays.parallelPrefix operations. |
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* @since 1.8 |
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*/ |
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class ArrayPrefixHelpers { |
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private ArrayPrefixHelpers() {}; // non-instantiable |
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private ArrayPrefixHelpers() {} // non-instantiable |
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/* |
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* Parallel prefix (aka cumulate, scan) task classes |
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/** The smallest subtask array partition size to use as threshold */ |
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static final int MIN_PARTITION = 16; |
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static final class CumulateTask<T> extends CountedCompleter<Void> { |
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private static final class CumulateTask<T> |
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extends CountedCompleter<Void> { |
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final T[] array; |
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final BinaryOperator<T> function; |
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CumulateTask<T> left, right; |
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T in, out; |
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final int lo, hi, origin, fence, threshold; |
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/** Root task constructor */ |
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public CumulateTask(CumulateTask<T> parent, |
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BinaryOperator<T> function, |
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T[] array, int lo, int hi) { |
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super(parent); |
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this.function = function; this.array = array; |
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this.lo = this.origin = lo; this.hi = this.fence = hi; |
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int p; |
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this.threshold = |
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(p = (hi - lo) / (ForkJoinPool.getCommonPoolParallelism() << 3)) |
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<= MIN_PARTITION ? MIN_PARTITION : p; |
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} |
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/** Subtask constructor */ |
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CumulateTask(CumulateTask<T> parent, BinaryOperator<T> function, |
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T[] array, int origin, int fence, int threshold, |
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int lo, int hi) { |
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private static final long serialVersionUID = 5293554502939613543L; |
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} |
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static final class LongCumulateTask extends CountedCompleter<Void> { |
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private static final class LongCumulateTask |
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extends CountedCompleter<Void> { |
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final long[] array; |
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final LongBinaryOperator function; |
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LongCumulateTask left, right; |
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long in, out; |
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final int lo, hi, origin, fence, threshold; |
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/** Root task constructor */ |
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public LongCumulateTask(LongCumulateTask parent, |
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LongBinaryOperator function, |
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long[] array, int lo, int hi) { |
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super(parent); |
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this.function = function; this.array = array; |
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this.lo = this.origin = lo; this.hi = this.fence = hi; |
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int p; |
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this.threshold = |
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(p = (hi - lo) / (ForkJoinPool.getCommonPoolParallelism() << 3)) |
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<= MIN_PARTITION ? MIN_PARTITION : p; |
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} |
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/** Subtask constructor */ |
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LongCumulateTask(LongCumulateTask parent, LongBinaryOperator function, |
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long[] array, int origin, int fence, int threshold, |
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int lo, int hi) { |
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private static final long serialVersionUID = -5074099945909284273L; |
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} |
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static final class DoubleCumulateTask extends CountedCompleter<Void> { |
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private static final class DoubleCumulateTask |
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extends CountedCompleter<Void> { |
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final double[] array; |
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final DoubleBinaryOperator function; |
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DoubleCumulateTask left, right; |
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double in, out; |
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final int lo, hi, origin, fence, threshold; |
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/** Root task constructor */ |
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public DoubleCumulateTask(DoubleCumulateTask parent, |
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DoubleBinaryOperator function, |
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double[] array, int lo, int hi) { |
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super(parent); |
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this.function = function; this.array = array; |
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this.lo = this.origin = lo; this.hi = this.fence = hi; |
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int p; |
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this.threshold = |
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(p = (hi - lo) / (ForkJoinPool.getCommonPoolParallelism() << 3)) |
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<= MIN_PARTITION ? MIN_PARTITION : p; |
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} |
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/** Subtask constructor */ |
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DoubleCumulateTask(DoubleCumulateTask parent, DoubleBinaryOperator function, |
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double[] array, int origin, int fence, int threshold, |
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int lo, int hi) { |
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double[] array, int origin, int fence, int threshold, |
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int lo, int hi) { |
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super(parent); |
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this.function = function; this.array = array; |
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this.origin = origin; this.fence = fence; |
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private static final long serialVersionUID = -586947823794232033L; |
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} |
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static final class IntCumulateTask extends CountedCompleter<Void> { |
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private static final class IntCumulateTask |
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extends CountedCompleter<Void> { |
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final int[] array; |
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final IntBinaryOperator function; |
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IntCumulateTask left, right; |
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int in, out; |
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final int lo, hi, origin, fence, threshold; |
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/** Root task constructor */ |
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public IntCumulateTask(IntCumulateTask parent, |
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IntBinaryOperator function, |
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int[] array, int lo, int hi) { |
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super(parent); |
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this.function = function; this.array = array; |
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this.lo = this.origin = lo; this.hi = this.fence = hi; |
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int p; |
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this.threshold = |
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(p = (hi - lo) / (ForkJoinPool.getCommonPoolParallelism() << 3)) |
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<= MIN_PARTITION ? MIN_PARTITION : p; |
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} |
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/** Subtask constructor */ |
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IntCumulateTask(IntCumulateTask parent, IntBinaryOperator function, |
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int[] array, int origin, int fence, int threshold, |
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int lo, int hi) { |
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int[] array, int origin, int fence, int threshold, |
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int lo, int hi) { |
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super(parent); |
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this.function = function; this.array = array; |
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this.origin = origin; this.fence = fence; |