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dl |
1.1 |
/* |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain, as explained at |
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jsr166 |
1.5 |
* http://creativecommons.org/publicdomain/zero/1.0/ |
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dl |
1.1 |
*/ |
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import jsr166y.*; |
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import extra166y.*; |
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import java.util.*; |
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class ParallelArraySortDemo { |
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static final Random rng = new Random(); |
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static final long NPS = (1000L * 1000 * 1000); |
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jsr166 |
1.3 |
public static void main(String[] args) throws Exception { |
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dl |
1.1 |
int n = 1 << 20; |
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int reps = 9; |
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System.out.printf("Sorting %d Longs, %d replications\n", n, reps); |
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Long[] a = new Long[n]; |
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randomFill(a); |
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for (int i = 0; i < reps; ++i) { |
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long last = System.nanoTime(); |
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java.util.Arrays.sort(a); |
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double elapsed = (double)(System.nanoTime() - last) / NPS; |
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System.out.printf("java.util.Arrays.sort time: %7.3f\n", elapsed); |
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checkSorted(a); |
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shuffle(a); |
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// System.gc(); |
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} |
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ForkJoinPool fjpool = new ForkJoinPool(); |
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ParallelArray<Long> pa = ParallelArray.createUsingHandoff(a, fjpool); |
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for (int i = 0; i < reps; ++i) { |
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long last = System.nanoTime(); |
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pa.sort(); |
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double elapsed = (double)(System.nanoTime() - last) / NPS; |
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System.out.printf("ArrayTasks.sort time: %7.3f\n", elapsed); |
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checkSorted(a); |
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shuffle(a); |
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// System.gc(); |
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} |
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fjpool.shutdown(); |
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} |
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jsr166 |
1.4 |
static void checkSorted(Long[] a) { |
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dl |
1.1 |
int n = a.length; |
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for (int i = 0; i < n - 1; i++) { |
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if (a[i].compareTo(a[i+1]) > 0) { |
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throw new Error("Unsorted at " + i + ": " + a[i] + " / " + a[i+1]); |
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} |
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} |
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} |
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jsr166 |
1.2 |
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dl |
1.1 |
static void randomFill(Long[] a) { |
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for (int i = 0; i < a.length; ++i) |
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a[i] = new Long(rng.nextLong()); |
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} |
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jsr166 |
1.2 |
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dl |
1.1 |
static void shuffle(Long[] a) { |
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int n = a.length; |
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for (int i = n; i > 1; --i) { |
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int r = rng.nextInt(i); |
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Long t = a[i-1]; |
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a[i-1] = a[r]; |
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a[r] = t; |
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} |
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} |
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} |
