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/* |
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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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* http://creativecommons.org/licenses/publicdomain |
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* http://creativecommons.org/publicdomain/zero/1.0/ |
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*/ |
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//import jsr166y.*; |
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import java.util.concurrent.*; |
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/** |
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* Sample program using Gaussian Quadrature for numerical integration. |
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* Sample program using Guassian Quadrature for numerical integration. |
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* This version uses a simplified hardwired function. Inspired by a |
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* <A href="http://www.cs.uga.edu/~dkl/filaments/dist.html"> |
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* Filaments</A> demo program. |
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* |
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*/ |
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public final class Integrate { |
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static int forkPolicy = DYNAMIC; |
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static String forkArg = "dynamic"; |
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// the function to integrate |
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static double computeFunction(double x) { |
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/** the function to integrate */ |
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static double computeFunction(double x) { |
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return (x * x + 1.0) * x; |
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} |
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static final double start = 0.0; |
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static final double end = 1536.0; |
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/* |
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/** |
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* The number of recursive calls for |
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* integrate from start to end. |
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* (Empirically determined) |
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static final int calls = 263479047; |
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public static void main(String[] args) throws Exception { |
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int procs = Runtime.getRuntime().availableProcessors(); |
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int procs = 0; |
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try { |
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if (args.length > 0) |
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System.out.println("Usage: java Integrate3 threads <s[erial] | d[ynamic] | f[ork] - default d>"); |
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return; |
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} |
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oneTest(procs); |
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oneTest(procs); |
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oneTest(procs); |
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} |
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ForkJoinPool g = new ForkJoinPool(procs); |
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static void oneTest(int procs) { |
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ForkJoinPool g = (procs == 0) ? new ForkJoinPool() : |
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new ForkJoinPool(procs); |
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System.out.println("Number of procs=" + g.getParallelism()); |
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System.out.println("Integrating from " + start + " to " + end + |
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" forkPolicy = " + forkArg); |
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long lastTime = System.nanoTime(); |
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for (int i = 0; i < 10; ++i) { |
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for (int i = 0; i < 20; ++i) { |
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double a; |
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if (forkPolicy == SERIAL) |
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a = SQuad.computeArea(g, start, end); |
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lastTime = now; |
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System.out.printf("Calls/sec: %12d", (long) (calls / s)); |
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System.out.printf(" Time: %7.3f", s); |
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System.out.printf(" Area: %12.1f", a); |
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System.out.printf(" Threads: %5d", g.getPoolSize()); |
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// System.out.printf(" Area: %12.1f", a); |
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System.out.println(); |
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} |
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System.out.println(g); |
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g.shutdown(); |
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} |
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// Sequential version |
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static final class SQuad extends RecursiveAction { |
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static double computeArea(ForkJoinPool pool, double l, double r) { |
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q.fork(); |
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ar = recEval(c, r, fc, fr, ar); |
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if (!q.tryUnfork()) { |
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q.quietlyHelpJoin(); |
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q.quietlyJoin(); |
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return ar + q.area; |
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} |
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return ar + recEval(l, c, fl, fc, al); |
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(q = new DQuad(l, c, al)).fork(); |
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ar = recEval(c, r, fc, fr, ar); |
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if (q != null && !q.tryUnfork()) { |
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q.quietlyHelpJoin(); |
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q.quietlyJoin(); |
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return ar + q.area; |
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} |
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return ar + recEval(l, c, fl, fc, al); |
