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import java.util.concurrent.*; |
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/** |
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* Sample program using Guassian Quadrature for numerical integration. |
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* Sample program using Gaussian 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 final double start = 0.0; |
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static final double end = 1536.0; |
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/* |
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* The number of recursive calls for |
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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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*/ |
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} |
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} |
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catch (Exception e) { |
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System.out.println("Usage: java Integrate3 threads <s[erial] | d[ynamic] | f[ork] - default d>"); |
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System.out.println("Usage: java Integrate threads <s[erial] | d[ynamic] | f[ork] - default d>"); |
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return; |
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} |
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ForkJoinPool g = new ForkJoinPool(procs); |
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System.out.println("Integrating from " + start + " to " + end + |
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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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double a; |
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if (forkPolicy == SERIAL) |
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a = SQuad.computeArea(g, start, end); |
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else if (forkPolicy == FORK) |
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else if (forkPolicy == FORK) |
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a = FQuad.computeArea(g, start, end); |
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else |
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a = DQuad.computeArea(g, start, end); |
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final double left; // lower bound |
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final double right; // upper bound |
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double area; |
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SQuad(double l, double r, double a) { |
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this.left = l; this.right = r; this.area = a; |
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} |
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public final void compute() { |
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double l = left; |
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double r = right; |
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area = recEval(l, r, (l * l + 1.0) * l, (r * r + 1.0) * r, area); |
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} |
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static final double recEval(double l, double r, double fl, |
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double fr, double a) { |
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double h = (r - l) * 0.5; |
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double c = l + h; |
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double fc = (c * c + 1.0) * c; |
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double fc = (c * c + 1.0) * c; |
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double hh = h * 0.5; |
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double al = (fl + fc) * hh; |
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double al = (fl + fc) * hh; |
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double ar = (fr + fc) * hh; |
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double alr = al + ar; |
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if (Math.abs(alr - a) <= errorTolerance) |
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final double left; // lower bound |
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final double right; // upper bound |
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double area; |
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FQuad(double l, double r, double a) { |
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this.left = l; this.right = r; this.area = a; |
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} |
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public final void compute() { |
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double l = left; |
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double r = right; |
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area = recEval(l, r, (l * l + 1.0) * l, (r * r + 1.0) * r, area); |
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} |
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static final double recEval(double l, double r, double fl, |
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double fr, double a) { |
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double h = (r - l) * 0.5; |
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double c = l + h; |
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double fc = (c * c + 1.0) * c; |
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double fc = (c * c + 1.0) * c; |
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double hh = h * 0.5; |
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double al = (fl + fc) * hh; |
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double al = (fl + fc) * hh; |
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double ar = (fr + fc) * hh; |
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double alr = al + ar; |
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if (Math.abs(alr - a) <= errorTolerance) |
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// ........................... |
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// Version using on-demand Fork |
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// Version using on-demand Fork |
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static final class DQuad extends RecursiveAction { |
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static double computeArea(ForkJoinPool pool, double l, double r) { |
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DQuad q = new DQuad(l, r, 0); |
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final double left; // lower bound |
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final double right; // upper bound |
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double area; |
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DQuad(double l, double r, double a) { |
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this.left = l; this.right = r; this.area = a; |
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} |
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public final void compute() { |
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double l = left; |
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double r = right; |
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area = recEval(l, r, (l * l + 1.0) * l, (r * r + 1.0) * r, area); |
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} |
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static final double recEval(double l, double r, double fl, |
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double fr, double a) { |
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double h = (r - l) * 0.5; |
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double c = l + h; |
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double fc = (c * c + 1.0) * c; |
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double fc = (c * c + 1.0) * c; |
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double hh = h * 0.5; |
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double al = (fl + fc) * hh; |
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double al = (fl + fc) * hh; |
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double ar = (fr + fc) * hh; |
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double alr = al + ar; |
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if (Math.abs(alr - a) <= errorTolerance) |
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} |
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} |
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– |
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