test/loops/FJJacobi.java

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/licenses/publicdomain
 */

// Jacobi iteration on a mesh. Based loosely on a Filaments demo

import java.util.concurrent.*;
//import jsr166y.*;

public class FJJacobi {

    static final int DEFAULT_GRANULARITY = 4096; // 1024;

    /**
     * The maximum number of matrix cells
     * at which to stop recursing down and instead directly update.
     **/

    static final double EPSILON = 0.0001;  // convergence criterion

    public static void main(String[] args) throws Exception {
        int n = 2048;
        int steps = 1000;
        int granularity = DEFAULT_GRANULARITY;

        try {
            if (args.length > 0)
                n = Integer.parseInt(args[0]);
            if (args.length > 1)
                steps = Integer.parseInt(args[1]);
            if (args.length > 2)
                granularity = Integer.parseInt(args[2]);
        }

        catch (Exception e) {
            System.out.println("Usage: java FJJacobi <matrix size> <max steps> [<leafcells>]");
            return;
        }

        ForkJoinPool fjp = new ForkJoinPool();

        // allocate enough space for edges
        int dim = n+2;
        int ncells = dim * dim;
        double[][] a = new double[dim][dim];
        double[][] b = new double[dim][dim];
        // Initialize interiors to small value
        double smallVal = 1.0/dim;
        for (int i = 1; i < dim-1; ++i) {
            for (int j = 1; j < dim-1; ++j)
                a[i][j] = smallVal;
        }

        int nreps = 3;
        for (int rep = 0; rep < nreps; ++rep) {
            // Fill all edges with 1's.
            for (int k = 0; k < dim; ++k) {
                a[k][0] += 1.0;
                a[k][n+1] += 1.0;
                a[0][k] += 1.0;
                a[n+1][k] += 1.0;
            }
            Driver driver = new Driver(a, b, 1, n, 1, n, steps, granularity);

            long startTime = System.currentTimeMillis();
            fjp.invoke(driver);

            long time = System.currentTimeMillis() - startTime;
            double secs = ((double)time) / 1000.0;

            System.out.println("Compute Time: " + secs);
            System.out.println("Workers: " + fjp.getPoolSize());
            System.out.println(fjp);
        }
    }


    abstract static class MatrixTree extends RecursiveAction {
        // maximum difference between old and new values
        double maxDiff;
        public final double directCompute() {
            compute();
            return maxDiff;
        }
        public final double joinAndReinitialize(double md) {
            if (tryUnfork())
                compute();
            else {
                //                quietlyJoin();
                quietlyHelpJoin();
                reinitialize();
            }
            double m = maxDiff;
            return (md > m) ? md : m;
        }

    }


    static final class LeafNode extends MatrixTree {
        final double[][] A; // matrix to get old values from
        final double[][] B; // matrix to put new values into

        // indices of current submatrix
        final int loRow;    final int hiRow;
        final int loCol;    final int hiCol;

        int steps = 0; // track even/odd steps

        LeafNode(double[][] A, double[][] B,
                 int loRow, int hiRow,
                 int loCol, int hiCol) {
            this.A = A;   this.B = B;
            this.loRow = loRow; this.hiRow = hiRow;
            this.loCol = loCol; this.hiCol = hiCol;
        }

        public void compute() {
            boolean AtoB = (steps++ & 1) == 0;
            double[][] a = AtoB ? A : B;
            double[][] b = AtoB ? B : A;

            double md = 0.0; // local for computing max diff

            for (int i = loRow; i <= hiRow; ++i) {
                for (int j = loCol; j <= hiCol; ++j) {
                    double v = 0.25 * (a[i-1][j] + a[i][j-1] +
                                       a[i+1][j] + a[i][j+1]);
                    b[i][j] = v;

                    double diff = v - a[i][j];
                    if (diff < 0) diff = -diff;
                    if (diff > md) md = diff;
                }
            }

            maxDiff = md;
        }
    }

    static final class FourNode extends MatrixTree {
        final MatrixTree q1;
        final MatrixTree q2;
        final MatrixTree q3;
        final MatrixTree q4;
        FourNode(MatrixTree q1, MatrixTree q2,
                 MatrixTree q3, MatrixTree q4) {
            this.q1 = q1; this.q2 = q2; this.q3 = q3; this.q4 = q4;
        }

        public void compute() {
            q4.fork();
            q3.fork();
            q2.fork();
            double md = q1.directCompute();
            md = q2.joinAndReinitialize(md);
            md = q3.joinAndReinitialize(md);
            md = q4.joinAndReinitialize(md);
            maxDiff = md;
        }
    }


    static final class TwoNode extends MatrixTree {
        final MatrixTree q1;
        final MatrixTree q2;

        TwoNode(MatrixTree q1, MatrixTree q2) {
            this.q1 = q1; this.q2 = q2;
        }

        public void compute() {
            q2.fork();
            maxDiff = q2.joinAndReinitialize(q1.directCompute());
        }

    }


    static final class Driver extends RecursiveAction {
        MatrixTree mat;
        double[][] A; double[][] B;
        int firstRow; int lastRow;
        int firstCol; int lastCol;
        final int steps;
        final int leafs;
        int nleaf;

        Driver(double[][] A, double[][] B,
               int firstRow, int lastRow,
               int firstCol, int lastCol,
               int steps, int leafs) {
            this.A = A;
            this.B = B;
            this.firstRow = firstRow;
            this.firstCol = firstCol;
            this.lastRow = lastRow;
            this.lastCol = lastCol;
            this.steps = steps;
            this.leafs = leafs;
            mat = build(A, B, firstRow, lastRow, firstCol, lastCol, leafs);
            System.out.println("Using " + nleaf + " segments");

        }

        MatrixTree build(double[][] a, double[][] b,
                         int lr, int hr, int lc, int hc, int leafs) {
            int rows = (hr - lr + 1);
            int cols = (hc - lc + 1);

            int mr = (lr + hr) >>> 1; // midpoints
            int mc = (lc + hc) >>> 1;

            int hrows = (mr - lr + 1);
            int hcols = (mc - lc + 1);

            if (rows * cols <= leafs) {
                ++nleaf;
                return new LeafNode(a, b, lr, hr, lc, hc);
            }
            else if (hrows * hcols >= leafs) {
                return new FourNode(build(a, b, lr,   mr, lc,   mc, leafs),
                                    build(a, b, lr,   mr, mc+1, hc, leafs),
                                    build(a, b, mr+1, hr, lc,   mc, leafs),
                                    build(a, b, mr+1, hr, mc+1, hc, leafs));
            }
            else if (cols >= rows) {
                return new TwoNode(build(a, b, lr, hr, lc,   mc, leafs),
                                   build(a, b, lr, hr, mc+1, hc, leafs));
            }
            else {
                return new TwoNode(build(a, b, lr,   mr, lc, hc, leafs),
                                   build(a, b, mr+1, hr, lc, hc, leafs));

            }
        }

        static void doCompute(MatrixTree m, int s) {
            for (int i = 0; i < s; ++i) {
                m.invoke();
                m.reinitialize();
            }
        }

        public void compute() {
            doCompute(mat, steps);
            double md = mat.maxDiff;
            System.out.println("max diff after " + steps + " steps = " + md);
        }
    }


}
Revision:	1.3
Committed:	Mon Nov 2 23:42:46 2009 UTC (14 years, 6 months ago) by jsr166
Branch:	MAIN
Changes since 1.2:	+3 -3 lines
Log Message:	whitespace
#	User	Rev	Content
1	dl	1.1	/*
2			* Written by Doug Lea with assistance from members of JCP JSR-166
3			* Expert Group and released to the public domain, as explained at
4			* http://creativecommons.org/licenses/publicdomain
5			*/
6
7			// Jacobi iteration on a mesh. Based loosely on a Filaments demo
8
9			import java.util.concurrent.*;
10			//import jsr166y.*;
11
12			public class FJJacobi {
13
14			static final int DEFAULT_GRANULARITY = 4096; // 1024;
15
16	jsr166	1.2	/**
17			* The maximum number of matrix cells
18	dl	1.1	* at which to stop recursing down and instead directly update.
19			**/
20
21			static final double EPSILON = 0.0001; // convergence criterion
22
23			public static void main(String[] args) throws Exception {
24			int n = 2048;
25			int steps = 1000;
26			int granularity = DEFAULT_GRANULARITY;
27	jsr166	1.2
28	dl	1.1	try {
29			if (args.length > 0)
30			n = Integer.parseInt(args[0]);
31			if (args.length > 1)
32			steps = Integer.parseInt(args[1]);
33	jsr166	1.2	if (args.length > 2)
34	dl	1.1	granularity = Integer.parseInt(args[2]);
35			}
36	jsr166	1.2
37	dl	1.1	catch (Exception e) {
38			System.out.println("Usage: java FJJacobi <matrix size> <max steps> [<leafcells>]");
39			return;
40			}
41
42			ForkJoinPool fjp = new ForkJoinPool();
43
44			// allocate enough space for edges
45			int dim = n+2;
46			int ncells = dim * dim;
47			double[][] a = new double[dim][dim];
48			double[][] b = new double[dim][dim];
49			// Initialize interiors to small value
50	jsr166	1.2	double smallVal = 1.0/dim;
51	dl	1.1	for (int i = 1; i < dim-1; ++i) {
52			for (int j = 1; j < dim-1; ++j)
53			a[i][j] = smallVal;
54			}
55	jsr166	1.2
56	dl	1.1	int nreps = 3;
57			for (int rep = 0; rep < nreps; ++rep) {
58			// Fill all edges with 1's.
59			for (int k = 0; k < dim; ++k) {
60			a[k][0] += 1.0;
61			a[k][n+1] += 1.0;
62			a[0][k] += 1.0;
63			a[n+1][k] += 1.0;
64			}
65			Driver driver = new Driver(a, b, 1, n, 1, n, steps, granularity);
66	jsr166	1.2
67	dl	1.1	long startTime = System.currentTimeMillis();
68			fjp.invoke(driver);
69	jsr166	1.2
70	dl	1.1	long time = System.currentTimeMillis() - startTime;
71			double secs = ((double)time) / 1000.0;
72	jsr166	1.2
73	dl	1.1	System.out.println("Compute Time: " + secs);
74			System.out.println("Workers: " + fjp.getPoolSize());
75			System.out.println(fjp);
76			}
77			}
78
79
80			abstract static class MatrixTree extends RecursiveAction {
81			// maximum difference between old and new values
82	jsr166	1.2	double maxDiff;
83			public final double directCompute() {
84			compute();
85	dl	1.1	return maxDiff;
86			}
87			public final double joinAndReinitialize(double md) {
88			if (tryUnfork())
89	jsr166	1.2	compute();
90	dl	1.1	else {
91			// quietlyJoin();
92			quietlyHelpJoin();
93			reinitialize();
94			}
95			double m = maxDiff;
96	jsr166	1.3	return (md > m) ? md : m;
97	dl	1.1	}
98
99			}
100
101
102			static final class LeafNode extends MatrixTree {
103			final double[][] A; // matrix to get old values from
104			final double[][] B; // matrix to put new values into
105
106			// indices of current submatrix
107			final int loRow; final int hiRow;
108			final int loCol; final int hiCol;
109
110			int steps = 0; // track even/odd steps
111
112	jsr166	1.2	LeafNode(double[][] A, double[][] B,
113	dl	1.1	int loRow, int hiRow,
114			int loCol, int hiCol) {
115			this.A = A; this.B = B;
116			this.loRow = loRow; this.hiRow = hiRow;
117			this.loCol = loCol; this.hiCol = hiCol;
118			}
119
120	jsr166	1.2	public void compute() {
121	dl	1.1	boolean AtoB = (steps++ & 1) == 0;
122	jsr166	1.3	double[][] a = AtoB ? A : B;
123			double[][] b = AtoB ? B : A;
124	dl	1.1
125			double md = 0.0; // local for computing max diff
126
127			for (int i = loRow; i <= hiRow; ++i) {
128			for (int j = loCol; j <= hiCol; ++j) {
129			double v = 0.25 * (a[i-1][j] + a[i][j-1] +
130			a[i+1][j] + a[i][j+1]);
131			b[i][j] = v;
132
133			double diff = v - a[i][j];
134			if (diff < 0) diff = -diff;
135			if (diff > md) md = diff;
136			}
137			}
138
139			maxDiff = md;
140			}
141			}
142
143			static final class FourNode extends MatrixTree {
144			final MatrixTree q1;
145			final MatrixTree q2;
146			final MatrixTree q3;
147			final MatrixTree q4;
148	jsr166	1.2	FourNode(MatrixTree q1, MatrixTree q2,
149	dl	1.1	MatrixTree q3, MatrixTree q4) {
150			this.q1 = q1; this.q2 = q2; this.q3 = q3; this.q4 = q4;
151			}
152
153	jsr166	1.2	public void compute() {
154	dl	1.1	q4.fork();
155			q3.fork();
156			q2.fork();
157			double md = q1.directCompute();
158			md = q2.joinAndReinitialize(md);
159			md = q3.joinAndReinitialize(md);
160			md = q4.joinAndReinitialize(md);
161			maxDiff = md;
162			}
163			}
164	jsr166	1.2
165	dl	1.1
166			static final class TwoNode extends MatrixTree {
167			final MatrixTree q1;
168			final MatrixTree q2;
169
170			TwoNode(MatrixTree q1, MatrixTree q2) {
171			this.q1 = q1; this.q2 = q2;
172			}
173
174	jsr166	1.2	public void compute() {
175	dl	1.1	q2.fork();
176			maxDiff = q2.joinAndReinitialize(q1.directCompute());
177			}
178	jsr166	1.2
179	dl	1.1	}
180	jsr166	1.2
181	dl	1.1
182			static final class Driver extends RecursiveAction {
183			MatrixTree mat;
184			double[][] A; double[][] B;
185			int firstRow; int lastRow;
186			int firstCol; int lastCol;
187			final int steps;
188			final int leafs;
189			int nleaf;
190
191	jsr166	1.2	Driver(double[][] A, double[][] B,
192	dl	1.1	int firstRow, int lastRow,
193			int firstCol, int lastCol,
194			int steps, int leafs) {
195			this.A = A;
196			this.B = B;
197			this.firstRow = firstRow;
198			this.firstCol = firstCol;
199			this.lastRow = lastRow;
200			this.lastCol = lastCol;
201			this.steps = steps;
202			this.leafs = leafs;
203			mat = build(A, B, firstRow, lastRow, firstCol, lastCol, leafs);
204			System.out.println("Using " + nleaf + " segments");
205
206			}
207
208			MatrixTree build(double[][] a, double[][] b,
209			int lr, int hr, int lc, int hc, int leafs) {
210			int rows = (hr - lr + 1);
211			int cols = (hc - lc + 1);
212
213			int mr = (lr + hr) >>> 1; // midpoints
214			int mc = (lc + hc) >>> 1;
215	jsr166	1.2
216	dl	1.1	int hrows = (mr - lr + 1);
217			int hcols = (mc - lc + 1);
218
219			if (rows * cols <= leafs) {
220			++nleaf;
221			return new LeafNode(a, b, lr, hr, lc, hc);
222			}
223			else if (hrows * hcols >= leafs) {
224			return new FourNode(build(a, b, lr, mr, lc, mc, leafs),
225			build(a, b, lr, mr, mc+1, hc, leafs),
226			build(a, b, mr+1, hr, lc, mc, leafs),
227			build(a, b, mr+1, hr, mc+1, hc, leafs));
228			}
229			else if (cols >= rows) {
230			return new TwoNode(build(a, b, lr, hr, lc, mc, leafs),
231			build(a, b, lr, hr, mc+1, hc, leafs));
232			}
233			else {
234			return new TwoNode(build(a, b, lr, mr, lc, hc, leafs),
235			build(a, b, mr+1, hr, lc, hc, leafs));
236	jsr166	1.2
237	dl	1.1	}
238			}
239
240			static void doCompute(MatrixTree m, int s) {
241			for (int i = 0; i < s; ++i) {
242			m.invoke();
243			m.reinitialize();
244			}
245			}
246
247			public void compute() {
248			doCompute(mat, steps);
249			double md = mat.maxDiff;
250			System.out.println("max diff after " + steps + " steps = " + md);
251			}
252			}
253
254
255			}