test/loops/CCJacobi.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/publicdomain/zero/1.0/
 */

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

import java.util.concurrent.*;

public class CCJacobi {

    //    static final int DEFAULT_GRANULARITY = 4096;
    static final int DEFAULT_GRANULARITY = 256;

    /**
     * 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 = EPSILON; // 1.0/dim;
        for (int i = 1; i < dim-1; ++i) {
            for (int j = 1; j < dim-1; ++j)
                a[i][j] = smallVal;
        }
        // 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;
            b[k][0] = 1.0;
            b[k][n+1] = 1.0;
            b[0][k] = 1.0;
            b[n+1][k] = 1.0;
        }
        int nreps = 10;
        for (int rep = 0; rep < nreps; ++rep) {
            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(fjp);
        }
    }

    abstract static class MatrixTree extends CountedCompleter<Void> {
        // maximum difference between old and new values
        double maxDiff;
        MatrixTree(CountedCompleter<?> p, int c) { super(p, c); }
    }

    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(CountedCompleter<?> p,
                 double[][] A, double[][] B,
                 int loRow, int hiRow,
                 int loCol, int hiCol) {
            super(p, 0);
            this.A = A;   this.B = B;
            this.loRow = loRow; this.hiRow = hiRow;
            this.loCol = loCol; this.hiCol = hiCol;
        }

        public final 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;
            tryComplete();
        }
    }

    static final class FourNode extends MatrixTree {
        MatrixTree q1;
        MatrixTree q2;
        MatrixTree q3;
        MatrixTree q4;
        FourNode(CountedCompleter<?> p) {
            super(p, 3);
        }

        public void onCompletion(CountedCompleter<?> caller) {
            double md = q1.maxDiff, m;
            if ((m = q2.maxDiff) > md)
                md = m;
            if ((m = q3.maxDiff) > md)
                md = m;
            if ((m = q4.maxDiff) > md)
                md = m;
            maxDiff = md;
            setPendingCount(3);
        }

        public final void compute() {
            q4.fork();
            q3.fork();
            q2.fork();
            q1.compute();
        }
    }

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

        TwoNode(CountedCompleter<?> p) {
            super(p, 1);
        }

        public void onCompletion(CountedCompleter<?> caller) {
            double md = q1.maxDiff, m;
            if ((m = q2.maxDiff) > md)
                md = m;
            maxDiff = md;
            setPendingCount(1);
        }

        public final void compute() {
            q2.fork();
            q1.compute();
        }

    }

    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(null, A, B, firstRow, lastRow, firstCol, lastCol, leafs);
            System.out.println("Using " + nleaf + " segments");

        }

        MatrixTree build(MatrixTree p,
                         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(p, a, b, lr, hr, lc, hc);
            }
            else if (hrows * hcols >= leafs) {
                FourNode q = new FourNode(p);
                q.q1 = build(q, a, b, lr,   mr, lc,   mc, leafs);
                q.q2 = build(q, a, b, lr,   mr, mc+1, hc, leafs);
                q.q3 = build(q, a, b, mr+1, hr, lc,   mc, leafs);
                q.q4 = build(q, a, b, mr+1, hr, mc+1, hc, leafs);
                return q;
            }
            else if (cols >= rows) {
                TwoNode q = new TwoNode(p);
                q.q1 = build(q, a, b, lr, hr, lc,   mc, leafs);
                q.q2 = build(q, a, b, lr, hr, mc+1, hc, leafs);
                return q;
            }
            else {
                TwoNode q = new TwoNode(p);
                q.q1 = build(q, a, b, lr,   mr, lc, hc, leafs);
                q.q2 = build(q, a, b, mr+1, hr, lc, hc, leafs);
                return q;
            }
        }

        static void doCompute(MatrixTree m, int s) {
            for (int i = 0; i < s; ++i) {
                m.setPendingCount(3);
                m.invoke();
                m.reinitialize();
            }
        }

        public void compute() {
            doCompute(mat, steps);
            double md = mat.maxDiff;
            System.out.println("max diff after " + steps + " steps = " + md);
        }
    }
}
Revision:	1.4
Committed:	Thu Jan 15 18:34:18 2015 UTC (9 years, 3 months ago) by jsr166
Branch:	MAIN
Changes since 1.3:	+0 -5 lines
Log Message:	delete extraneous blank lines
#	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/publicdomain/zero/1.0/
5			*/
6
7			// Jacobi iteration on a mesh. Based loosely on a Filaments demo
8
9			import java.util.concurrent.*;
10
11			public class CCJacobi {
12
13			// static final int DEFAULT_GRANULARITY = 4096;
14			static final int DEFAULT_GRANULARITY = 256;
15
16			/**
17			* The maximum number of matrix cells
18			* at which to stop recursing down and instead directly update.
19			*/
20			static final double EPSILON = 0.0001; // convergence criterion
21
22			public static void main(String[] args) throws Exception {
23			int n = 2048;
24			int steps = 1000;
25			int granularity = DEFAULT_GRANULARITY;
26
27			try {
28			if (args.length > 0)
29			n = Integer.parseInt(args[0]);
30			if (args.length > 1)
31			steps = Integer.parseInt(args[1]);
32			if (args.length > 2)
33			granularity = Integer.parseInt(args[2]);
34			}
35
36			catch (Exception e) {
37			System.out.println("Usage: java FJJacobi <matrix size> <max steps> [<leafcells>]");
38			return;
39			}
40
41			ForkJoinPool fjp = new ForkJoinPool();
42
43			// allocate enough space for edges
44			int dim = n+2;
45			int ncells = dim * dim;
46			double[][] a = new double[dim][dim];
47			double[][] b = new double[dim][dim];
48			// Initialize interiors to small value
49			double smallVal = EPSILON; // 1.0/dim;
50			for (int i = 1; i < dim-1; ++i) {
51			for (int j = 1; j < dim-1; ++j)
52			a[i][j] = smallVal;
53			}
54			// Fill all edges with 1's.
55			for (int k = 0; k < dim; ++k) {
56			a[k][0] = 1.0;
57			a[k][n+1] = 1.0;
58			a[0][k] = 1.0;
59			a[n+1][k] = 1.0;
60			b[k][0] = 1.0;
61			b[k][n+1] = 1.0;
62			b[0][k] = 1.0;
63			b[n+1][k] = 1.0;
64			}
65			int nreps = 10;
66			for (int rep = 0; rep < nreps; ++rep) {
67			Driver driver = new Driver(a, b, 1, n, 1, n, steps, granularity);
68
69			long startTime = System.currentTimeMillis();
70			fjp.invoke(driver);
71
72			long time = System.currentTimeMillis() - startTime;
73			double secs = ((double)time) / 1000.0;
74
75			System.out.println("Compute Time: " + secs);
76			System.out.println(fjp);
77			}
78			}
79
80	dl	1.3	abstract static class MatrixTree extends CountedCompleter<Void> {
81	dl	1.1	// maximum difference between old and new values
82			double maxDiff;
83	dl	1.3	MatrixTree(CountedCompleter<?> p, int c) { super(p, c); }
84	dl	1.1	}
85
86			static final class LeafNode extends MatrixTree {
87			final double[][] A; // matrix to get old values from
88			final double[][] B; // matrix to put new values into
89
90			// indices of current submatrix
91			final int loRow; final int hiRow;
92			final int loCol; final int hiCol;
93
94			int steps = 0; // track even/odd steps
95
96	dl	1.3	LeafNode(CountedCompleter<?> p,
97	dl	1.1	double[][] A, double[][] B,
98			int loRow, int hiRow,
99			int loCol, int hiCol) {
100			super(p, 0);
101			this.A = A; this.B = B;
102			this.loRow = loRow; this.hiRow = hiRow;
103			this.loCol = loCol; this.hiCol = hiCol;
104			}
105
106			public final void compute() {
107			boolean AtoB = (steps++ & 1) == 0;
108			double[][] a = AtoB ? A : B;
109			double[][] b = AtoB ? B : A;
110
111			double md = 0.0; // local for computing max diff
112
113			for (int i = loRow; i <= hiRow; ++i) {
114			for (int j = loCol; j <= hiCol; ++j) {
115			double v = 0.25 * (a[i-1][j] + a[i][j-1] +
116			a[i+1][j] + a[i][j+1]);
117			b[i][j] = v;
118
119			double diff = v - a[i][j];
120			if (diff < 0) diff = -diff;
121			if (diff > md) md = diff;
122			}
123			}
124
125			maxDiff = md;
126	jsr166	1.2	tryComplete();
127	dl	1.1	}
128			}
129
130			static final class FourNode extends MatrixTree {
131			MatrixTree q1;
132			MatrixTree q2;
133			MatrixTree q3;
134			MatrixTree q4;
135	dl	1.3	FourNode(CountedCompleter<?> p) {
136	dl	1.1	super(p, 3);
137			}
138
139	dl	1.3	public void onCompletion(CountedCompleter<?> caller) {
140	dl	1.1	double md = q1.maxDiff, m;
141			if ((m = q2.maxDiff) > md)
142			md = m;
143			if ((m = q3.maxDiff) > md)
144			md = m;
145			if ((m = q4.maxDiff) > md)
146			md = m;
147			maxDiff = md;
148			setPendingCount(3);
149			}
150
151			public final void compute() {
152			q4.fork();
153			q3.fork();
154			q2.fork();
155			q1.compute();
156			}
157			}
158
159			static final class TwoNode extends MatrixTree {
160			MatrixTree q1;
161			MatrixTree q2;
162
163	dl	1.3	TwoNode(CountedCompleter<?> p) {
164	dl	1.1	super(p, 1);
165			}
166
167	dl	1.3	public void onCompletion(CountedCompleter<?> caller) {
168	dl	1.1	double md = q1.maxDiff, m;
169			if ((m = q2.maxDiff) > md)
170			md = m;
171			maxDiff = md;
172			setPendingCount(1);
173			}
174
175			public final void compute() {
176			q2.fork();
177			q1.compute();
178			}
179
180			}
181
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			Driver(double[][] A, double[][] B,
192			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(null, A, B, firstRow, lastRow, firstCol, lastCol, leafs);
204			System.out.println("Using " + nleaf + " segments");
205
206			}
207
208			MatrixTree build(MatrixTree p,
209			double[][] a, double[][] b,
210			int lr, int hr, int lc, int hc, int leafs) {
211			int rows = (hr - lr + 1);
212			int cols = (hc - lc + 1);
213
214			int mr = (lr + hr) >>> 1; // midpoints
215			int mc = (lc + hc) >>> 1;
216
217			int hrows = (mr - lr + 1);
218			int hcols = (mc - lc + 1);
219
220			if (rows * cols <= leafs) {
221			++nleaf;
222			return new LeafNode(p, a, b, lr, hr, lc, hc);
223			}
224			else if (hrows * hcols >= leafs) {
225			FourNode q = new FourNode(p);
226			q.q1 = build(q, a, b, lr, mr, lc, mc, leafs);
227			q.q2 = build(q, a, b, lr, mr, mc+1, hc, leafs);
228			q.q3 = build(q, a, b, mr+1, hr, lc, mc, leafs);
229			q.q4 = build(q, a, b, mr+1, hr, mc+1, hc, leafs);
230			return q;
231			}
232			else if (cols >= rows) {
233			TwoNode q = new TwoNode(p);
234			q.q1 = build(q, a, b, lr, hr, lc, mc, leafs);
235			q.q2 = build(q, a, b, lr, hr, mc+1, hc, leafs);
236			return q;
237			}
238			else {
239			TwoNode q = new TwoNode(p);
240			q.q1 = build(q, a, b, lr, mr, lc, hc, leafs);
241			q.q2 = build(q, a, b, mr+1, hr, lc, hc, leafs);
242			return q;
243			}
244			}
245
246			static void doCompute(MatrixTree m, int s) {
247			for (int i = 0; i < s; ++i) {
248			m.setPendingCount(3);
249			m.invoke();
250			m.reinitialize();
251			}
252			}
253
254			public void compute() {
255			doCompute(mat, steps);
256			double md = mat.maxDiff;
257			System.out.println("max diff after " + steps + " steps = " + md);
258			}
259			}
260			}