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/publicdomain/zero/1.0/
 */

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

import java.util.concurrent.*;

public class FJJacobi {

    //    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 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();
                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:	1.12
Committed:	Thu Jan 15 18:34:19 2015 UTC (9 years, 4 months ago) by jsr166
Branch:	MAIN
Changes since 1.11:	+0 -6 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	jsr166	1.10	* http://creativecommons.org/publicdomain/zero/1.0/
5	dl	1.1	*/
6
7			// Jacobi iteration on a mesh. Based loosely on a Filaments demo
8
9			import java.util.concurrent.*;
10
11			public class FJJacobi {
12
13	dl	1.11	// static final int DEFAULT_GRANULARITY = 4096;
14			static final int DEFAULT_GRANULARITY = 256;
15	dl	1.1
16	jsr166	1.7	/**
17			* The maximum number of matrix cells
18	dl	1.1	* at which to stop recursing down and instead directly update.
19	jsr166	1.8	*/
20	dl	1.1	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	jsr166	1.7
27	dl	1.1	try {
28			if (args.length > 0)
29			n = Integer.parseInt(args[0]);
30			if (args.length > 1)
31			steps = Integer.parseInt(args[1]);
32	jsr166	1.7	if (args.length > 2)
33	dl	1.1	granularity = Integer.parseInt(args[2]);
34			}
35	jsr166	1.7
36	dl	1.1	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	jsr166	1.7	double smallVal = EPSILON; // 1.0/dim;
50	dl	1.1	for (int i = 1; i < dim-1; ++i) {
51			for (int j = 1; j < dim-1; ++j)
52			a[i][j] = smallVal;
53			}
54	dl	1.6	// 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	dl	1.1	for (int rep = 0; rep < nreps; ++rep) {
67			Driver driver = new Driver(a, b, 1, n, 1, n, steps, granularity);
68	jsr166	1.7
69	dl	1.1	long startTime = System.currentTimeMillis();
70			fjp.invoke(driver);
71	jsr166	1.7
72	dl	1.1	long time = System.currentTimeMillis() - startTime;
73	dl	1.6	double secs = ((double)time) / 1000.0;
74	jsr166	1.7
75	dl	1.1	System.out.println("Compute Time: " + secs);
76			System.out.println(fjp);
77			}
78			}
79
80			abstract static class MatrixTree extends RecursiveAction {
81			// maximum difference between old and new values
82	jsr166	1.7	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	1.7	compute();
90	dl	1.1	else {
91	dl	1.5	quietlyJoin();
92	dl	1.1	reinitialize();
93			}
94			double m = maxDiff;
95	jsr166	1.9	return (md > m) ? md : m;
96	dl	1.1	}
97
98			}
99
100			static final class LeafNode extends MatrixTree {
101			final double[][] A; // matrix to get old values from
102			final double[][] B; // matrix to put new values into
103
104			// indices of current submatrix
105			final int loRow; final int hiRow;
106			final int loCol; final int hiCol;
107
108			int steps = 0; // track even/odd steps
109
110	jsr166	1.7	LeafNode(double[][] A, double[][] B,
111	dl	1.1	int loRow, int hiRow,
112			int loCol, int hiCol) {
113			this.A = A; this.B = B;
114			this.loRow = loRow; this.hiRow = hiRow;
115			this.loCol = loCol; this.hiCol = hiCol;
116			}
117
118	jsr166	1.7	public void compute() {
119	dl	1.1	boolean AtoB = (steps++ & 1) == 0;
120	jsr166	1.9	double[][] a = AtoB ? A : B;
121			double[][] b = AtoB ? B : A;
122	dl	1.1
123			double md = 0.0; // local for computing max diff
124
125			for (int i = loRow; i <= hiRow; ++i) {
126			for (int j = loCol; j <= hiCol; ++j) {
127			double v = 0.25 * (a[i-1][j] + a[i][j-1] +
128			a[i+1][j] + a[i][j+1]);
129			b[i][j] = v;
130	jsr166	1.7
131	dl	1.1	double diff = v - a[i][j];
132			if (diff < 0) diff = -diff;
133			if (diff > md) md = diff;
134			}
135			}
136
137			maxDiff = md;
138			}
139			}
140
141			static final class FourNode extends MatrixTree {
142			final MatrixTree q1;
143			final MatrixTree q2;
144			final MatrixTree q3;
145			final MatrixTree q4;
146	jsr166	1.7	FourNode(MatrixTree q1, MatrixTree q2,
147	dl	1.1	MatrixTree q3, MatrixTree q4) {
148			this.q1 = q1; this.q2 = q2; this.q3 = q3; this.q4 = q4;
149			}
150
151	jsr166	1.7	public void compute() {
152	dl	1.1	q4.fork();
153			q3.fork();
154			q2.fork();
155			double md = q1.directCompute();
156			md = q2.joinAndReinitialize(md);
157			md = q3.joinAndReinitialize(md);
158			md = q4.joinAndReinitialize(md);
159			maxDiff = md;
160			}
161			}
162	jsr166	1.7
163	dl	1.1	static final class TwoNode extends MatrixTree {
164			final MatrixTree q1;
165			final MatrixTree q2;
166
167			TwoNode(MatrixTree q1, MatrixTree q2) {
168			this.q1 = q1; this.q2 = q2;
169			}
170
171	jsr166	1.7	public void compute() {
172	dl	1.1	q2.fork();
173			maxDiff = q2.joinAndReinitialize(q1.directCompute());
174			}
175	jsr166	1.7
176	dl	1.1	}
177	jsr166	1.7
178	dl	1.1	static final class Driver extends RecursiveAction {
179			MatrixTree mat;
180			double[][] A; double[][] B;
181			int firstRow; int lastRow;
182			int firstCol; int lastCol;
183			final int steps;
184			final int leafs;
185			int nleaf;
186
187	jsr166	1.7	Driver(double[][] A, double[][] B,
188	dl	1.1	int firstRow, int lastRow,
189			int firstCol, int lastCol,
190			int steps, int leafs) {
191			this.A = A;
192			this.B = B;
193			this.firstRow = firstRow;
194			this.firstCol = firstCol;
195			this.lastRow = lastRow;
196			this.lastCol = lastCol;
197			this.steps = steps;
198			this.leafs = leafs;
199			mat = build(A, B, firstRow, lastRow, firstCol, lastCol, leafs);
200			System.out.println("Using " + nleaf + " segments");
201
202			}
203
204			MatrixTree build(double[][] a, double[][] b,
205			int lr, int hr, int lc, int hc, int leafs) {
206			int rows = (hr - lr + 1);
207			int cols = (hc - lc + 1);
208
209			int mr = (lr + hr) >>> 1; // midpoints
210			int mc = (lc + hc) >>> 1;
211	jsr166	1.7
212	dl	1.1	int hrows = (mr - lr + 1);
213			int hcols = (mc - lc + 1);
214
215			if (rows * cols <= leafs) {
216			++nleaf;
217			return new LeafNode(a, b, lr, hr, lc, hc);
218			}
219			else if (hrows * hcols >= leafs) {
220			return new FourNode(build(a, b, lr, mr, lc, mc, leafs),
221			build(a, b, lr, mr, mc+1, hc, leafs),
222			build(a, b, mr+1, hr, lc, mc, leafs),
223			build(a, b, mr+1, hr, mc+1, hc, leafs));
224			}
225			else if (cols >= rows) {
226			return new TwoNode(build(a, b, lr, hr, lc, mc, leafs),
227			build(a, b, lr, hr, mc+1, hc, leafs));
228			}
229			else {
230			return new TwoNode(build(a, b, lr, mr, lc, hc, leafs),
231			build(a, b, mr+1, hr, lc, hc, leafs));
232	jsr166	1.7
233	dl	1.1	}
234			}
235
236			static void doCompute(MatrixTree m, int s) {
237			for (int i = 0; i < s; ++i) {
238			m.invoke();
239			m.reinitialize();
240			}
241			}
242
243			public void compute() {
244			doCompute(mat, steps);
245			double md = mat.maxDiff;
246			System.out.println("max diff after " + steps + " steps = " + md);
247			}
248			}
249			}