test/loops/FJPhaserJacobi.java

// Barrier version of Jacobi iteration

import java.util.concurrent.*;

public class FJPhaserJacobi {

    static int dimGran;

    static final double EPSILON = 0.0001;  // convergence criterion

    public static void main(String[] args) {
        int n = 2048;
        int steps = 1000;
        try {
            if (args.length > 0)
                n = Integer.parseInt(args[0]);
            if (args.length > 1)
                steps = Integer.parseInt(args[1]);
        }
        
        catch (Exception e) {
            System.out.println("Usage: java ThreadPhaserJacobi <matrix size> <max steps>");
            return;
        }
        
        ForkJoinPool fjp = new ForkJoinPool();
        //        int granularity = (n * n / fjp.getParallelism()) / 2;
        int granularity = n * n / fjp.getParallelism();
        dimGran = (int)(Math.sqrt(granularity));
      
        // 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);
            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);

        }
        
    }

    static class Segment extends CyclicAction {
        double[][] A; // matrix to get old values from
        double[][] B; // matrix to put new values into
        // indices of current submatrix
        final int loRow;   
        final int hiRow;
        final int loCol;
        final int hiCol;
        volatile double maxDiff; // maximum difference between old and new values

        Segment(double[][] A, double[][] B, 
                int loRow, int hiRow,
                int loCol, int hiCol, 
                Phaser br) {
            super(br);
            this.A = A;   this.B = B;
            this.loRow = loRow; this.hiRow = hiRow;
            this.loCol = loCol; this.hiCol = hiCol;
        }

        public void step() {
            maxDiff = update(A, B);
            double[][] tmp = A; A = B; B = tmp;
        }

        double update(double[][] a, double[][] b) {
            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;
                }
            }

            return md;
        }
        
    }

    static class MyPhaser extends Phaser {
        final int max;
        MyPhaser(int steps) { this.max = steps - 1; }
        public boolean onAdvance(int phase, int registeredParties) {
            return phase >= max || registeredParties <= 0;
        }
    }

    static class Driver extends RecursiveAction { 
        double[][] A; // matrix to get old values from
        double[][] B; // matrix to put new values into
        final int loRow;   // indices of current submatrix
        final int hiRow;
        final int loCol;
        final int hiCol;
        final int steps;
        Driver(double[][] mat1, double[][] mat2, 
               int firstRow, int lastRow,
               int firstCol, int lastCol,
               int steps) {
            
            this.A = mat1;   this.B = mat2;
            this.loRow = firstRow; this.hiRow = lastRow;
            this.loCol = firstCol; this.hiCol = lastCol;
            this.steps = steps;
        }

        public void compute() {
            int rows = hiRow - loRow + 1;
            int cols = hiCol - loCol + 1;
            int rblocks = (int)(Math.round((float)rows / dimGran));
            int cblocks = (int)(Math.round((float)cols / dimGran));
            
            int n = rblocks * cblocks;
            
            System.out.println("Using " + n + " segments");
            
            Segment[] segs = new Segment[n];
            Phaser barrier = new MyPhaser(steps);
            int k = 0;
            for (int i = 0; i < rblocks; ++i) {
                int lr = loRow + i * dimGran;
                int hr = lr + dimGran;
                if (i == rblocks-1) hr = hiRow;
                
                for (int j = 0; j < cblocks; ++j) {
                    int lc = loCol + j * dimGran;
                    int hc = lc + dimGran;
                    if (j == cblocks-1) hc = hiCol;
                    
                    segs[k] = new Segment(A, B, lr, hr, lc, hc, barrier);
                    ++k;
                }
            }
            invokeAll(segs);
            double maxd = 0;
            for (k = 0; k < n; ++k) {
                double md = segs[k].maxDiff;
                if (md > maxd) maxd = md;
            }
            System.out.println("Max diff after " + steps + " steps = " + maxd);
        }
    }
}

Revision:	1.7
Committed:	Sun Sep 19 12:55:37 2010 UTC (13 years, 7 months ago) by dl
Branch:	MAIN
Changes since 1.6:	+26 -31 lines
Log Message:	Add and update FJ and Queue tests
#	User	Rev	Content
1	dl	1.1	// Barrier version of Jacobi iteration
2
3			import java.util.concurrent.*;
4
5			public class FJPhaserJacobi {
6
7			static int dimGran;
8
9			static final double EPSILON = 0.0001; // convergence criterion
10
11			public static void main(String[] args) {
12			int n = 2048;
13			int steps = 1000;
14			try {
15			if (args.length > 0)
16			n = Integer.parseInt(args[0]);
17			if (args.length > 1)
18			steps = Integer.parseInt(args[1]);
19			}
20	dl	1.7
21	dl	1.1	catch (Exception e) {
22	dl	1.7	System.out.println("Usage: java ThreadPhaserJacobi <matrix size> <max steps>");
23	dl	1.1	return;
24			}
25	dl	1.7
26	dl	1.1	ForkJoinPool fjp = new ForkJoinPool();
27	dl	1.7	// int granularity = (n * n / fjp.getParallelism()) / 2;
28	dl	1.1	int granularity = n * n / fjp.getParallelism();
29	dl	1.7	dimGran = (int)(Math.sqrt(granularity));
30
31	dl	1.1	// allocate enough space for edges
32			int dim = n+2;
33			int ncells = dim * dim;
34			double[][] a = new double[dim][dim];
35			double[][] b = new double[dim][dim];
36			// Initialize interiors to small value
37	dl	1.7	double smallVal = 1.0/dim;
38	dl	1.1	for (int i = 1; i < dim-1; ++i) {
39			for (int j = 1; j < dim-1; ++j)
40			a[i][j] = smallVal;
41			}
42			int nreps = 3;
43			for (int rep = 0; rep < nreps; ++rep) {
44			// Fill all edges with 1's.
45			for (int k = 0; k < dim; ++k) {
46			a[k][0] += 1.0;
47			a[k][n+1] += 1.0;
48			a[0][k] += 1.0;
49			a[n+1][k] += 1.0;
50			}
51			Driver driver = new Driver(a, b, 1, n, 1, n, steps);
52			long startTime = System.currentTimeMillis();
53			fjp.invoke(driver);
54	dl	1.7
55	dl	1.1	long time = System.currentTimeMillis() - startTime;
56	dl	1.7	double secs = ((double)time) / 1000.0;
57
58	dl	1.1	System.out.println("Compute Time: " + secs);
59			System.out.println(fjp);
60
61			}
62	dl	1.7
63	dl	1.1	}
64
65			static class Segment extends CyclicAction {
66			double[][] A; // matrix to get old values from
67			double[][] B; // matrix to put new values into
68			// indices of current submatrix
69	dl	1.7	final int loRow;
70	dl	1.1	final int hiRow;
71			final int loCol;
72			final int hiCol;
73			volatile double maxDiff; // maximum difference between old and new values
74
75	dl	1.7	Segment(double[][] A, double[][] B,
76	dl	1.1	int loRow, int hiRow,
77	dl	1.7	int loCol, int hiCol,
78	dl	1.1	Phaser br) {
79			super(br);
80			this.A = A; this.B = B;
81			this.loRow = loRow; this.hiRow = hiRow;
82			this.loCol = loCol; this.hiCol = hiCol;
83			}
84
85			public void step() {
86			maxDiff = update(A, B);
87			double[][] tmp = A; A = B; B = tmp;
88			}
89
90			double update(double[][] a, double[][] b) {
91			double md = 0.0; // local for computing max diff
92
93			for (int i = loRow; i <= hiRow; ++i) {
94			for (int j = loCol; j <= hiCol; ++j) {
95			double v = 0.25 * (a[i-1][j] + a[i][j-1] +
96			a[i+1][j] + a[i][j+1]);
97			b[i][j] = v;
98
99			double diff = v - a[i][j];
100			if (diff < 0) diff = -diff;
101			if (diff > md) md = diff;
102			}
103			}
104
105			return md;
106			}
107	dl	1.7
108	dl	1.1	}
109
110			static class MyPhaser extends Phaser {
111			final int max;
112			MyPhaser(int steps) { this.max = steps - 1; }
113			public boolean onAdvance(int phase, int registeredParties) {
114			return phase >= max \|\| registeredParties <= 0;
115			}
116			}
117
118	dl	1.7	static class Driver extends RecursiveAction {
119	dl	1.1	double[][] A; // matrix to get old values from
120			double[][] B; // matrix to put new values into
121			final int loRow; // indices of current submatrix
122			final int hiRow;
123			final int loCol;
124			final int hiCol;
125			final int steps;
126	dl	1.7	Driver(double[][] mat1, double[][] mat2,
127	dl	1.1	int firstRow, int lastRow,
128			int firstCol, int lastCol,
129			int steps) {
130	dl	1.7
131	dl	1.1	this.A = mat1; this.B = mat2;
132			this.loRow = firstRow; this.hiRow = lastRow;
133			this.loCol = firstCol; this.hiCol = lastCol;
134			this.steps = steps;
135			}
136
137			public void compute() {
138			int rows = hiRow - loRow + 1;
139			int cols = hiCol - loCol + 1;
140	dl	1.7	int rblocks = (int)(Math.round((float)rows / dimGran));
141			int cblocks = (int)(Math.round((float)cols / dimGran));
142
143	dl	1.1	int n = rblocks * cblocks;
144	dl	1.7
145	dl	1.1	System.out.println("Using " + n + " segments");
146	dl	1.7
147	dl	1.1	Segment[] segs = new Segment[n];
148			Phaser barrier = new MyPhaser(steps);
149			int k = 0;
150			for (int i = 0; i < rblocks; ++i) {
151			int lr = loRow + i * dimGran;
152			int hr = lr + dimGran;
153			if (i == rblocks-1) hr = hiRow;
154	dl	1.7
155	dl	1.1	for (int j = 0; j < cblocks; ++j) {
156			int lc = loCol + j * dimGran;
157			int hc = lc + dimGran;
158			if (j == cblocks-1) hc = hiCol;
159	dl	1.7
160	dl	1.1	segs[k] = new Segment(A, B, lr, hr, lc, hc, barrier);
161			++k;
162			}
163			}
164			invokeAll(segs);
165			double maxd = 0;
166			for (k = 0; k < n; ++k) {
167			double md = segs[k].maxDiff;
168			if (md > maxd) maxd = md;
169			}
170			System.out.println("Max diff after " + steps + " steps = " + maxd);
171			}
172			}
173			}
174	dl	1.7