Multiplicación de matriz paralela en Java 6
Ayer hice una pregunta sobre la multiplicación de matrices paralelas en Java 7 usando el framework fork / joinaqu. Con la ayuda de axtavt conseguí que mi programa de ejemplo funcionara. Ahora estoy implementando un programa equivalente usando solo la funcionalidad Java 6. Me sale el mismo problema que ayer, a pesar de aplicar el feedback que axtavt me dio (creo). ¿Estoy pasando por alto algo? Código
package algorithms;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
public class Java6MatrixMultiply implements Algorithm {
private static final int SIZE = 1024;
private static final int THRESHOLD = 64;
private static final int MAX_THREADS = Runtime.getRuntime().availableProcessors();
private final ExecutorService executor = Executors.newFixedThreadPool(MAX_THREADS);
private float[][] a = new float[SIZE][SIZE];
private float[][] b = new float[SIZE][SIZE];
private float[][] c = new float[SIZE][SIZE];
@Override
public void initialize() {
init(a, b, SIZE);
}
@Override
public void execute() {
MatrixMultiplyTask task = new MatrixMultiplyTask(a, 0, 0, b, 0, 0, c, 0, 0, SIZE);
task.split();
executor.shutdown();
try {
executor.awaitTermination(Integer.MAX_VALUE, TimeUnit.DAYS);
} catch (InterruptedException e) {
System.out.println("Error: " + e.getMessage());
}
}
@Override
public void printResult() {
check(c, SIZE);
for (int i = 0; i < SIZE && i <= 10; i++) {
for (int j = 0; j < SIZE && j <= 10; j++) {
if(j == 10) {
System.out.print("...");
}
else {
System.out.print(c[i][j] + " ");
}
}
if(i == 10) {
System.out.println();
for(int k = 0; k < 10; k++) System.out.print(" ... ");
}
System.out.println();
}
System.out.println();
}
// To simplify checking, fill with all 1's. Answer should be all n's.
static void init(float[][] a, float[][] b, int n) {
for (int i = 0; i < n; ++i) {
for (int j = 0; j < n; ++j) {
a[i][j] = 1.0F;
b[i][j] = 1.0F;
}
}
}
static void check(float[][] c, int n) {
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
if (c[i][j] != n) {
throw new Error("Check Failed at [" + i + "][" + j + "]: " + c[i][j]);
//System.out.println("Check Failed at [" + i + "][" + j + "]: " + c[i][j]);
}
}
}
}
public class Seq implements Runnable {
private final MatrixMultiplyTask a;
private final MatrixMultiplyTask b;
public Seq(MatrixMultiplyTask a, MatrixMultiplyTask b, int size) {
this.a = a;
this.b = b;
if (size <= THRESHOLD) {
executor.submit(this);
} else {
a.split();
b.split();
}
}
public void run() {
a.multiplyStride2();
b.multiplyStride2();
}
}
private class MatrixMultiplyTask {
private final float[][] A; // Matrix A
private final int aRow; // first row of current quadrant of A
private final int aCol; // first column of current quadrant of A
private final float[][] B; // Similarly for B
private final int bRow;
private final int bCol;
private final float[][] C; // Similarly for result matrix C
private final int cRow;
private final int cCol;
private final int size;
MatrixMultiplyTask(float[][] A, int aRow, int aCol, float[][] B,
int bRow, int bCol, float[][] C, int cRow, int cCol, int size) {
this.A = A;
this.aRow = aRow;
this.aCol = aCol;
this.B = B;
this.bRow = bRow;
this.bCol = bCol;
this.C = C;
this.cRow = cRow;
this.cCol = cCol;
this.size = size;
}
public void split() {
int h = size / 2;
new Seq(new MatrixMultiplyTask(A,
aRow, aCol, // A11
B, bRow, bCol, // B11
C, cRow, cCol, // C11
h),
new MatrixMultiplyTask(A, aRow, aCol + h, // A12
B, bRow + h, bCol, // B21
C, cRow, cCol, // C11
h), h);
new Seq(new MatrixMultiplyTask(A,
aRow, aCol, // A11
B, bRow, bCol + h, // B12
C, cRow, cCol + h, // C12
h),
new MatrixMultiplyTask(A, aRow, aCol + h, // A12
B, bRow + h, bCol + h, // B22
C, cRow, cCol + h, // C12
h), h);
new Seq(new MatrixMultiplyTask(A, aRow
+ h, aCol, // A21
B, bRow, bCol, // B11
C, cRow + h, cCol, // C21
h),
new MatrixMultiplyTask(A, aRow + h, aCol + h, // A22
B, bRow + h, bCol, // B21
C, cRow + h, cCol, // C21
h), h);
new Seq(new MatrixMultiplyTask(A, aRow
+ h, aCol, // A21
B, bRow, bCol + h, // B12
C, cRow + h, cCol + h, // C22
h),
new MatrixMultiplyTask(A, aRow + h, aCol + h, // A22
B, bRow + h, bCol + h, // B22
C, cRow + h, cCol + h, // C22
h), h);
}
public void multiplyStride2() {
for (int j = 0; j < size; j += 2) {
for (int i = 0; i < size; i += 2) {
float[] a0 = A[aRow + i];
float[] a1 = A[aRow + i + 1];
float s00 = 0.0F;
float s01 = 0.0F;
float s10 = 0.0F;
float s11 = 0.0F;
for (int k = 0; k < size; k += 2) {
float[] b0 = B[bRow + k];
s00 += a0[aCol + k] * b0[bCol + j];
s10 += a1[aCol + k] * b0[bCol + j];
s01 += a0[aCol + k] * b0[bCol + j + 1];
s11 += a1[aCol + k] * b0[bCol + j + 1];
float[] b1 = B[bRow + k + 1];
s00 += a0[aCol + k + 1] * b1[bCol + j];
s10 += a1[aCol + k + 1] * b1[bCol + j];
s01 += a0[aCol + k + 1] * b1[bCol + j + 1];
s11 += a1[aCol + k + 1] * b1[bCol + j + 1];
}
C[cRow + i][cCol + j] += s00;
C[cRow + i][cCol + j + 1] += s01;
C[cRow + i + 1][cCol + j] += s10;
C[cRow + i + 1][cCol + j + 1] += s11;
}
}
}
}
}