并行编程：Java线程、OpenMP与MPI
1. Java线程编程
Java线程编程是实现并行计算的重要手段，下面将介绍几个关键的Java线程编程示例。
1.1 矩阵乘法线程实现
以下是一个简单的矩阵乘法线程实现代码：
run() { for ( int j=0; j<x.length; ++j ) y[id] += A[id][j]*x[j]; } public static void main(String args[]) { double[][] A = new double[N][N]; double[] x = new double[N]; Runnable[] mMS = new matMultRunnable[N]; //one thread per row Thread[] th = new Thread[N]; //initialize the data for ( int i=0; i<N; ++i ) { x[i] = 1; for ( int j=0; j<N; ++j ) a[i][j] = 1; } //instantiate the row calculators for ( int i=0; i<N; +
