7、并行编程：Java线程、OpenMP与MPI

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;
          +