我的mpi学习实践

基本学习篇

参考＜并行计算导论＞一书，进行学习：

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安装

mpich下载地址
按照INSTALL的步骤进行安装．

编译链接执行

编译：mpicc -c cpi.c
链接：mpicc -o cpi cpi.o
执行：mpiexec -n 3 cpi //-n代表单机上使用几个节点跑

＼examples\有很多例子，可以跑一些结果试试．

计算积分的例子（第一个mpi程序）

/* 程序来源: MPICH examples/cpi.c */#include "mpi.h"#include <stdio.h>double f( double a ) { return (4.0 / (1.0 + a*a)); }int main( int argc, char *argv[]){int n, myid, numprocs, i, namelen;double PI25DT = 3.141592653589793238462643;double mypi, pi, h, sum, x;double startwtime, endwtime;char processor_name[MPI_MAX_PROCESSOR_NAME];14MPI_Init(&argc,&argv);MPI_Comm_size(MPI_COMM_WORLD,&numprocs);MPI_Comm_rank(MPI_COMM_WORLD,&myid);MPI_Get_processor_name(processor_name,&namelen);fprintf(stderr,"Process %d on %s\n", myid, processor_name);if (myid == 0) {n=10000;startwtime = MPI_Wtime();}MPI_Bcast(&n, 1, MPI_INT, 0, MPI_COMM_WORLD);h = 1.0 / (double) n;sum = 0.0;for (i = myid; i < n; i += numprocs) {x = h * ((double)i + 0.5);sum += f(x);}mypi = h * sum;MPI_Reduce(&mypi, &pi, 1, MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORLD);if (myid == 0) {endwtime = MPI_Wtime();printf("pi is approximately %.16f, error is %.16f\n", pi, pi - PI25DT);printf("wall clock time = %f\n", endwtime-startwtime);}MPI_Finalize();return 0;}