MPI 学习

一、编译MPI

mpic++ test.cc -o test

二、启动MPI

mpiexec -np 10 ./test

三、几个例子

第一个进程向第二个发一个数，第二个进程向第三个进程发送一个数。。。依次传递

 #include "mpi.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
 #include <string.h>
 #include <iostream>
 #include <unistd.h>

 using namespace std;

 int main(int argc, char **argv)
 {
     int myid, numprocs, num;

     MPI_Init(&argc, &argv);
     MPI_Comm_rank(MPI_COMM_WORLD, &myid);
     MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
     MPI_Status status;

     if (numprocs < ) {
         printf("Processes must >= 2! \n");
         MPI_Abort(MPI_COMM_WORLD, );
     }

     do {
         //master
         if (myid == ) {
             cout << "please input a number" << endl;
             cin >> num;
             //send number
             if (numprocs > ) {
                 MPI_Send(&num, , MPI_INT, myid + , , MPI_COMM_WORLD);
                 cout << myid << " send " << num << " to " << myid +  << endl;
             }
         }
         //slave
         else {
             MPI_Recv(&num, , MPI_INT, myid - , , MPI_COMM_WORLD, &status);
             cout << myid << " receive " << num << " from " << myid -  << endl;
             if (myid < numprocs - ) {
                 MPI_Send(&num, , MPI_INT, myid + , , MPI_COMM_WORLD);
                 cout << myid << " send " << num << " to " << myid +  << endl;
             }
         }
         MPI_Barrier(MPI_COMM_WORLD); // wait all pro finish
     } while (num > );

     MPI_Finalize();

     return ;
 }

收集(Gather)   http://scc.ustc.edu.cn/zlsc/cxyy/200910/MPICH/mpi45.htm

http://scc.ustc.edu.cn/zlsc/cxyy/200910/MPICH