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

 1 #include "mpi.h"
 2 #include <stdio.h>
 3 #include <stdlib.h>
 4 #include <time.h>
 5 #include <string.h>
 6 #include <iostream>
 7 #include <unistd.h>
 8 
 9 
10 using namespace std;
11 
12 int main(int argc, char **argv)
13 {
14     int myid, numprocs, num;
15 
16     MPI_Init(&argc, &argv);
17     MPI_Comm_rank(MPI_COMM_WORLD, &myid);
18     MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
19     MPI_Status status;
20 
21     if (numprocs < 2) {
22         printf("Processes must >= 2! 
");
23         MPI_Abort(MPI_COMM_WORLD, 99);
24     }
25 
26     do {
27         //master
28         if (myid == 0) {
29             cout << "please input a number" << endl;
30             cin >> num;
31             //send number
32             if (numprocs > 1) {
33                 MPI_Send(&num, 1, MPI_INT, myid + 1, 0, MPI_COMM_WORLD);
34                 cout << myid << " send " << num << " to " << myid + 1 << endl;
35             }
36         }
37         //slave
38         else {
39             MPI_Recv(&num, 1, MPI_INT, myid - 1, 0, MPI_COMM_WORLD, &status);
40             cout << myid << " receive " << num << " from " << myid - 1 << endl;
41             if (myid < numprocs - 1) {
42                 MPI_Send(&num, 1, MPI_INT, myid + 1, 0, MPI_COMM_WORLD);
43                 cout << myid << " send " << num << " to " << myid + 1 << endl;
44             }
45         }
46         MPI_Barrier(MPI_COMM_WORLD); // wait all pro finish
47     } while (num > 0);
48 
49     MPI_Finalize();
50 
51     return 0;
52 }

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

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