data.c

mpi编程

#include <stdio.h>
#include "mpi.h"
int main( argc, argv )
int argc;
char **argv;
{
	int rank, value, size;
	MPI_Status status;
	MPI_Init( &argc, &argv );
	MPI_Comm_rank( MPI_COMM_WORLD, &rank );
	MPI_Comm_size( MPI_COMM_WORLD, &size );
	/* 得到当前进程标识和总的进程个数*/
	do {
		/* 循环执行直到输入的数据为负时才退出*/
		if (rank == 0) {
			fprintf(stderr, "\nPlease give new value=");
			/*进程0读入要传递的数据*/
			scanf( "%d", &value );
			fprintf(stderr,"%d read <-<- (%d)\n",rank,value);
			if (size>1) {
				MPI_Send( &value, 1, MPI_INT, rank + 1, 0, MPI_COMM_WORLD );
				fprintf(stderr,"%d send (%d)->-> %d\n",
					rank,value,rank+1);
				/* 若不少于一个进程则向下一个进程传递该数据*/
			}
		}
		else {
			MPI_Recv( &value, 1, MPI_INT, rank - 1, 0, MPI_COMM_WORLD,&status );
			/* 其它进程从前一个进程接收传递过来的数据*/
			fprintf(stderr,"%d receive (%d)<-<- %d\n",rank,value,rank-1);
			if (rank < size - 1) 
			{
				MPI_Send( &value, 1, MPI_INT, rank + 1, 0, MPI_COMM_WORLD );
				fprintf(stderr,"%d send (%d)->-> %d\n",rank,value,rank+1);
				/*若当前进程不是最后一个进程则将该数据继续向后传递*/
			}
		}
		MPI_Barrier(MPI_COMM_WORLD);
		/* 执行一下同步加入它主要是为了将前后两次数据传递分开*/
	} while ( value>=0);
	MPI_Finalize( );
}