mpi_gather_mollc.c.txt

系统自带的mpi_gather函数的功能的测试程序

#include<stdio.h>
#include<mpi.h>
#include<stdlib.h>

#define SIZE 3
static int source=0;

void generate ( int *send_buffer, int size)
{
  int i;
  for (i = 0; i < size; i++)
    send_buffer[i] = i + 10;
}

int main(int argc, char **argv)
{
	int gsize, myid, i, j;
	int send_buffer[SIZE];
	int *recv_buff, *recv_buffer;
	int buff_size, tsize;

	MPI_Init(&argc, &argv);
	MPI_Comm_size(MPI_COMM_WORLD, &gsize);
	MPI_Comm_rank(MPI_COMM_WORLD, &myid);
        
	if (myid == source)  generate(send_buffer, SIZE);
	MPI_Pack_size(SIZE, MPI_INT, MPI_COMM_WORLD, &buff_size);
	recv_buff = (int *)malloc (gsize*buff_size+2*MPI_BSEND_OVERHEAD);
	if (!recv_buff)
	 {
	   printf("##### Could not allocate receive buffer of size %d", buff_size);
	   MPI_Abort(MPI_COMM_WORLD, 1);
	 }
	
	MPI_Buffer_attach(recv_buff, gsize*buff_size+2*MPI_BSEND_OVERHEAD);
	printf("Process %d is alive\n", myid);

        if (gsize != 1)
		{
			printf("######  Out of the rank!!  ######\n");
			MPI_Abort(MPI_COMM_WORLD, 1);
		}

	
	for (i = 0; i < 3; i++)
		printf("a[%d] = %d; ", i, send_buffer[i]);
	printf("\n");
        
	 MPI_Gather(&send_buffer, 3, MPI_INT, &recv_buff, 3, MPI_INT, 0, MPI_COMM_WORLD);
	 MPI_Barrier(MPI_COMM_WORLD);

	if (myid == 0)
	{
	  for (j = 0; j < 9; j++)
	  {
		printf("recv_buff[%d] = %d;", j, recv_buff[j]);
		for (i = 0; i < 3; i++)
                  printf("\n");
 	  }
	}
	MPI_Buffer_detach(&recv_buffer, &tsize);
	MPI_Finalize();
	return 0;
}