matrix_multiply.c

一个计算矩阵乘的程序,程序很简单,请大家帮忙检查下

#include "mpi.h"
#include <stdio.h>
//count the multiply of martrix A and B
//The number of processes of this program requires is size+1
int
main (int argc, char *argv[])
{
  int i, j, rank, size;
  float a[10][10], b[10][10], temp[10];
  MPI_Status status;
  MPI_Init (&argc, &argv);
  MPI_Comm_rank (MPI_COMM_WORLD, &rank);
  MPI_Comm_size (MPI_COMM_WORLD, &size);
  if (rank != 0)
    {
      for (i = 0; i < 10; i += 1)
	for (j = 0; j < 10; j += 1)
	  {
	    a[i][j] = 1.0;
	    b[i][j] = 1.0;
	  }
      for (i = 0; i < 10; i += 1)	//i infers the column of c, it's to say in the result martrix
	{
	  temp[i] = 0;		// the whole name is c[rank][i]
	  for (j = 0; j < 10; j += 1)	// j infers the column of a , it's to say the row of b
	    {
	      temp[i] += a[rank+1][j] * b[j][i];
	    }
	  MPI_Send (temp, 10, MPI_FLOAT, 0, rank, MPI_COMM_WORLD);
	}
    }
  else
    {
      float c[10][10];
      for (i = 0; i < 10; i += 1)
	{
	  MPI_Recv (temp, 10, MPI_FLOAT, MPI_ANY_SOURCE, MPI_ANY_TAG,
			MPI_COMM_WORLD, &status);
	  c[status.MPI_SOURCE-1][i] = temp[i];
	}
      for (i = 0; i < 10; i += 1)
	{
	  printf ("\n");
	  for (j = 0; j < 10; j += 1)
	    printf ("%f ", c[i][j]);
	}
    }
  MPI_Finalize ();
}