[mpich-discuss] Matrix dimension

[Alejandro Allievi]

Hi,

The following matrix multiplication code does not execute in my
machine for MATRIX_ORDER greater than 400 or so, and I've got plenty
of memory. Is there anything I need to tweak in MPI.h for this to
work??

Thanks for any help.

Alejandro

#include <stdio.h>
#include "mpi.h"        /* for the Wtime() function only */

#define MATRIX_ORDER 400

typedef float MATRIX_T[MATRIX_ORDER][MATRIX_ORDER];

void serial_matrix_mult(MATRIX_T A, MATRIX_T B, MATRIX_T C, int n);

int main(int argc, char* argv[])
        {
         MATRIX_T A;
         MATRIX_T B;
         MATRIX_T C;
         int i, j;
         double start, finish;
         int p, my_rank;

         MPI_Init(&argc,&argv);
         MPI_Comm_size(MPI_COMM_WORLD, &p);
         MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);

         for (i = 0; i < MATRIX_ORDER; i++)        /* initialize matrices     */
                for (j = 0; j < MATRIX_ORDER; j++) /* to an arbitrary value   */
                        {
                         A[i][j] = 5;
                         B[i][j] = 5;
                        }

         start = MPI_Wtime();
         serial_matrix_mult(A, B, C, MATRIX_ORDER);
         finish = MPI_Wtime();

         printf("Elapsed time in seconds is %e\n", finish - start );

         MPI_Finalize();

        }