[mpich-discuss] Matrix dimension

[Pavan Balaji]

This problem has nothing to do with MPI.

You are allocating a lot of memory on the stack.  Try allocating the
matrix with a bunch of malloc's instead.

 -- Pavan

On 11/22/2012 12:35 PM US Central Time, Alejandro Allievi wrote:
> 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();
> 
>         }
> _______________________________________________
> discuss mailing list     discuss at mpich.org
> To manage subscription options or unsubscribe:
> https://lists.mpich.org/mailman/listinfo/discuss
> 

-- 
Pavan Balaji
http://www.mcs.anl.gov/~balaji