You don't seem to initialize the "rows" value anywhere.
for(k=0; k<NCB; k++) {
for(i=0; i<rows; i++) {
c[i][k] = 0.0;
for(j=0; j<NCA; j++) {
c[i][k] = c[i][k] + a[i][j]*b[j][k];
}
}
}
Is "rows" supposed to be NRA?
You're most likely are walking off the end of the allocated memory.
Damien Hocking
Rome wasn’t built in a meeting.
Yu-Cheng Chou wrote:
>Hi,
>my matrix multiplication c code looks like this:
>---------------------------------------------------------------------------
>#include <mpi.h>
>#define NRA 300
>#define NCA 300
>#define NCB 300
> .
> .
> .
>int main(int argc, char *argv[]) {
> double **a, **b, **c;
> .
> .
> .
> MPI_Init(&argc, &argv);
> MPI_Comm_size(MPI_COMM_WORLD, &numtasks);
> MPI_Comm_rank(MPI_COMM_WORLD, &taskid);
> .
> .
> .
> a = (double **)malloc(NRA*sizeof(double *));
> for(i=0; i<NRA; i++) {
> a[i] = (double *)malloc(NCA*sizeof(double));
> }
>
> b = (double **)malloc(NCA*sizeof(double *));
> for(i=0; i<NCA; i++) {
> b[i] = (double *)malloc(NCB*sizeof(double));
> }
>
> c = (double **)malloc(NRA*sizeof(double *));
> for(i=0; i<NRA; i++) {
> c[i] = (double *)malloc(NCB*sizeof(double));
> }
>
> if(taskid == MASTER) {
> // initialize matrix a and matrix b
> .
> .
> .
> // send matrix data to worker processes
> .
> .
> .
> }
> else {
> // receive matrix data from master process
> .
> .
> .
> }
>
> // for both master and worker processes -- matrix calculation
> for(k=0; k<NCB; k++) {
> for(i=0; i<rows; i++) {
> c[i][k] = 0.0;
> for(j=0; j<NCA; j++) {
> c[i][k] = c[i][k] + a[i][j]*b[j][k];
> }
> }
> }
>
> if(taskid == MASTER) {
> // receive results from worker processes
> .
> .
> .
> }
> else {
> // send results to master process
> .
> .
> .
> }
>
> // free all dynamically allocated memories
> for(i=0; i<NRA; i++) {
> free(a[i]);
> }
> free(a);
>
> for(i=0; i<NCA; i++) {
> free(b[i]);
> }
> free(b);
>
> for(i=0; i<NRA; i++) {
> free(c[i]);
> }
> free(c);
>
> MPI_Finalize();
>
> return 0;
>}
>---------------------------------------------------------------------------
>
>When I run this program on two machines, error message like this came out.
>
>---------------------------------------------------------------------------
>Rank (0, MPI_COMM_WORLD): Call stack within LAM:
>MPI_Recv: process in local group is dead (rank 0, MPI_COMM_WORLD)
>Rank (0, MPI_COMM_WORLD): - MPI_Recv()
>Rank (0, MPI_COMM_WORLD): - main()
>
>One of the processes started by mpirun has exited with a nonzero exit
>code. This typically indicates that the process finished in error.
>If your process did not finish in error, be sure to include a "return
>0" or "exit(0)" in your C code before exiting the application.
>
>PID 4672 failed on node n1 (169.237.108.13) due to signal 9.
>---------------------------------------------------------------------------
>
>Any hint for that?
>
>
>
>
>_______________________________________________
>This list is archived at http://www.lam-mpi.org/MailArchives/lam/
>
>
|
