Advertisement
Not a member of Pastebin yet?
Sign Up,
it unlocks many cool features!
- /**********************************************************************
- * MPI-based matrix multiplication AxB=C
- *********************************************************************/
- #include <stdio.h>
- #include "mpi.h"
- #define N 4 /* number of rows and columns in matrix */
- MPI_Status status;
- double a[N][N],b[N][N],c[N][N];
- main(int argc, char **argv)
- {
- int numtasks,taskid,numworkers,source,dest,rows,offset,i,j,k;
- struct timeval start, stop;
- MPI_Init(&argc, &argv);
- MPI_Comm_rank(MPI_COMM_WORLD, &taskid);
- MPI_Comm_size(MPI_COMM_WORLD, &numtasks);
- numworkers = numtasks-1;
- /*---------------------------- master ----------------------------*/
- if (taskid == 0) {
- for (i=0; i<N; i++) {
- for (j=0; j<N; j++) {
- a[i][j]= 1.0;
- b[i][j]= 2.0;
- }
- }
- gettimeofday(&start, 0);
- /* send matrix data to the worker tasks */
- rows = N/numworkers;
- offset = 0;
- for (dest=1; dest<=numworkers; dest++)
- {
- MPI_Send(&offset, 1, MPI_INT, dest, 1, MPI_COMM_WORLD);
- MPI_Send(&rows, 1, MPI_INT, dest, 1, MPI_COMM_WORLD);
- MPI_Send(&a[offset][0], rows*N, MPI_DOUBLE,dest,1, MPI_COMM_WORLD);
- MPI_Send(&b, N*N, MPI_DOUBLE, dest, 1, MPI_COMM_WORLD);
- offset = offset + rows;
- }
- /* wait for results from all worker tasks */
- for (i=1; i<=numworkers; i++)
- {
- source = i;
- MPI_Recv(&offset, 1, MPI_INT, source, 2, MPI_COMM_WORLD, &status);
- MPI_Recv(&rows, 1, MPI_INT, source, 2, MPI_COMM_WORLD, &status);
- MPI_Recv(&c[offset][0], rows*N, MPI_DOUBLE, source, 2, MPI_COMM_WORLD, &status);
- }
- gettimeofday(&stop, 0);
- printf("Here is the result matrix:\n");
- for (i=0; i<N; i++) {
- for (j=0; j<N; j++)
- printf("%6.2f ", c[i][j]);
- printf ("\n");
- }
- fprintf(stdout,"Time = %.6f\n\n",
- (stop.tv_sec+stop.tv_usec*1e-6)-(start.tv_sec+start.tv_usec*1e-6));
- }
- /*---------------------------- worker----------------------------*/
- if (taskid > 0) {
- source = 0;
- MPI_Recv(&offset, 1, MPI_INT, source, 1, MPI_COMM_WORLD, &status);
- MPI_Recv(&rows, 1, MPI_INT, source, 1, MPI_COMM_WORLD, &status);
- MPI_Recv(&a, rows*N, MPI_DOUBLE, source, 1, MPI_COMM_WORLD, &status);
- MPI_Recv(&b, N*N, MPI_DOUBLE, source, 1, MPI_COMM_WORLD, &status);
- /* Matrix multiplication */
- for (k=0; k<N; k++)
- for (i=0; i<rows; i++) {
- c[i][k] = 0.0;
- for (j=0; j<N; j++)
- c[i][k] = c[i][k] + a[i][j] * b[j][k];
- }
- MPI_Send(&offset, 1, MPI_INT, 0, 2, MPI_COMM_WORLD);
- MPI_Send(&rows, 1, MPI_INT, 0, 2, MPI_COMM_WORLD);
- MPI_Send(&c, rows*N, MPI_DOUBLE, 0, 2, MPI_COMM_WORLD);
- }
- MPI_Finalize();
- }
Advertisement
Add Comment
Please, Sign In to add comment
Advertisement