hi,
I ran a matrix multiplication program on two machines seperately and it
worked.
Later I ran the same program on the same machines concurrently and it
didn't work.
Can anyone give me some hint?
---------------------------------------------------------------------------
matrix multiplication program code:
#include <mpi.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MASTER 0 // taskid of first task
#define FROM_MASTER 1 // setting a message type
#define FROM_WORKER 2 // setting a message type
int main(int argc, char *argv[]) {
int N[3], // N[0]: number of rows of matrix A
// N[1]: number of columns of matrix A
// N[2]: number of columns of matrix B
numtasks, // number of tasks
taskid, // task identifier
source, // task id of message source
dest, // task id of message destination
mtype, // message type
i, j, k; // misc
double stime, etime; // start time and stop time
double **a, **b, **c; // c = a * b
int *start, *end, *row;
FILE *stream;
char line[1024], *file = "download/matrix.txt";
MPI_Status status;
stream = fopen("upload/dimension.txt", "r");
for(i=0; i<3; i++) {
fgets(line, sizeof(line), stream);
N[i] = atoi(strtok(line, " "));
}
fclose(stream);
a = (double **)malloc(N[0]*sizeof(double *));
for(i=0; i<N[0]; i++) {
a[i] = (double *)malloc(N[1]*sizeof(double));
}
b = (double **)malloc(N[1]*sizeof(double *));
for(i=0; i<N[1]; i++) {
b[i] = (double *)malloc(N[2]*sizeof(double));
}
c = (double **)malloc(N[0]*sizeof(double *));
for(i=0; i<N[2]; i++) {
c[i] = (double *)malloc(N[2]*sizeof(double));
}
MPI_Init(&argc, &argv);
MPI_Comm_size(MPI_COMM_WORLD, &numtasks);
MPI_Comm_rank(MPI_COMM_WORLD, &taskid);
start = (int *)malloc(numtasks*sizeof(int));
end = (int *)malloc(numtasks*sizeof(int));
row = (int *)malloc(numtasks*sizeof(int));
stream = fopen("upload/start.txt", "r");
for(i=0; i<numtasks; i++) {
fgets(line, sizeof(line), stream);
start[i] = atoi(strtok(line, " "));
}
fclose(stream);
stream = fopen("upload/end.txt", "r");
for(i=0; i<numtasks; i++) {
fgets(line, sizeof(line), stream);
end[i] = atoi(strtok(line, " "));
}
fclose(stream);
for(i=0; i<numtasks; i++) {
fgets(line, sizeof(line), stream);
row[i] = end[i] - start[i] + 1;
}
stime = MPI_Wtime();
if(taskid == MASTER) {
// initialize matrix a and matrix b
for(i=0; i<N[0]; i++) {
for(j=0; j<N[1]; j++) {
a[i][j] = i+j;
}
}
for(i=0; i<N[1]; i++) {
for(j=0; j<N[2]; j++) {
b[i][j] = i*j;
}
}
// send matrix data to worker processes
mtype = FROM_MASTER;
for(dest=1; dest<numtasks; dest++) {
MPI_Send(&a[start[dest]-1][0], row[dest]*N[1], MPI_DOUBLE,
dest, mtype, MPI_COMM_WORLD);
MPI_Send(&b, N[1]*N[2], MPI_DOUBLE, dest, mtype,
MPI_COMM_WORLD);
}
}
else {
// receive matrix data from master process
mtype = FROM_MASTER;
MPI_Recv(&a, row[taskid]*N[1], MPI_DOUBLE, MASTER, mtype,
MPI_COMM_WORLD, &status);
MPI_Recv(&b, N[1]*N[2], MPI_DOUBLE, MASTER, mtype,
MPI_COMM_WORLD, &status);
}
// common part for master and worker processes -- matrix calculation
for(k=0; k<N[2]; k++) {
for(i=0; i<row[taskid]; i++) {
c[i][k] = 0.0;
for(j=0; j<N[1]; j++) {
c[i][k] = c[i][k] + a[i][j]*b[j][k];
}
}
}
if(taskid == MASTER) {
// receive results from worker processes
mtype = FROM_WORKER;
for(source=1; source<numtasks; source++) {
MPI_Recv(&c[start[source]-1][0], row[source]*N[2], MPI_DOUBLE,
source, mtype, MPI_COMM_WORLD, &status);
}
}
else {
// send results to master process
mtype = FROM_WORKER;
MPI_Send(&c, row[taskid]*N[2], MPI_DOUBLE, MASTER, mtype,
MPI_COMM_WORLD);
}
etime = MPI_Wtime();
if(taskid == MASTER) {
printf("CPU time : %f\n", etime-stime);
for(i=0; i<N[0]; i++) {
for(j=0; j<N[2]; j++) {
printf("%.2f ", c[i][j]);
}
printf("\n");
}
}
free(start);
free(end);
free(row);
MPI_Finalize();
for(i=0; i<N[0]; i++) {
free(a[i]);
}
free(a);
for(i=0; i<N[1]; i++) {
free(b[i]);
}
free(b);
for(i=0; i<N[0]; i++) {
free(c[i]);
}
free(c);
return 0;
}
---------------------------------------------------------------------------
dimension.txt:
3
3
3
---------------------------------------------------------------------------
start.txt:
1
3
---------------------------------------------------------------------------
end.txt:
2
3
---------------------------------------------------------------------------
Yucheng Chou
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