In the given example two N * N matrix will be multiplied and given the output matrix.

You can Download Code From

**HERE**

Execute the code using following commands

**To Compile**

[aruna@ubuntu]~$

**mpicc -o matrix matrix.c**

To Run the Code

To Run the Code

[aruna@ubuntu]~$

**mpirun -np 4 matrix**(here -np argument means the number of workers that we are going to use)

/********************************************************************** Message Parsing Interface (MPI) Matrix Multiplication A*B = C *********************************************************************/ #include "stdio.h" #include "mpi.h" #define N 500 /* number of rows and columns in matrix */ MPI_Status status; double a[N][N],b[N][N],c[N][N]; //matrix used main(int argc, char **argv){ struct timeval start, stop; int numberOfTasks, mtype, taskID, numberOfWorkers, source, destination, rows, averageRow, extra, offset,i,j,k; //first initialization MPI_Init(&argc, &argv); MPI_Comm_rank(MPI_COMM_WORLD, &taskID); MPI_Comm_size(MPI_COMM_WORLD, &numberOfTasks); numberOfWorkers = numberOfTasks-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; } } /* send matrix data to the worker tasks */ gettimeofday(&start, 0); averageRow = N/numberOfWorkers; //average rows per worker extra= N%numberOfWorkers; //extra rows offset = 0; for (destination=1; destination<=numberOfWorkers; destination++){ if(destination<=extra){ rows = averageRow+1; }else{ rows = averageRow; } mtype = 1; MPI_Send(&offset, 1, MPI_INT, destination, mtype, MPI_COMM_WORLD); MPI_Send(&rows, 1, MPI_INT, destination, mtype, MPI_COMM_WORLD); MPI_Send(&a[offset][0], rows*N, MPI_DOUBLE,destination,mtype, MPI_COMM_WORLD); MPI_Send(&b, N*N, MPI_DOUBLE, destination, mtype, MPI_COMM_WORLD); offset = offset + rows; } /* wait for results from all worker tasks */ for (i=1; i<=numberOfWorkers; i++){ mtype = 2; source = i; MPI_Recv(&offset, 1, MPI_INT, source, mtype, MPI_COMM_WORLD, &status); MPI_Recv(&rows, 1, MPI_INT, source, mtype, MPI_COMM_WORLD, &status); MPI_Recv(&c[offset][0], rows*N, MPI_DOUBLE, source, mtype, MPI_COMM_WORLD, &status); } gettimeofday(&stop, 0); printf("Upper Left = %6.2f Upper Right = %6.2f \n",c[0][0],c[0][N-1]); printf("Lower Left = %6.2f Lower Right = %6.2f \n",c[N-1][0],c[N-1][N-1]); 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; mtype = 1; MPI_Recv(&offset, 1, MPI_INT, source, mtype, MPI_COMM_WORLD, &status); MPI_Recv(&rows, 1, MPI_INT, source, mtype, MPI_COMM_WORLD, &status); MPI_Recv(&a, rows*N, MPI_DOUBLE, source, mtype, MPI_COMM_WORLD, &status); MPI_Recv(&b, N*N, MPI_DOUBLE, source, mtype, 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]; } mtype = 2; MPI_Send(&offset, 1, MPI_INT, 0, mtype, MPI_COMM_WORLD); MPI_Send(&rows, 1, MPI_INT, 0, mtype, MPI_COMM_WORLD); MPI_Send(&c, rows*N, MPI_DOUBLE, 0, mtype, MPI_COMM_WORLD); } MPI_Finalize(); }

By the way to prepare the running environment please refer this site.. http://www.lam-mpi.org/

If you have anything to clarify. Please Drop a comment.. :)