Sample answer of the first exercise. (1) #include <stdio.h> #include <stdlib.h> #include <sys/time.h> #include "mpi.h" int main(int argc, char *argv[]) { int r, myid, procs; struct timeval tv; MPI_Init(&argc, &argv); MPI_Comm_rank(MPI_COMM_WORLD, &myid); MPI_Comm_size(MPI_COMM_WORLD, &procs); if(myid==0){ result = (int *)malloc(sizeof(int)*procs); if( result == NULL){ printf("Not enough memory\n"); exit(EXIT_FAILURE); } gettimeofday(&tv, NULL); srand(tv.tv_usec); r = rand(); MPI_Gather(&r,1,MPI_INT,result,1,MPI_INT,0,MPI_COMM_WORLD); if(myid == 0){ for(i=0;i < procs ;i++){ printf("%d: %d\n",i, result[i]); free(result); MPI_Finalize();

Sample answer of the first exercise. (2) #include <stdio.h> #include <stdlib.h> #include <sys/time.h> #include "mpi.h" int main(int argc, char *argv[]) { int r, myid, procs; struct timeval tv; MPI_Init(&argc, &argv); MPI_Comm_rank(MPI_COMM_WORLD, &myid); MPI_Comm_size(MPI_COMM_WORLD, &procs); gettimeofday(&tv,NULL); srand(tv.tv_usec); r = rand(); if (myid != 0) MPI_Recv(&val,1,MPI_INT,myid-1,0,MPI_COMM_WORLD,&status); printf("%d: %d\n",myid,r); if (myid !=procs-1) MPI_Send(&val,1,MPI_INT,myid+1,0,MPI_COMM_WORLD); MPI_Finalize(); }