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4 years ago
#include "mpi.h"
#include <stdio.h>
#define NELEM 25
int main(argc,argv)
int argc;
char *argv[];
{
int numtasks, rank, source=0, dest, tag=1, i;
typedef struct {
float x, y, z;
float velocity;
int n, type;
} Particle;
Particle p[NELEM], particles[NELEM];
MPI_Datatype particletype, oldtypes[2];
int blockcounts[2];
/* MPI_Aint type used to be consistent with syntax of */
/* MPI_Type_extent routine */
MPI_Aint offsets[2], extent;
MPI_Status stat;
MPI_Init(&argc,&argv);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &numtasks);
/* Setup description of the 4 MPI_FLOAT fields x, y, z, velocity */
offsets[0] = 0;
oldtypes[0] = MPI_FLOAT;
blockcounts[0] = 4;
/* Setup description of the 2 MPI_INT fields n, type */
/* Need to first figure offset by getting size of MPI_FLOAT */
MPI_Type_extent(MPI_FLOAT, &extent);
offsets[1] = 4 * extent;
oldtypes[1] = MPI_INT;
blockcounts[1] = 2;
/* Now define structured type and commit it */
MPI_Type_struct(2, blockcounts, offsets, oldtypes, &particletype);
MPI_Type_commit(&particletype);
/* Initialize the particle array and then send it to each task */
if (rank == 0) {
for (i=0; i<NELEM; i++) {
particles[i].x = i * 1.0;
particles[i].y = i * -1.0;
particles[i].z = i * 1.0;
particles[i].velocity = 0.25;
particles[i].n = i;
particles[i].type = i % 2;
}
for (i=0; i<numtasks; i++)
MPI_Send(particles, NELEM, particletype, i, tag, MPI_COMM_WORLD);
}
MPI_Recv(p, NELEM, particletype, source, tag, MPI_COMM_WORLD, &stat);
/* Print a sample of what was received */
printf("rank= %d %3.2f %3.2f %3.2f %3.2f %d %d\n", rank,p[3].x,
p[3].y,p[3].z,p[3].velocity,p[3].n,p[3].type);
MPI_Finalize(); }