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/***************************************************************************/
/* ____Demonstrates passing a stream to another process____ */
/* Process 0 initializes a random number stream and prints a few random */
/* numbers. It then passes this stream to process 1, which recieves it */
/* and prints a few random numbers from this stream. */
/***************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <mpi.h> /* MPI header file */
/* Uncomment the following line to get the interface with pointer checking */
/*#define CHECK_POINTERS */
#include "sprng.h" /* SPRNG header file */
#define SEED 985456376
main(int argc, char *argv[])
{
int streamnum, nstreams, *stream;
double rn;
int i, myid, nprocs, len;
MPI_Status status;
char *packed;
int gtype; /*--- */
/************************** MPI calls ************************************/
MPI_Init(&argc, &argv); /* Initialize MPI */
MPI_Comm_rank(MPI_COMM_WORLD, &myid); /* find process id */
MPI_Comm_size(MPI_COMM_WORLD, &nprocs); /* find number of processes */
if(nprocs < 2)
{
fprintf(stderr,"ERROR: At least 2 processes required\n");
MPI_Finalize();
exit(1);
}
/*--- node 0 is reading in a generator type */
if(myid == 0)
{
#include "gen_types_menu.h"
printf("Type in a generator type (integers: 0,1,2,3,4,5): ");
scanf("%d", >ype);
}
MPI_Bcast(>ype,1,MPI_INT,0,MPI_COMM_WORLD ); /*--- broadcast gen type */
if (myid==0) /*********** process 0 sends stream to process 1 **********/
{
streamnum = 0;
nstreams = 1;
stream = init_sprng(gtype,streamnum,nstreams,SEED,SPRNG_DEFAULT);/*initialize stream*/
printf("\n\nProcess %d: Print information about stream:\n",myid);
print_sprng(stream);
printf("Process %d: Print 2 random numbers in [0,1):\n", myid);
for (i=0;i<2;i++)
{
rn = sprng(stream); /* generate double precision random number */
printf("Process %d: %f\n", myid, rn);
}
len = pack_sprng(stream, &packed); /* pack stream into an array */
/* inform process 1 how many bytes process 0 will send. */
MPI_Send(&len, 1, MPI_INT, 1, 0, MPI_COMM_WORLD);
MPI_Send(packed, len, MPI_BYTE, 1, 0, MPI_COMM_WORLD); /* send stream */
free(packed); /* free storage for array */
nstreams = free_sprng(stream);
printf(" Process 0 sends stream to process 1\n");
printf(" %d generators now exist on process 0\n", nstreams);
}
else if(myid == 1) /***** process 1 receives stream from process 0 ******/
{
MPI_Recv(&len, 1, MPI_INT, 0, MPI_ANY_TAG,
MPI_COMM_WORLD, &status); /* receive buffer size required */
if ((packed = (char *) malloc(len)) == NULL) /* allocate array */
{
fprintf(stderr,"ERROR: process %d: Cannot allocate memory\n", myid);
MPI_Finalize();
exit(1);
}
MPI_Recv(packed, len, MPI_BYTE, 0, MPI_ANY_TAG,
MPI_COMM_WORLD, &status); /* receive packed stream */
stream = unpack_sprng(packed); /* unpack stream */
printf(" Process 1 has received the packed stream\n");
printf("Process %d: Print information about stream:\n",myid);
print_sprng(stream);
free(packed); /* free array of packed stream */
printf(" Process 1 prints 2 numbers from received stream:\n");
for (i=0;i<2;i++)
{
rn = sprng(stream); /* generate double precision random number */
printf("Process %d: %f\n", myid, rn);
}
free_sprng(stream); /* free memory used to store stream state */
}
MPI_Finalize(); /* terminate MPI */
}
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