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/* Copyright (c) 2009-2018. The SimGrid Team.
* All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
* under the terms of the license (GNU LGPL) which comes with this package. */
/* This example should be instructive to learn about SMPI_SHARED_CALL */
#include <stdio.h>
#include <mpi.h>
#include <stdint.h>
#include <inttypes.h>
static void* hash(const char *str, uint64_t* ans)
{
const char *tohash = str;
*ans=5381;
printf("hashing !\n");
int c = *tohash;
while (c != 0) {
*ans = ((*ans << 5) + *ans) + c; /* hash * 33 + c */
tohash++;
c = *tohash;
}
return NULL;
}
int main(int argc, char *argv[])
{
MPI_Init(&argc, &argv);
int rank;
int size;
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &size);
//Let's Allocate a shared memory buffer
uint64_t* buf = SMPI_SHARED_MALLOC(sizeof(uint64_t));
//one writes data in it
if(rank==0){
*buf=size;
}
MPI_Barrier(MPI_COMM_WORLD);
//everyone reads from it.
printf("[%d] The value in the shared buffer is: %" PRIu64"\n", rank, *buf);
MPI_Barrier(MPI_COMM_WORLD);
//Try SMPI_SHARED_CALL function, which should call hash only once and for all.
static const char str[] = "onceandforall";
if(rank==size-1){
SMPI_SHARED_CALL(hash,str,str,buf);
}
MPI_Barrier(MPI_COMM_WORLD);
printf("[%d] After change, the value in the shared buffer is: %" PRIu64"\n", rank, *buf);
SMPI_SHARED_FREE(buf);
MPI_Finalize();
return 0;
}
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