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/*
* Distributed under the OSI-approved Apache License, Version 2.0. See
* accompanying file Copyright.txt for details.
*
* Created by Dmitry Ganyushin ganyushindi@ornl.gov
*
* Helper functions for all examples
*/
#include "decomp.h"
#include "mpivars.h"
#include <mpi.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
/* random integer from {minv, minv+1, ..., maxv}
including minv and maxv */
size_t get_random(int minv, int maxv, int rank)
{
size_t n;
time_t t;
/* Intializes random number generator */
srand((unsigned)time(&t) + rank);
n = (size_t)((rand() % (maxv - minv + 1)) + minv);
return n;
}
/* gather the local sizes of arrays and sum them up
so that each process knows the global shape
and its own offset in the global space */
void gather_decomp_1d(size_t *mysize, size_t *myshape, size_t *myoffset)
{
size_t *sizes;
int i;
sizes = malloc(sizeof(size_t) * (size_t)nproc);
MPI_Allgather(mysize, 1, MPI_LONG_LONG, sizes, 1, MPI_LONG_LONG, app_comm);
*myshape = 0;
for (i = 0; i < nproc; i++)
{
*myshape += sizes[i];
}
*myoffset = 0;
for (i = 0; i < rank; i++)
{
*myoffset += sizes[i];
}
free(sizes);
return;
}
void decomp_1d(size_t *globalsize, size_t *myoffset, size_t *mysize)
{
size_t rem;
*mysize = *globalsize / nproc;
rem = *globalsize - (nproc * *mysize);
if (rank < rem)
{
*mysize = *mysize + 1;
*myoffset = rank * *mysize;
}
else
{
*myoffset = rank * *mysize + rem;
}
return;
}
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