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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <mpi.h>
#define DATASIZE 64
#define WRITER_ID 0
void single_reader(int, int *, int);
void ordered_print(int, int, int *, int);
int main(int argc, char *argv[])
{
int my_id, ntasks, localsize;
int *localvector;
MPI_Init(&argc, &argv);
MPI_Comm_size(MPI_COMM_WORLD, &ntasks);
MPI_Comm_rank(MPI_COMM_WORLD, &my_id);
if (ntasks > 64) {
fprintf(stderr, "Datasize (64) should be divisible by number "
"of tasks.\n");
MPI_Abort(MPI_COMM_WORLD, EXIT_FAILURE);
}
if (DATASIZE % ntasks != 0) {
fprintf(stderr, "Datasize (64) should be divisible by number "
"of tasks.\n");
MPI_Abort(MPI_COMM_WORLD, EXIT_FAILURE);
}
localsize = DATASIZE / ntasks;
localvector = (int *) malloc(localsize * sizeof(int));
single_reader(my_id, localvector, localsize);
ordered_print(ntasks, my_id, localvector, localsize);
free(localvector);
MPI_Finalize();
return 0;
}
void single_reader(int my_id, int *localvector, int localsize)
{
FILE *fp;
int *fullvector, nread;
char *fname = "singlewriter.dat";
/* TODO: Implement a function that will read the data from a file so that
a single process does the file io. Use rank WRITER_ID as the io rank */
free(fullvector);
}
/* Try to avoid this type of pattern when ever possible.
Here we are using this serialized output just to make the
debugging easier. */
void ordered_print(int ntasks, int rank, int *buffer, int n)
{
int task, i;
for (task = 0; task < ntasks; task++) {
if (rank == task) {
printf("Task %i received:", rank);
for (i = 0; i < n; i++) {
printf(" %2i", buffer[i]);
}
printf("\n");
}
MPI_Barrier(MPI_COMM_WORLD);
}
}