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#include <stdio.h>
#include <string.h>
#include "mpi.h"
int main(argc, argv)
int argc;
char **argv;
{
int pool_size, my_rank, destination, source, node_name_length;
char char_buffer[BUFSIZ], my_node_name[BUFSIZ], host_name[BUFSIZ];
MPI_Status status;
MPI_Init ( &argc, &argv );
/* How many processes are there in the pool? */
MPI_Comm_size ( MPI_COMM_WORLD, &pool_size );
/* What is my rank number? */
MPI_Comm_rank ( MPI_COMM_WORLD, &my_rank );
/* What is my name? */
MPI_Get_processor_name ( my_node_name, &node_name_length );
/* The rank 0 process sends its name to other processes. */
if ( my_rank == 0 ) {
strcpy (char_buffer, my_node_name);
for (destination = 1; destination < pool_size; destination++)
MPI_Send(char_buffer, strlen(my_node_name) + 1, MPI_CHAR,
destination, 1001, MPI_COMM_WORLD);
}
else {
MPI_Recv(char_buffer, BUFSIZ, MPI_CHAR, 0, 1001,
MPI_COMM_WORLD, &status);
strcpy (host_name, char_buffer);
}
/* The other processes send their names to process 0, which prints
the messages on standard output.
*/
if ( my_rank != 0 ) {
sprintf (char_buffer, "Greetings to %s from (%s, %d)",
host_name, my_node_name, my_rank);
MPI_Send (char_buffer, strlen(char_buffer) + 1, MPI_CHAR, 0,
2002, MPI_COMM_WORLD);
}
else {
for (source = 1; source < pool_size; source++) {
MPI_Recv(char_buffer, BUFSIZ, MPI_CHAR, source, 2002,
MPI_COMM_WORLD, &status);
printf ("%s\n", char_buffer);
}
}
MPI_Finalize ();
}
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