/* test of MPI */

#include "mpi.h"
#include <stdio.h>
#include <string.h>
#include <unistd.h>

int main(int argc, char **argv) {
	char idstr[2232]; char buff[22128];
	char processor_name[MPI_MAX_PROCESSOR_NAME];
	int numtask,rank; int i,j; int namelen;
	MPI_Status stat;

	printf("argc=%2d argv=%p\n",argc,argv);
	for (i=0;i<argc;i++) {
		printf("  i=%2d[%2d]   argv[i]=|%s|\n",i,argc,argv[i]);
	}
	printf("before 'MPI_Init(&argc,&argv)'\n");
	int rc=MPI_Init(&argc,&argv);
	printf("rc=%d   MPI_SUCCESS=%d\n",rc,MPI_SUCCESS);
	if (rc != MPI_SUCCESS) {
		printf("Error starting MPI programm. Terminating.\n");
		MPI_Abort(MPI_COMM_WORLD, rc);
	}
	MPI_Comm_size(MPI_COMM_WORLD,&numtask);
	MPI_Comm_rank(MPI_COMM_WORLD,&rank);
	MPI_Get_processor_name(processor_name, &namelen);
 
	printf("Hello, world.  I am %d of %d on %s\n", rank,numtask,processor_name);
	fflush(stdout);

	if(rank == 0) {
		printf("WE have %d processes\n", numtask);
		for(i=1;i<numtask;i++) {
			sprintf(buff, "Hello %d", i);
			MPI_Send(buff, 128, MPI_CHAR, i, 0, MPI_COMM_WORLD);
			sleep(1);
		}
		for(j=1;j<numtask;j++) {
      MPI_Recv(buff, 128, MPI_CHAR, j, 0, MPI_COMM_WORLD, &stat);
      printf("%s\n", buff);
			sleep(1);
    }
	} else {
		MPI_Recv(buff, 128, MPI_CHAR, 0, 0, MPI_COMM_WORLD, &stat);
		sprintf(idstr, " Processor %d at node %s ", rank, processor_name);
		strcat(buff, idstr);
		strcat(buff, "reporting for duty\n");
		MPI_Send(buff, 128, MPI_CHAR, 0, 0, MPI_COMM_WORLD);
		sleep(1);
	}  

	printf("rank=%2d  numtask=%2d   processor_name=%s, before 'sleep(%d)'\n",
				 rank,numtask,processor_name,5*numtask);
	sleep(5*numtask);
	printf("rank=%2d  numtask=%2d   processor_name=%s, after  'sleep(%d)'\n",
				 rank,numtask,processor_name,5*numtask);
	sleep(10);
	printf("rank=%2d,  before 'MPI_Finalize'\n",rank);

	MPI_Finalize();
}