/*---------------------------------------------------------------------------
/  File: manager.c
/----------------------------------------------------------------------------
/
/     This is a trivial "hello world" program for illustrating the
/     use of the SP2
/
/     One argument is used, to tell the number of processes to create.
/
/  ** Warning:  For PVMe, the argument must be less that the number
/               of available processors.
/    
/     This manager program spawns copies of the program 'worker'.
/
/----------------------------------------------------------------------------
*/

/* Contact: Karin A. Remington, karin@cam.nist.gov */

/*
/  Note: full path to pvm3.h is given in INCL compilation flag in makefile:
*/
#include "pvm3.h"

#include<stdlib.h>
#include<stdio.h>
#include<malloc.h>

main(argc, argv)
int argc; char *argv[];
{
      int *tid;
      int i;
      int noderesult;
      int type;
      int hostid, nodeid, msgid, rc;
      int nprocs, nworkers, narchs;
      struct hostinfo *hosts;
      FILE *out_file;
      char *my_hostname;
      
      nworkers = atoi(argv[1]);
/*
/     Enroll the manager program in PVM and return an id for this process...
/     and call pvmfconfig to return the # of nodes available (nprocs)...
*/
      hostid = pvm_mytid();
      pvm_config(&nprocs, &narchs, &hosts);
      if ( nworkers > nprocs - 1 ) {
         printf("Warning: If running under PVMe, too many workers have been requested.\n");
      }
/*
/     Allocate space for the array of task ids:
*/
      tid = (int *)malloc(nworkers*sizeof(int));
/*
/     Get manager hostname:
*/
      my_hostname = (char *)malloc(8);
      gethostname(my_hostname,7);
/*
/     Open the file for output
*/
      out_file = fopen("manager.results","w");
      printf("----- PVM Program manager ----\n");
      fprintf(out_file,"----- PVM Program manager ----\n");
/*
/     Spawn nworkers worker programs. Their task ids will be placed in the
/     tid array for later use in message passing.
*/
      rc = pvm_spawn("worker", (char**)0, PvmTaskDefault, "",
                                            nworkers, tid);

      if (rc != nworkers) {
         printf("Error in spawning;  Return code is %i\n",rc);
         pvm_exit();
         exit(1);
      }
/*   
/     multi-cast (broadcast) the manager hostname to all processors...
*/
      pvm_initsend(0);
      pvm_pkstr(my_hostname);
      pvm_mcast(tid, nworkers, 100);
/*
/     Send each processor an integer value to print out, modify and return.
*/
      for (i=0;i<nworkers;i++){
         pvm_initsend(0);
         pvm_pkint(&i, 1, 1);
         pvm_send(tid[i], 200);
      };
/*
/     Now, the manager receives and prints the results of the workers.
*/
      for (i=0;i<nworkers;i++){
         pvm_recv(-1, 300);
         pvm_upkint(&nodeid, 1, 1);
         pvm_upkint(&noderesult, 1, 1);
         printf("Result from task %d: %d\n",nodeid,noderesult);
         fprintf(out_file,"Result from task %d: %d\n",nodeid,noderesult);
      };

/*
/     Close the output file:
*/
      fclose(out_file);

/*
/     Call pvmfexit to terminate the PVM program gracefully...
*/
      pvm_exit();

}