#include <stdlib.h>
#include <stdio.h>
#include "pvm3.h"
#define SLAVEMAX 32

int main(void){
  int mytid;             /* my task id */
  int tids[SLAVEMAX];    /* task ids   */
  int n, me, i, nproc, master, msgtype;
  float data[100], result;
  float work();
  mytid = pvm_mytid();
  /* Receive data from master */
  msgtype = 0;
  pvm_recv( -1, msgtype );
  pvm_upkint(&nproc, 1, 1);
  pvm_upkint(tids, nproc, 1);
  pvm_upkint(&n, 1, 1);
  pvm_upkfloat(data, n, 1);
  /* Determine which slave I am (0 -- nproc-1) */
  for( i=0; i<nproc ; i++ )
    if( mytid == tids[i] ){ me = i; break; }
  /* Do calculations with data */
  result = work( me, n, data, tids, nproc );
  /* Send result to master */
  pvm_initsend( PvmDataDefault );
  pvm_pkint( &me, 1, 1 );
  pvm_pkfloat( &result, 1, 1 );
  msgtype = 5;
  master = pvm_parent();
  pvm_send( master, msgtype );
  /* Program finished. Exit PVM before stopping */
  pvm_exit();
  exit(EXIT_SUCCESS);
}

float work(int me, int n, float *data, int *tids, int nproc){
     /* Simple example: slaves exchange data with left neighbor (wrapping) */
  int i, dest;
  float psum = 0.0;
  float sum = 0.0;
  for( i=0 ; i<n ; i++ ){
    sum += me * data[i];
  }
  /* illustrate node-to-node communication */
  pvm_initsend( PvmDataDefault );
  pvm_pkfloat( &sum, 1, 1 );
  dest = me+1;
  if( dest == nproc ) dest = 0;
  pvm_send( tids[dest], 22 );
  pvm_recv( -1, 22 );
  pvm_upkfloat( &psum, 1, 1 );
  return( sum+psum );
}