/*  "q1_slave.txt"
 *  Question #1, Master/Slave  to add up N numbers (integers only) 
 *
 *  NOTE:  the first slave (me=0) has a value of 1
 *         the Nth slave (me=n-1) has a value of n-1
 *         so the value added to sum is always
 *         me+1.  This isn't very clear here but running behind on time.
 *
 * tjn  3:54 PM 3/2/00
 *
 *     SLAVE
 */
#include <stdio.h>
#include <pvm3.h>
#define  MAX 100

int main()
{
     int i,me,n, tids[MAX],mytid,sum;
     sum = 0;     

     mytid = pvm_mytid();
     
     pvm_recv(pvm_parent(), -1);
     pvm_upkint(&n, 1, 1);
     pvm_upkint(tids, n, 1);

     /* determine who were are */
     for(i=0; i < n; i++)
         if(mytid == tids[i])
         {
              me = i;
              break;
         }


     /* if I'm the first slave */
     if(me == 0)
     {  /* start sending, get ball rolling */
           sum = 1;
           pvm_initsend(PvmDataDefault);
           pvm_pkint(&sum, 1, 1);
           pvm_send(tids[me+1], 1);
     }
     else
     {    /* everyone else */
           pvm_recv(tids[me-1], 1);
           pvm_upkint(&sum, 1, 1);
           sum += (me+1);		
           pvm_initsend(PvmDataDefault);
           pvm_pkint(&sum, 1, 1);

           /* Checkto see if I'm the Nth (n-1) */
           if(me == n-1)
                 pvm_send(pvm_parent(), 1);	/* Nth sends to parent */
           else
                 pvm_send(tids[me+1], 1);	/* Others send to next */
     }    
     
     pvm_exit();
     return 0;
}