/* parallel Monte Carlo area calculation */
/* slave program for fourth quadrant */

#include <stdio.h>
#include <math.h>
#include <pvm3.h>
#define steps 50000
#define xmin -0.5
#define xmax 0.0
#define ymin 0.0
#define ymax 0.5

double f(double x)			/* the function for the */
{					/* border in this quadrant */
   return(sqrt(0.25-x*x));
}

main()
{
int i, hit=0, ptid, bufid, dum, send[1], type;
double x, y;

srand48(pvm_mytid());			/* seed the number generator */
					/* not a good way of doing it */
ptid = pvm_parent();


do
{
   send[0]=0;
   for (i=1; i <= steps; i++)
   {
      x= drand48()*(xmax+xmin);		/* random points in the */
      y= drand48()*(ymax+ymin);		/* quadrant */
      if (f(x) <=y ) send[0]++;     		/* point is inside the figure */
   }     
   pvm_initsend(PvmDataDefault);		/* send result back to master */
   pvm_pkint(send, 1, 1);
   pvm_send(ptid, 4);
   bufid=pvm_recv(ptid, -1);			/* any message from master */
   pvm_bufinfo(bufid, &dum, &type, &dum);	/* more work ? */
}while(type);

pvm_exit;  					/* type=0 means we are done */ 
}