[Condor-users] Question for MPI gurus

["Junaid N. Sahibzada" <sjunaidn@xxxxxxxxx>]

I have the following simple programs
  
#include "mpi.h"
#include <stdio.h>
   

/* problem parameters */

#define f(x)            ((x) * (x))
#define numberRects     50
#define lowerLimit      2.0
#define upperLimit      5.0

   

int main( int argc, char * argv[  ] )

{

   /* MPI variables */
   int dest, noProcesses, processId, src, tag;
   MPI_Status status;

   

   /* problem variables */
   int   i;
   double area, at, height, lower, width, total, range;

   

   /* MPI setup */
   MPI_Init(&argc, &argv);
   MPI_Comm_size(MPI_COMM_WORLD, &noProcesses);
   MPI_Comm_rank(MPI_COMM_WORLD, &processId);

   

   /* adjust problem size for subproblem*/
   range = (upperLimit - lowerLimit) / noProcesses;
   width = range / numberRects;
   lower = lowerLimit + range * processId;

   

   !
 /*
 calculate area for subproblem */
   area = 0.0;
   for (i = 0; i < numberRects; i++)
   {  at = lower + i * width + width / 2.0;
      height = f(at);
      area = area + width * height;
   }

   

   /* collect information and print results */
   tag = 0;
   if (processId = = 0)         /* if rank is 0, collect results */

   {  total = area;
      for (src="" src < noProcesses; src++)
      {  MPI_Recv(&area, 1, MPI_DOUBLE, src, tag, MPI_COMM_WORLD, &status);
         total = total + area;
      }

      fprintf(stderr, "The area from %f to %f is: %f\n",
              lowerLimit, upperLimit, total );

   } 

   else                        /* all other processes only send */

   {  dest = 0; 
      MPI_Send(&area, 1, MPI_DOUBLE, dest, tag, MPI_COMM_WORLD);
   };
   

   /* finish */
   MPI_Finalize( );
   return 0;
}

Now this is a s!
 imple MPI
 program which calculates the 
area between a given set of numbers.


the program when run under MPI is uploaded to each node 
that is going to execute it and then the results 
are returned back. 

Is it possible that i write two different programs. upload
them with a single  mpi command. they run simultaneously
on different nodes and yet they compute the same problem that
is calculating the area of a given region.

what i am emphasising is that two different programs working
on the same problem and combining their results.

in the example above the program is the same but different 
nodes execute different pieces of the same code using conditional
statements?

so in reality the job distribution is being done by the programmer
himself. while MPI is just uploading the copy of the executable
to different nodes. 

the question once again: Is it possible to run two different 
pieces of code/two different !
 programs
 using MPI and yet those
two programs work on the same problem.

I would appreciate an example.

regards

programs

Junaid N. Sahibzada

Cell # (+61) 404 998 494 

284/9 Crystal St. Waterloo, 2017, NSW, Australia

International Student MSc Internetworking, UTS, Australia

Bachelor of Information Technology, NUST, Pakistan

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