[torqueusers] unique identifiers per taks and PBS_VNODENUM?

[Andrew J Caird]

Hello,

I'm looking for a way to determine which task a given process is 
in, and it sort of looks like PBS_VNODENUM might be that, but it 
doesn't seem to be set all the time, and it seems sporadic when 
it is set.  Below is a simple code and the output from multiple 
runs.

What is PBS_VNODENUM supposed to do?

Is there an environment variable that can be read by tasks that 
can identify them uniquely?

Thanks.
--andy

#include "mpi.h"
#include <stdio.h>
#include <stdlib.h>

int main( int argc, char *argv[], char **environ)
{
     int done = 0, n, myid, numprocs, i;
     int  namelen;
     char processor_name[MPI_MAX_PROCESSOR_NAME];
     char *libpath, *p;


     MPI_Init(&argc,&argv);
     MPI_Comm_size(MPI_COMM_WORLD,&numprocs);
     MPI_Comm_rank(MPI_COMM_WORLD,&myid);
     MPI_Get_processor_name(processor_name,&namelen);

     libpath = getenv("LD_LIBRARY_PATH");
     fprintf(stderr,"Process %d on %s, LD_LIBRARY_PATH: %s\n",
             myid, processor_name,libpath);
     while ((p = *environ++)) {
         fprintf(stderr, "[%d] [%s]  %s\n",myid,processor_name,p);
     }


     exit(0);
}


[acaird at nyx301 environment-test]$ mpirun -np 8 env-m 2>&1 | grep VNODE
[0] [nyx301.engin.umich.edu]  PBS_VNODENUM=0
[7] [nyx300.engin.umich.edu]  PBS_VNODENUM=2
[2] [nyx300.engin.umich.edu]  PBS_VNODENUM=2
[acaird at nyx301 environment-test]$ mpirun -np 8 env-m 2>&1 | grep VNODE
[0] [nyx301.engin.umich.edu]  PBS_VNODENUM=0
[2] [nyx300.engin.umich.edu]  PBS_VNODENUM=2
[4] [nyx301.engin.umich.edu]  PBS_VNODENUM=0
[acaird at nyx301 environment-test]$ mpirun -np 2 env-m 2>&1 | grep VNODE
[1] [nyx301.engin.umich.edu]  PBS_VNODENUM=0
[acaird at nyx301 environment-test]$ mpirun -np 2 env-m 2>&1 | grep VNODE
[0] [nyx301.engin.umich.edu]  PBS_VNODENUM=0
[acaird at nyx301 environment-test]$ mpirun -np 2 env-m 2>&1 | grep VNODE
[1] [nyx301.engin.umich.edu]  PBS_VNODENUM=0
[acaird at nyx301 environment-test]$ mpirun -np 2 env-m 2>&1 | grep VNODE
[1] [nyx301.engin.umich.edu]  PBS_VNODENUM=0
[acaird at nyx301 environment-test]$ mpirun -np 4 env-m 2>&1 | grep VNODE
[1] [nyx301.engin.umich.edu]  PBS_VNODENUM=0
[2] [nyx300.engin.umich.edu]  PBS_VNODENUM=2