Using MPI with a .sh script?

Question

I have a runPR.sh script as below

DIR=/directory/buildagain/bin/Project
 FILELIST=$1

 while read FILE
 do
     echo "Processing ${FILE}..."
     ./makeInp.sh ${FILE} ${FILE} >INP/${FILE}.inp
     ${DIR} -PR INP/${FILE}.inp
 done < ${FILELIST}

For the serial program, I run the program by typing make in /directory/buildagain and then ./runPR.sh values.txt. (values.txt just contains the line Chain)

EDIT: Here is a small portion of my code.

 int main( int argc, char *argv[ ] )
 {
      MPI_Status status;
      MPI_Init(&argc,&argv); 
      if( strcmp(argv[1],"-PR") == 0 )
           runPR(argc-2, &argv[2]);
      return 0;
 }

 int runPR(int argc, char* argv[])
 { 
      cout<<"run here"<<endl;

      int mynode, totalnodes;
      int sum,startval,endval,accum;
      int master=0;

      MPI_Comm_size(MPI_COMM_WORLD, &totalnodes); // get totalnodes
      MPI_Comm_rank(MPI_COMM_WORLD, &mynode); // get mynode

      PROpt opt;
      Solve* ps = new Solve();
      cout<<"here1"<<endl;

      cout<<"total nodes "<<totalnodes<<endl;
      for(int j=0;j<totalnodes-1;j=j+1){

           cout<<"processor"<<mynode<<"  received from "<<j<<endl;

           ps->getFile(&opt,argv[0]);
      }
 }

By typing mpirun -np 4 ../directory/buildagain/bin/Project -PR INP/Chain.inp, I see run here, here, total nodes1 printed 4 times. But I don't see cout<<"processor"<<mynode<<" received from "<<j<<endl; printed out, and I would expected total nodes to show 4, not 1. Also, the program just stops. Why is this?

Answer 1

After you reported getting output like

total nodes=1

and

This node=0 

printed out 4 times, I concluded you are trying this: mpirun -np 4 script-name.sh. It does this because mpirun is launching 4 copies of a shell script which doesn't understand MPI communication semantics.

If you can somehow get launch mpirun on a script, then remember (1) the script is running in the local "head" node environment, not the remote one, (2) the script must exec to your program as its last and final breath, and (3) when the program runs, it's in the environment on possibly another node -- possibly not having access to the files you had on the head.

So the script should look like this:

PROG="$1"; shift;
OPT="$2"; shift    
for FILE in "$@"
do
     echo "Processing ${FILE}..."
     ./makeInp.sh ${FILE} ${FILE} >INP/${FILE}.inp
done
exec $PROG $OPT "$@"

Within PROG, you'll have to index ARGV to correspond to the current node/thread. (Do check that you haven't exceeded argc or you'll get a NULL-pointer violation.) I don't think there's another/better way.