[MPICH] Help with a problematic simple MPI application that creates directories

[Clements, Brent]

Ok, the goal of the mpi application is to take 3 arguments.... -a NUMBER
of Directories to create -b the number of files to create in each
directory -c the /basedir to use as the directory creation point.

 

I have written this mpi application and I'm at a point where I'm trying
to debug why the individual slave mpi processes aren't actually
performing the mkdir. 

 

I've attached the source to this email if someone wouldn't mind taking a
peek and seeing what I'm doing wrong. 

 

To compile just type

Mpicc -DDEBUG test4.c -o test4

 

To run the app just do mpirun -np 3 ./test4 -a 3 -c /tmp

 

The arguments don't really do anything yet(but you need them to run the
app), since in the code I have some hard coded values.

 

My problem is the "mkdir" part of the code...it never makes the
directory

 

I'd appreciate anyones help with this!!

 

I have a $25.00 gift certificate to Thinkgeek to anyone that can help me
out and point out my probably stupid mistake.

 

Btw, don't snicker, YES THE CODE IS BAD, I just need something as a
proof of concept for my relearning of MPI and I've been fighting this
thing for the past 2 hours.

 

Thanks,

BC

 

SOURCE CODE BELOW:

 

#include <stdio.h>  /* all IO stuff lives here */

#include <stdlib.h> /* exit lives here */

#include <unistd.h> /* getopt lives here */

#include <errno.h>  /* UNIX error handling lives here */

#include <string.h> /* strcpy lives here */

#include <mpi.h>    /* MPI and MPI-IO live here */

#include <sys/stat.h>

 

#define MASTER_RANK 0

#define TRUE 1

#define FALSE 0

#define BOOLEAN int

 

int main( argc, argv )

    int argc;

    char * argv [];

    {

    /* my variables */

 

    int my_rank, i, numdirs, numfiles, pool_size;

    BOOLEAN i_am_the_master = FALSE, input_error = FALSE;

    char * basedir;

    char * dir_name = NULL;

    char rankdirname[300];

 

    /* getopt variables */

 

    extern char* optarg;

    int c;

 

    /* error handling variables */

 

    extern int errno;

 

    /* ACTION */

 

    MPI_Init(&argc, &argv);

    MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);

    MPI_Comm_size(MPI_COMM_WORLD, &pool_size);

 

    if (my_rank == MASTER_RANK)

        i_am_the_master = TRUE;

 

    if (i_am_the_master)

        {

 

        /* read the command line */

 

        while ((c = getopt(argc, argv, "a:b:c:")) != -1)

            switch( c )

                {

                case 'a':

                    numdirs = atoi(optarg);

                    break;

 

                case 'b':

                    numfiles = atoi(optarg);

                    break;

 

                case 'c':

                    basedir = optarg;

                    break;

 

                case '?':

                    return 1;

 

                default:

                    abort();

                }

 

#ifdef DEBUG

 

        printf("basedirname         = %s\n", basedir);

        printf("number_of_directorys  = %d\n", numdirs);

 

#endif

 

        } /* end of if(i_am_the_master) { <read the command line> } */

 

    /* Transmit the effect of reading the command line to other

       processes. */

 

 

    /* If we managed to get here, data read from the command line

       is probably OK. */

    MPI_Bcast(&basedir, sizeof(basedir), MPI_CHAR, MASTER_RANK,
MPI_COMM_WORLD);

    MPI_Bcast(&numdirs, 1, MPI_INT, MASTER_RANK, MPI_COMM_WORLD);

 

    if (!i_am_the_master)

        {

 

        /* Now every process creates its own directory based upon its
own rank */

 

        /* PROBLEMATIC CODE */

        basedir = "/tmp";

        // Create this processes directory name based upon it's rank

        sprintf(rankdirname, "RANK%d", my_rank);

        // Change to the base dir /tmp

        chdir(basedir);

        // make the directory

        mkdir(rankdirname, S_IRWXU);

        printf("Creating Directory: %s/%s\n", basedir, rankdirname);

        /* PROBLEMATIC CODE */

 

 

        printf("number_of_directorys  = %d\n", numdirs);

 

        printf("MY RANK = %d\n", my_rank);

        }

    else

        {

        printf("MY RANK = %d\n", my_rank);

        }

 

    MPI_Finalize();

    exit(0);

    }




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