[mpich-devel] proper way to detect if program launched by mpiexec?

[Jeff Hammond]

I wrote a trivial program that uses MPI_Comm_spawn.  It works when I
launch with mpiexec but not if I run directly.

1) Is this a bug in MPICH?
2) What is the proper way for the program to detect how the program
was launched?  I would like to provide a helpful warning message...

Thanks!

Jeff

jrhammon-mac01:comm_spawn jrhammon$ ./parent
I am 0 of 1 for the parent program.
[mpiexec at jrhammon-mac01.local] match_arg
(../../../../src/pm/hydra/utils/args/args.c:159): unrecognized
argument pmi_args
[mpiexec at jrhammon-mac01.local] HYDU_parse_array
(../../../../src/pm/hydra/utils/args/args.c:174): argument matching
returned error
[mpiexec at jrhammon-mac01.local] parse_args
(../../../../src/pm/hydra/ui/mpich/utils.c:1596): error parsing input
array
[mpiexec at jrhammon-mac01.local] HYD_uii_mpx_get_parameters
(../../../../src/pm/hydra/ui/mpich/utils.c:1648): unable to parse user
arguments
[mpiexec at jrhammon-mac01.local] main
(../../../../src/pm/hydra/ui/mpich/mpiexec.c:153): error parsing
parameters
^C

jrhammon-mac01:comm_spawn jrhammon$ mpiexec -n 1 ./parent
I am 0 of 1 for the parent program.
I am 0 of 1 for the child program.

==> parent.c <==
#include <stdio.h>
#include <mpi.h>

int main(int argc, char * argv[])
{
    MPI_Init(&argc,&argv);

    int size, rank;
    MPI_Comm_size(MPI_COMM_WORLD, &size);
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);

    printf("I am %d of %d for the parent program.\n", rank, size);

    MPI_Comm intercomm;
    int errors[size];
    MPI_Comm_spawn( (char*)"./child", MPI_ARGV_NULL, 1, MPI_INFO_NULL,
0 /* root */, MPI_COMM_WORLD, &intercomm, errors);

    MPI_Finalize();
    return 0;
}

==> child.c <==
#include <stdio.h>
#include <mpi.h>

int main(int argc, char * argv[])
{
    MPI_Init(&argc,&argv);

    int size, rank;
    MPI_Comm_size(MPI_COMM_WORLD, &size);
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);

    printf("I am %d of %d for the child program.\n", rank, size);

    MPI_Finalize();
    return 0;
}

==> Makefile <==
CC      = mpicc
CFLAGS  = -g -O2 -Wall -std=c99

LD      = $(CC)
LDFLAGS = $(COPT)

LIBS =

TESTS= parent child

all: $(TESTS)

%: %.o
	$(CC) $(CFLAGS) $< $(LIBS) -o $@

clean:
	-rm -f *.o
	-rm -f $(TESTS)

-- 
Jeff Hammond
jeff.science at gmail.com
http://jeffhammond.github.io/