[mpich-discuss] Howto use MPI_Comm_merge together with MPI_Comm_spawn

[Umit]

*Hello Nick, *

*Thank you for your e-mail. *

*If  I call MPI_Intercomm_merge with all processes like this:
*
#define NUM_SPAWNS 4
double timer;
int i;
char str[100];

int main( int argc, char *argv[] )
{
    MPI_Comm parentcomm, intercomm;
    MPI_Comm comm;
    MPI_Init( &argc, &argv );
    MPI_Comm_get_parent( &parentcomm );
    int np = NUM_SPAWNS;

    if (parentcomm == MPI_COMM_NULL)
    {
        int errcodes[np];
        MPI_Comm_spawn( "/home/umit/Desktop/merge/./a.out", MPI_ARGV_NULL,
np, MPI_INFO_NULL, 0, MPI_COMM_WORLD, &intercomm, errcodes );
    }
    else
    {
        printf("I'm the spawned.\n");
    }
    *MPI_Intercomm_merge( intercomm, 1, &comm );*
    MPI_Finalize();
    return 0;
}

*
I am getting this time follgende error:*

umit at ubuntu:~/Desktop/merge$ mpirun -np 1 ./a.out
I'm the spawned.
*Fatal error in MPI_Intercomm_merge: Invalid communicator, error stack:*
MPI_Intercomm_merge(288): MPI_Intercomm_merge(comm=0x331ff4, high=1,
newintracomm=0xbf9d0720) failed
MPI_Intercomm_merge(93).: Invalid communicator
I'm the spawned.
Fatal error in MPI_Intercomm_merge: Invalid communicator, error stack:
MPI_Intercomm_merge(288): MPI_Intercomm_merge(comm=0xc71ff4, high=1,
newintracomm=0xbffec690) failed
MPI_Intercomm_merge(93).: Invalid communicator
rank 3 in job 56  ubuntu_38267   caused collective abort of all ranks
  exit status of rank 3: killed by signal 9
rank 0 in job 56  ubuntu_38267   caused collective abort of all ranks
  exit status of rank 0: killed by signal 9

Best Regards,




On 16 February 2012 15:56, Nick Radcliffe <nradclif at cray.com> wrote:

>  One problem is that the spawned child is not calling
> MPI_INTERCOMM_MERGE. The child needs to call the merge function in the
> 'else' part of your 'if (parentcomm == MPI_COMM_NULL)'.
>
> -Nick
>  ------------------------------
> *From:* mpich-discuss-bounces at mcs.anl.gov [
> mpich-discuss-bounces at mcs.anl.gov] on behalf of Umit [
> umitcanyilmaz at gmail.com]
> *Sent:* Thursday, February 16, 2012 7:06 AM
> *To:* mpich-discuss at mcs.anl.gov
> *Subject:* [mpich-discuss] Howto use MPI_Comm_merge together with
> MPI_Comm_spawn
>
>  Hello All,
>
> Can anyone tell me what is wrong with this simple code:
>
> #define NUM_SPAWNS 4
> double timer;
> int i;
> char str[100];
> int main( int argc, char *argv[] )
> {
>     MPI_Comm parentcomm, intercomm;
>     MPI_Comm comm, scomm;
>     MPI_Init( &argc, &argv );
>     MPI_Comm_get_parent( &parentcomm );
>     int np = NUM_SPAWNS;
>     int size;
>     MPI_Comm_size( MPI_COMM_WORLD , &size );
>     if (parentcomm == MPI_COMM_NULL)
>     {
>        scomm = MPI_COMM_WORLD;
>        int errcodes[np];
>        MPI_Comm_spawn( "/home/test/Desktop/merge/./a.out", MPI_ARGV_NULL,
> np, MPI_INFO_NULL, 0, MPI_COMM_WORLD, &intercomm, errcodes );
>        MPI_Intercomm_merge( intercomm, 1, &comm );
>     }
>     else
>     {
>         printf("I'm the spawned.\n");
>     }
>     MPI_Finalize();
>     return 0;
> }
>
> I called MPI_Intercomm_merge outside of if statement but I got the same
> error.
> Spawn is successfull. I have especially tested it. If I try to merge, i
> got the following error:
>
> test at ubuntu:~/Desktop/merge$ mpirun -np 1 ./a.out
> I'm the spawned.
> I'm the spawned.
> I'm the spawned.
> I'm the spawned.
> Fatal error in MPI_Intercomm_merge: Other MPI error, error stack:
> MPI_Intercomm_merge(288)..........: MPI_Intercomm_merge(comm=0x84000000,
> high=1, newintracomm=0xbf97ff40) failed
> MPI_Intercomm_merge(263)..........:
> MPIR_Get_contextid(639)...........:
> MPI_Allreduce(773)................: MPI_Allreduce(sbuf=MPI_IN_PLACE,
> rbuf=0xbf97fd18, count=64, MPI_INT, MPI_BAND, comm=0x84000002) failed
> MPIR_Allreduce(289)...............:
> MPIC_Sendrecv(161)................:
> MPIC_Wait(513)....................:
> MPIDI_CH3I_Progress(150)..........:
> MPID_nem_mpich2_blocking_recv(948):
> MPID_nem_tcp_connpoll(1720).......:
> state_commrdy_handler(1556).......:
> MPID_nem_tcp_recv_handler(1446)...: socket closed
> rank 0 in job 21  ubuntu_38267   caused collective abort of all ranks
>   exit status of rank 0: killed by signal 9
>
>
> Thanks In Advance,
>
>
>
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