Can you send us a small standalone test program that demonstrates the error? Rajeev On Nov 27, 2012, at 7:27 AM, Alejandro Allievi wrote:
Hi,
I'm setting up a grid topology and associated communicator using the function Setup_grid below. It works fine for process zero but throws:
Fatal error in PMPI_Comm_rank: Invalid communicator, error stack: PMPI_Comm_rank(109): MPI_Comm_rank(MPI_COMM_NULL, rank=000000000022FE4C) failed PMPI_Comm_rank(66).: Null communicator
Does MPICH2 for Win7 support topology functions???
Thanks for any help.
Alejandro
************CODE BELOW*************************** void Setup_grid(GRID_INFO_T* grid /* out */) { int old_rank; int dimensions[2]; int wrap_around[2]; int coordinates[2]; int free_coords[2];
/* Set up Global Grid Information */ MPI_Comm_size(MPI_COMM_WORLD, &(grid->p)); MPI_Comm_rank(MPI_COMM_WORLD, &old_rank);
printf("Process %d of %d inside Setup_Grid\n", old_rank, grid->p);
/* We assume p is a perfect square */ grid->q = (int) sqrt((double) grid->p); dimensions[0] = dimensions[1] = grid->q;
/* We want a circular shift in second dimension. */ /* Don't care about first */ wrap_around[0] = wrap_around[1] = 1; MPI_Cart_create(MPI_COMM_WORLD, 2, dimensions, wrap_around, 1, &(grid->comm));
MPI_Comm_rank(grid->comm, &(grid->my_rank)); MPI_Cart_coords(grid->comm, grid->my_rank, 2, coordinates); grid->my_row = coordinates[0]; grid->my_col = coordinates[1];
/* Set up row communicators */ free_coords[0] = 0; free_coords[1] = 1; MPI_Cart_sub(grid->comm, free_coords, &(grid->row_comm));
/* Set up column communicators */ free_coords[0] = 1; free_coords[1] = 0; MPI_Cart_sub(grid->comm, free_coords, &(grid->col_comm));
printf("Process %d leaving Setup_Grid\n", old_rank);
} /* Setup_grid */
-- Alejandro Allievi http://www.ace-net.ca/wiki/Alejandro_Allievi
"Tenez, mon ami, si vous y pensez bien, vous trouverez qu'en tout, notre véritable sentiment n'est pas celui dans lequel nous n'avons jamais vacillé; mais celui auquel nous sommes le plus habituellement revenus". Denis Diderot.
Este e-mail esta consignado sólo para el destinatario designado en el mismo y puede contener información confidencial y privilegiada. Su distribución o copiado está prohibido. Si Usted no fuera el destinatario designado, por favor notifíquenos de inmediato y destruya este e-mail en forma permanente así como todas las copias del mismo. Ce courriel peut renfermer des renseignements confidentiels et privilégiés et s'adresse au destinataire désigné seulement. La distribution ou la copie de ce courriel est interdit. Si vous n'êtes pas le destinataire désigné, veuillez nous en aviser immédiatement et détruire de façon permanente ce courriel ainsi que toute copie de celui-ci. This e-mail may contain confidential information, and is intended only for the named recipient and may be privileged. Distribution or copying of this email is prohibited. If you are not the named recipient, please notify us immediately and permanently destroy this email and all copies of it. _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss