MPI_Cart_sub
Partitions a communicator into subgroups which form lower-dimensional cartesian subgrids
Synopsis
#include "mpi.h"
int MPI_Cart_sub ( MPI_Comm comm, int *remain_dims, MPI_Comm *comm_new )
Input Parameters
| comm | communicator with cartesian structure (handle)
|
| remain_dims | the ith entry of remain_dims specifies whether the ith
dimension is kept in the subgrid (true) or is dropped (false) (logical
vector)
|
Output Parameter
- newcomm
- communicator containing the subgrid that includes the calling
process (handle)
Notes for Fortran
All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK) have
an additional argument ierr at the end of the argument list. ierr
is an integer and has the same meaning as the return value of the routine
in C. In Fortran, MPI routines are subroutines, and are invoked with the
call statement.
All MPI objects (e.g., MPI_Datatype, MPI_Comm) are of type INTEGER
in Fortran.
Errors
All MPI routines (except MPI_Wtime and MPI_Wtick) return an error value;
C routines as the value of the function and Fortran routines in the last
argument. Before the value is returned, the current MPI error handler is
called. By default, this error handler aborts the MPI job. The error handler
may be changed with MPI_Errhandler_set; the predefined error handler
MPI_ERRORS_RETURN may be used to cause error values to be returned.
Note that MPI does not guarentee that an MPI program can continue past
an error.
- MPI_SUCCESS
- No error; MPI routine completed successfully.
- MPI_ERR_TOPOLOGY
- Invalid topology. Either there is no topology
associated with this communicator, or it is not the correct type (e.g.,
MPI_CART when expecting MPI_GRAPH).
- MPI_ERR_COMM
- Invalid communicator. A common error is to use a null
communicator in a call (not even allowed in MPI_Comm_rank).
- MPI_ERR_ARG
- Invalid argument. Some argument is invalid and is not
identified by a specific error class (e.g., MPI_ERR_RANK).
Location:cart_sub.c