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.TH MPI_Cart_sub 3 "1/6/1997" " " "MPI"
.SH NAME
MPI_Cart_sub \- Partitions a communicator into subgroups which form lower-dimensional cartesian subgrids
.SH SYNOPSIS
.nf
#include "mpi.h"
int MPI_Cart_sub ( comm, remain_dims, comm_new )
MPI_Comm comm;
int *remain_dims;
MPI_Comm *comm_new;
.fi
.SH INPUT PARAMETERS
.PD 0
.TP
.B comm
- communicator with cartesian structure (handle)
.PD 1
.PD 0
.TP
.B remain_dims
- the
.I i
th entry of remain_dims specifies whether the
.I i
th
dimension is kept in the subgrid (true) or is dropped (false) (logical
vector)
.PD 1
.SH OUTPUT PARAMETER
.PD 0
.TP
.B newcomm
- communicator containing the subgrid that includes the calling
process (handle)
.PD 1
.SH NOTES FOR FORTRAN
All MPI routines in Fortran (except for
.I MPI_WTIME
and
.I MPI_WTICK
) have
an additional argument
.I ierr
at the end of the argument list.
.I 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
.I call
statement.
All MPI objects (e.g.,
.I MPI_Datatype
,
.I MPI_Comm
) are of type
.I INTEGER
in Fortran.
.SH ERRORS
All MPI routines (except
.I MPI_Wtime
and
.I 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
.I MPI_Errhandler_set
; the predefined error handler
.I MPI_ERRORS_RETURN
may be used to cause error values to be returned.
Note that MPI does
.B not
guarentee that an MPI program can continue past
an error.
.PD 0
.TP
.B MPI_SUCCESS
- No error; MPI routine completed successfully.
.PD 1
.PD 0
.TP
.B MPI_ERR_TOPOLOGY
- Invalid topology. Either there is no topology
associated with this communicator, or it is not the correct type (e.g.,
.I MPI_CART
when expecting
.I MPI_GRAPH
).
.PD 1
.PD 0
.TP
.B MPI_ERR_COMM
- Invalid communicator. A common error is to use a null
communicator in a call (not even allowed in
.I MPI_Comm_rank
).
.PD 1
.PD 0
.TP
.B MPI_ERR_ARG
- Invalid argument. Some argument is invalid and is not
identified by a specific error class (e.g.,
.I MPI_ERR_RANK
).
.PD 1
.SH LOCATION
cart_sub.c
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