1MPI_Cart_sub(3) LAM/MPI MPI_Cart_sub(3)
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6 MPI_Cart_sub - Partitions a communicator into subgroups which form
7 lower-dimensional cartesian subgrids
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10 #include <mpi.h>
11 int MPI_Cart_sub(MPI_Comm comm, int *remdims, MPI_Comm *pnewcomm)
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14 comm - communicator with cartesian structure (handle)
15 remdims
16 - the i th entry of remdims specifies whether the i th dimension
17 is kept in the subgrid (true) or is dropped (false) (logical
18 vector)
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22 pnewcomm
23 - communicator containing the subgrid that includes the calling
24 process (handle)
25
28 All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have
29 an additional argument ierr at the end of the argument list. ierr is
30 an integer and has the same meaning as the return value of the routine
31 in C. In Fortran, MPI routines are subroutines, and are invoked with
32 the call statement.
33 All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in
35 Fortran.
36
39 If an error occurs in an MPI function, the current MPI error handler is
40 called to handle it. By default, this error handler aborts the MPI
41 job. The error handler may be changed with MPI_Errhandler_set ; the
42 predefined error handler MPI_ERRORS_RETURN may be used to cause error
43 values to be returned (in C and Fortran; this error handler is less
44 useful in with the C++ MPI bindings. The predefined error handler
45 MPI::ERRORS_THROW_EXCEPTIONS should be used in C++ if the error value
46 needs to be recovered). Note that MPI does not guarantee that an MPI
47 program can continue past an error.
48 All MPI routines (except MPI_Wtime and MPI_Wtick ) return an error
50 value; C routines as the value of the function and Fortran routines in
51 the last argument. The C++ bindings for MPI do not return error val‐
52 ues; instead, error values are communicated by throwing exceptions of
53 type MPI::Exception (but not by default). Exceptions are only thrown
54 if the error value is not MPI::SUCCESS .
55 Note that if the MPI::ERRORS_RETURN handler is set in C++, while MPI
58 functions will return upon an error, there will be no way to recover
59 what the actual error value was.
60 MPI_SUCCESS
61 - No error; MPI routine completed successfully.
62 MPI_ERR_TOPOLOGY
63 - Invalid topology. Either there is no topology associated with
64 this communicator, or it is not the correct type (e.g., MPI_CART
65 when expecting MPI_GRAPH ).
66 MPI_ERR_COMM
67 - Invalid communicator. A common error is to use a null commu‐
68 nicator in a call (not even allowed in MPI_Comm_rank ).
69 MPI_ERR_ARG
70 - Invalid argument. Some argument is invalid and is not identi‐
71 fied by a specific error class. This is typically a NULL
72 pointer or other such error.
73
76 For more information, please see the official MPI Forum web site, which
77 contains the text of both the MPI-1 and MPI-2 standards. These docu‐
78 ments contain detailed information about each MPI function (most of
79 which is not duplicated in these man pages).
80 http://www.mpi-forum.org/
82
86 The LAM Team would like the thank the MPICH Team for the handy program
87 to generate man pages ("doctext" from ftp://ftp.mcs.anl.gov/pub/sow‐
88 ing/sowing.tar.gz ), the initial formatting, and some initial text for
89 most of the MPI-1 man pages.
90
92 cartsub.c
93LAM/MPI 7.1.2 2/23/2006 MPI_Cart_sub(3)