1MPI_Cart_get(3) LAM/MPI MPI_Cart_get(3)
2
6 MPI_Cart_get - Retrieves Cartesian topology information associated
7 with a communicator
8
10 #include <mpi.h>
11 int MPI_Cart_get(MPI_Comm comm, int maxndims, int *dims,
12 int *periods, int *coords)
13
15 comm - communicator with cartesian structure (handle)
16 maxndims
17 - length of vectors dims , periods , and coords in the calling
18 program (integer)
19
22 dims - number of processes for each cartesian dimension (array of
23 integer)
24 periods
25 - periodicity (true/false) for each cartesian dimension (array
26 of logical)
27 coords - coordinates of calling process in cartesian structure (array
28 of integer)
29
32 All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have
33 an additional argument ierr at the end of the argument list. ierr is
34 an integer and has the same meaning as the return value of the routine
35 in C. In Fortran, MPI routines are subroutines, and are invoked with
36 the call statement.
37 All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in
39 Fortran.
40
43 If an error occurs in an MPI function, the current MPI error handler is
44 called to handle it. By default, this error handler aborts the MPI
45 job. The error handler may be changed with MPI_Errhandler_set ; the
46 predefined error handler MPI_ERRORS_RETURN may be used to cause error
47 values to be returned (in C and Fortran; this error handler is less
48 useful in with the C++ MPI bindings. The predefined error handler
49 MPI::ERRORS_THROW_EXCEPTIONS should be used in C++ if the error value
50 needs to be recovered). Note that MPI does not guarantee that an MPI
51 program can continue past an error.
52 All MPI routines (except MPI_Wtime and MPI_Wtick ) return an error
54 value; C routines as the value of the function and Fortran routines in
55 the last argument. The C++ bindings for MPI do not return error val‐
56 ues; instead, error values are communicated by throwing exceptions of
57 type MPI::Exception (but not by default). Exceptions are only thrown
58 if the error value is not MPI::SUCCESS .
59 Note that if the MPI::ERRORS_RETURN handler is set in C++, while MPI
62 functions will return upon an error, there will be no way to recover
63 what the actual error value was.
64 MPI_SUCCESS
65 - No error; MPI routine completed successfully.
66 MPI_ERR_TOPOLOGY
67 - Invalid topology. Either there is no topology associated with
68 this communicator, or it is not the correct type (e.g., MPI_CART
69 when expecting MPI_GRAPH ).
70 MPI_ERR_COMM
71 - Invalid communicator. A common error is to use a null commu‐
72 nicator in a call (not even allowed in MPI_Comm_rank ).
73 MPI_ERR_ARG
74 - Invalid argument. Some argument is invalid and is not identi‐
75 fied by a specific error class. This is typically a NULL
76 pointer or other such error.
77
80 For more information, please see the official MPI Forum web site, which
81 contains the text of both the MPI-1 and MPI-2 standards. These docu‐
82 ments contain detailed information about each MPI function (most of
83 which is not duplicated in these man pages).
84 http://www.mpi-forum.org/
86
90 The LAM Team would like the thank the MPICH Team for the handy program
91 to generate man pages ("doctext" from ftp://ftp.mcs.anl.gov/pub/sow‐
92 ing/sowing.tar.gz ), the initial formatting, and some initial text for
93 most of the MPI-1 man pages.
94
96 cartget.c
97LAM/MPI 7.1.2 2/23/2006 MPI_Cart_get(3)