1MPI_Graph_create(3) LAM/MPI MPI_Graph_create(3)
2
6 MPI_Graph_create - Makes a new communicator to which topology informa‐
7 tion has been attached
8
10 #include <mpi.h>
11 int MPI_Graph_create(MPI_Comm comm, int nnodes, int *index,
12 int *edges, int reorder, MPI_Comm *newcomm)
13
15 comm - input communicator without topology (handle)
16 nnodes - number of nodes in graph (integer)
17 index - array of integers describing node degrees (see below)
18 edges - array of integers describing graph edges (see below)
19 reorder
20 - ranking may be reordered (true) or not (false) (logical)
21
24 newcomm
25 - communicator with graph topology added (handle)
26
29 LAM/MPI currently ignores the reorder flag.
30
33 All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have
34 an additional argument ierr at the end of the argument list. ierr is
35 an integer and has the same meaning as the return value of the routine
36 in C. In Fortran, MPI routines are subroutines, and are invoked with
37 the call statement.
38 All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in
40 Fortran.
41
44 If an error occurs in an MPI function, the current MPI error handler is
45 called to handle it. By default, this error handler aborts the MPI
46 job. The error handler may be changed with MPI_Errhandler_set ; the
47 predefined error handler MPI_ERRORS_RETURN may be used to cause error
48 values to be returned (in C and Fortran; this error handler is less
49 useful in with the C++ MPI bindings. The predefined error handler
50 MPI::ERRORS_THROW_EXCEPTIONS should be used in C++ if the error value
51 needs to be recovered). Note that MPI does not guarantee that an MPI
52 program can continue past an error.
53 All MPI routines (except MPI_Wtime and MPI_Wtick ) return an error
55 value; C routines as the value of the function and Fortran routines in
56 the last argument. The C++ bindings for MPI do not return error val‐
57 ues; instead, error values are communicated by throwing exceptions of
58 type MPI::Exception (but not by default). Exceptions are only thrown
59 if the error value is not MPI::SUCCESS .
60 Note that if the MPI::ERRORS_RETURN handler is set in C++, while MPI
63 functions will return upon an error, there will be no way to recover
64 what the actual error value was.
65 MPI_SUCCESS
66 - No error; MPI routine completed successfully.
67 MPI_ERR_COMM
68 - Invalid communicator. A common error is to use a null commu‐
69 nicator in a call (not even allowed in MPI_Comm_rank ).
70 MPI_ERR_ARG
71 - Invalid argument. Some argument is invalid and is not identi‐
72 fied by a specific error class. This is typically a NULL
73 pointer or other such error.
74
77 For more information, please see the official MPI Forum web site, which
78 contains the text of both the MPI-1 and MPI-2 standards. These docu‐
79 ments contain detailed information about each MPI function (most of
80 which is not duplicated in these man pages).
81 http://www.mpi-forum.org/
83
87 The LAM Team would like the thank the MPICH Team for the handy program
88 to generate man pages ("doctext" from ftp://ftp.mcs.anl.gov/pub/sow‐
89 ing/sowing.tar.gz ), the initial formatting, and some initial text for
90 most of the MPI-1 man pages.
91
93 graphcreate.c
94LAM/MPI 7.1.2 2/23/2006 MPI_Graph_create(3)