Blame www/www3/MPI_Graph_create.html

Packit Service c5cf8c
Packit Service c5cf8c
<HTML>
Packit Service c5cf8c
<HEAD>
Packit Service c5cf8c
<META NAME="GENERATOR" CONTENT="DOCTEXT">
Packit Service c5cf8c
<TITLE>MPI_Graph_create</TITLE>
Packit Service c5cf8c
</HEAD>
Packit Service c5cf8c
<BODY BGCOLOR="FFFFFF">
Packit Service c5cf8c

MPI_Graph_create

Packit Service c5cf8c
Makes a new communicator to which topology information has been attached 
Packit Service c5cf8c

Synopsis

Packit Service c5cf8c
Packit Service c5cf8c
int MPI_Graph_create(MPI_Comm comm_old, int nnodes, const int indx[],
Packit Service c5cf8c
                     const int edges[], int reorder, MPI_Comm * comm_graph)
Packit Service c5cf8c
Packit Service c5cf8c

Input Parameters

Packit Service c5cf8c
Packit Service c5cf8c
comm_old
input communicator without topology (handle)
Packit Service c5cf8c
Packit Service c5cf8c
nnodes
number of nodes in graph (integer)
Packit Service c5cf8c
Packit Service c5cf8c
indx
array of integers describing node degrees (see below)
Packit Service c5cf8c
Packit Service c5cf8c
edges
array of integers describing graph edges (see below)
Packit Service c5cf8c
Packit Service c5cf8c
reorder
ranking may be reordered (true) or not (false) (logical)
Packit Service c5cf8c
Packit Service c5cf8c

Packit Service c5cf8c

Output Parameters

Packit Service c5cf8c
Packit Service c5cf8c
comm_graph
communicator with graph topology added (handle)
Packit Service c5cf8c
Packit Service c5cf8c

Packit Service c5cf8c

Notes

Packit Service c5cf8c
Each process must provide a description of the entire graph, not just the
Packit Service c5cf8c
neigbors of the calling process.
Packit Service c5cf8c

Packit Service c5cf8c

Algorithm

Packit Service c5cf8c
We ignore the <tt>reorder</tt> info currently.
Packit Service c5cf8c

Packit Service c5cf8c

Thread and Interrupt Safety

Packit Service c5cf8c

Packit Service c5cf8c
This routine is thread-safe.  This means that this routine may be
Packit Service c5cf8c
safely used by multiple threads without the need for any user-provided
Packit Service c5cf8c
thread locks.  However, the routine is not interrupt safe.  Typically,
Packit Service c5cf8c
this is due to the use of memory allocation routines such as <tt>malloc
Packit Service c5cf8c
</tt>or other non-MPICH runtime routines that are themselves not interrupt-safe.
Packit Service c5cf8c

Packit Service c5cf8c

Notes for Fortran

Packit Service c5cf8c
All MPI routines in Fortran (except for <tt>MPI_WTIME</tt> and <tt>MPI_WTICK</tt>) have
Packit Service c5cf8c
an additional argument <tt>ierr</tt> at the end of the argument list.  <tt>ierr
Packit Service c5cf8c
</tt>is an integer and has the same meaning as the return value of the routine
Packit Service c5cf8c
in C.  In Fortran, MPI routines are subroutines, and are invoked with the
Packit Service c5cf8c
<tt>call</tt> statement.
Packit Service c5cf8c

Packit Service c5cf8c
All MPI objects (e.g., <tt>MPI_Datatype</tt>, <tt>MPI_Comm</tt>) are of type <tt>INTEGER
Packit Service c5cf8c
</tt>in Fortran.
Packit Service c5cf8c

Packit Service c5cf8c

Errors

Packit Service c5cf8c

Packit Service c5cf8c
All MPI routines (except <tt>MPI_Wtime</tt> and <tt>MPI_Wtick</tt>) return an error value;
Packit Service c5cf8c
C routines as the value of the function and Fortran routines in the last
Packit Service c5cf8c
argument.  Before the value is returned, the current MPI error handler is
Packit Service c5cf8c
called.  By default, this error handler aborts the MPI job.  The error handler
Packit Service c5cf8c
may be changed with <tt>MPI_Comm_set_errhandler</tt> (for communicators),
Packit Service c5cf8c
<tt>MPI_File_set_errhandler</tt> (for files), and <tt>MPI_Win_set_errhandler</tt> (for
Packit Service c5cf8c
RMA windows).  The MPI-1 routine <tt>MPI_Errhandler_set</tt> may be used but
Packit Service c5cf8c
its use is deprecated.  The predefined error handler
Packit Service c5cf8c
<tt>MPI_ERRORS_RETURN</tt> may be used to cause error values to be returned.
Packit Service c5cf8c
Note that MPI does not guarentee that an MPI program can continue past
Packit Service c5cf8c
an error; however, MPI implementations will attempt to continue whenever
Packit Service c5cf8c
possible.
Packit Service c5cf8c

Packit Service c5cf8c
Packit Service c5cf8c
MPI_SUCCESS
No error; MPI routine completed successfully.
Packit Service c5cf8c
Packit Service c5cf8c
Packit Service c5cf8c
MPI_ERR_TOPOLOGY
Invalid topology. Either there is no topology
Packit Service c5cf8c
associated with this communicator, or it is not the correct type (e.g.,
Packit Service c5cf8c
<tt>MPI_CART</tt> when expecting <tt>MPI_GRAPH</tt>).
Packit Service c5cf8c
Packit Service c5cf8c
Packit Service c5cf8c
MPI_ERR_COMM
Invalid communicator. A common error is to use a null
Packit Service c5cf8c
communicator in a call (not even allowed in <tt>MPI_Comm_rank</tt>).
Packit Service c5cf8c
Packit Service c5cf8c
Packit Service c5cf8c
MPI_ERR_ARG
Invalid argument. Some argument is invalid and is not
Packit Service c5cf8c
identified by a specific error class (e.g., <tt>MPI_ERR_RANK</tt>).
Packit Service c5cf8c
Packit Service c5cf8c

Packit Service c5cf8c
</BODY></HTML>