Scotch Brand 5.1.10 - Manual (Page 126)

Description
The METIS PartGraphVKway function performs a mapping onto the complete
graph of the graph represented by arrays xadj, adjncy, vwgt and vsize, using
the default Scotch mapping strategy. The options array is not used. The
part
array has the same meaning as the parttab array of Scotch.
Since Scotch does not have methods for explicitely reducing the communi-
cation volume according to the metric of METIS PartGraphVKway, this routine
creates a temporary edge weight array such that each edge (u, v) receives a
weight equal to mboxvsize(u) + mboxvsize(v). Consequently, edges which
are incident to highly communicating vertices will be less likely to be cut.
However, the communication volume value returned by this routine is ex-
actly the one which would be returned by MeTiS with respect to the output
partition. Users interested in minimizing the exact communication volume
should consider using hypergraphs, implemented in Scotch as meshes (see
Section 7.2.3).
All of the three MeTiS stubs METIS PartGraphKway, METIS PartGraph
Recursive
and METIS PartGraphVKway call the same Scotch routine, which
uses the Scotch default mapping strategy proved to be efficient in most cases.
8 Installation
Version 5.1 of the Scotch software package is distributed as free/libre software
under the CeCILL-C free/libre software license [6], which is very similar to the
GNU LGPL license. Therefore, it is no longer distributed as a set of binaries, but
instead in the form of a source distribution, which can be downloaded from the
Scotch
web page at http://www.labri.fr/~pelegrin/scotch/ .
All Scotch users are welcome to send an e-mail to the author so that they
can be added to the Scotch mailing list, and be automatically informed of new
releases and publications.
The extraction process will create a scotch 5.1.10 directory, containing several
subdirectories and files. Please refer to the files called LICENSE EN.txt or LICENCE
FR.txt
, as well as file INSTALL EN.txt, to see under which conditions your distri-
bution of Scotch is licensed and how to install it.
8.1 Thread issues
To enable the use of POSIX threads in some routines, the SCOTCH PTHREAD flag
must be set. If your MPI implementation is not thread-safe, make sure this flag is
not defined at compile time.
8.2 File compression issues
To enable on-the-fly compression and decompression of various formats, the rel-
evant flags must be defined.
These flags are COMMON FILE COMPRESS BZ2 for
bzip2 (de)compression, COMMON FILE COMPRESS GZ for gzip (de)compression, and
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