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
mbox
vsize
(
u
) +
mbox
vsize
(
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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