NAME
ptscotch_dgmap, dgpart - compute static mappings and partitions in
parallel
SYNOPSIS
ptscotch_dgmap [options] [gfile] [tfile] [mfile] [lfile]
dgpart [options] [nparts] [gfile] [mfile] [lfile]
DESCRIPTION
The ptscotch_dgmap program computes, in a parallel way, a static
mapping of a source graph onto a target graph.
The dgpart program is a shortcut of ptscotch_dgmap for computing
partitions of a source graph.
Source graph file gfile is either a centralized graph file, or a set of
files representing fragments of a distributed graph. For
ptscotch_dgmap, the target architecture file tfile describes either
algorithmically-coded topologies such as meshes and hypercubes, or
decomposition-defined architectures created by means of the amk_grf(1)
program. See gmap(1) for a description of target architectures. The
resulting mapping is stored in file mfile. Eventual logging information
(such as the one produced by option -v) is sent to file lfile. When
file names are not specified, data is read from standard input and
written to standard output. Standard streams can also be explicitely
represented by a dash ’-’.
When the proper libraries have been included at compile time,
ptscotch_dgmap and dgpart can directly handle compressed graphs, both
as input and output. A stream is treated as compressed whenever its
name is postfixed with a compressed file extension, such as in
supported are the bzip2 format (’.bz2’), the gzip format (’.gz’), and
the lzma format (’.lzma’, on input only).
ptscotch_dgmap and dgpart base on implementations of the MPI interface
to spread work across the processing elements. They are therefore not
likely to be run directly, but instead through some launcher command
such as mpirun.
OPTIONS
-h Display some help.
-mstrat
Use parallel mapping strategy strat (see PT-Scotch user’s manual
for more information).
-rpnum Set root process for centralized files (default is 0).
-V Display program version and copyright.
-vverb Set verbose mode to verb. It is a set of one of more characters
which can be:
m mapping information.
s strategy information.
t timing information.
NOTE
At the time being (version 5.1.0), ptscotch_dgmap cannot compute full
static mappings as gmap(1) does, but only partitions (that is, mappings
onto unweighted or weighted complete graphs). Target architectures
other than the ’cmplt’ and ’wcmplt’ ones will lead to an error message.
EXAMPLES
Run dgpart on 5 processing elements to compute a partition into 7 parts
of graph brol.grf and save the resulting ordering to file brol.map.
$ mpirun -np 5 dgpart 7 brol.grf brol.map
Run dgpart on 5 processing elements to partition into 7 parts the
distributed graph stored on graph fragment files brol5-0.dgr to
brol5-4.dgr, and save the resulting mapping to file brol.map (see
dgscat(1) for an explanation of the ’%p’ and ’%r’ sequences in names of
distributed graph fragments).
$ mpirun -np 5 dgpart 7 brol%p-%r.dgr brol.map
SEE ALSO
ptscotch_dgtst(1), ptscotch_dgscat(1), scotch_amk_grf(1),
scotch_acpl(1), scotch_gmap(1), scotch_gmtst(1).
PT-Scotch user’s manual.
AUTHOR
Francois Pellegrini <francois.pellegrini@labri.fr>
September 08, 2008 ptscotch_dgmap(1)