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

AUTHOR

Francois Pellegrini <[email protected]>