NAME

       dgmap, dgpart - compute static mappings and partitions in parallel

SYNOPSIS

       dgmap [options] [gfile] [tfile] [mfile] [lfile]

       dgpart [options] [nparts/pwght] [gfile] [mfile] [lfile]

DESCRIPTION

       The  dgmap  program computes, in a parallel way, a static mapping of a source graph onto a
       target graph.

       The dgpart program is a simplified interface to dgmap, which performs  graph  partitioning
       instead  of  static mapping. Consequently, the desired number of parts has to be provided,
       in lieu of the target architecture. When using  the  program  for  graph  clustering,  the
       number of parts turns into maximum cluster weight.

       The  -b  and  -c  options allow the user to set preferences on the behavior of the mapping
       strategy which is used by default. The -m option  allows  the  user  to  define  a  custom
       mapping strategy.

       The  -q option turns the programs into graph clustering programs. In this case, dgmap only
       accepts variable-sized target architectures.

       Source graph file gfile is either a centralized graph file, or a set of files representing
       fragments  of a distributed graph. For 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, 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
       'brol.grf.bz2' or '-.gz'. The compression formats which can be  supported  are  the  bzip2
       format ('.bz2'), the gzip format ('.gz'), and the lzma format ('.lzma', on input only).

       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

       -bval  Set  maximum  load  imbalance  ratio for graph partitioning or static mapping. When
              programs are used as  clustering  tools,  this  parameter  sets  the  maximum  load
              imbalance ratio for recursive bipartitions. Exclusive with the -m option.

       -copt  Choose default mapping strategy according to one or several options among:

              b      enforce load balance as much as possible.

              q      privilege quality over speed (default).

              s      privilege speed over quality.

              t      enforce safety.

              x      enforce scalability.

              It is exclusive with the -m option.

              -h     Display some help.

              -mstrat
                     Use  parallel  mapping  strategy strat (see PT-Scotch user's manual for more
                     information).

              -q     (for dgpart)

              -qpwght
                     (for dgmap) Use the programs as graph clustering  tools  instead  of  static
                     mapping  or  graph  partitioning tools. For dgpart, the number of parts will
                     become the maximum cluster weight. For dgmap, this number pwght  has  to  be
                     passed after the option.

              -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), 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

       dgtst(1), dgscat(1), amk_grf(1), acpl(1), gmap(1), gmtst(1).

       PT-Scotch user's manual.

AUTHOR

       Francois Pellegrini <francois.pellegrini@labri.fr>

                                        September 01, 2011                               dgmap(1)