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)