xenial (1) scotch_gmap-int64.1.gz

Provided by: scotch_5.1.12b.dfsg-2build4_amd64 bug

NAME

       gmap, gpart - compute static mappings and partitions sequentially

SYNOPSIS

       gmap [options] [gfile] [tfile] [mfile] [lfile]

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

DESCRIPTION

       The gmap program computes, in a sequential way, a static mapping of a source graph onto a target graph.

       The  gpart program is a simplified interface to gmap, 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, gmap only accepts
       variable-sized target architectures.

       Source graph file gfile can only be a centralized graph file. For  gmap,  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. 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, gmap and gpart 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).

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.

              It is exclusive with the -m option.

       -h     Display some help.

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

       -q     (for gpart)

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

       -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.

TARGET ARCHITECTURES

       Target  architectures  represent  graphs  onto  which  source graphs are mapped. In order to speed-up the
       obtainment of target architecture  topological  properties  during  the  computation  of  mappings,  some
       classical  topologies are algorithmically coded into the mapper itself. These topologies are consequently
       simply defined by their code name, followed by their dimensional parameters:

       cmplt dim
              unweighted complete graph of size dim.

       cmpltw dim w0 w1 ... wdim-1
              weighted complete graph of size size and of respective loads w0, w1, ..., wdim-1.

       hcub dim
              hypercube of dimension dim.

       leaf hgt n0 w0 ... nhgt-1 whgt-1
              tree-leaf graph of height hgt with (n0 times n1 times ...  nhgt-1)  vertices,  with  inter-cluster
              link weights of w0, w1, ... whgt-1.

       mesh2D dimX dimY
              2D mesh of dimX times dimY nodes.

       mesh3D dimX dimY dimZ
              23 mesh of dimX times dimY times dimZ nodes.

       torus2D dimX dimY
              2D torus of dimX times dimY nodes.

       torus3D dimX dimY dimZ
              3D torus of dimX times dimY times dimZ nodes.

       Other  target  topologies  can  be  created  from  their source graph description by using the amk_grf(1)
       command. In this case, the target description will begin with the code name deco.

MAPPINGS

       Mappings are represented by as many lines as there are vertices in the source graph. Each of these  lines
       is  made of two figures: the number of the vertex (or its label if source graph vertices are labeled) and
       the index of the target vertex to which it has been assigned. Target vertex indices range from 0  to  the
       number of vertices in the target architecture (that is, the number of parts) minus one.

       This  block  of  lines is always preceded by the number of such lines. In most cases, since full mappings
       are requested, the number of lines is equal to the number of vertices in the source graph.

EXAMPLES

       Run gpart to compute a partition into 7 parts of graph 'brol.grf' and save the resulting ordering to file
       'brol.map'.

           $ gpart 7 brol.grf brol.map

       Run  gmap  to compute a partition, into 3 parts of respective weights 1, 2 and 4, of graph 'brol.grf' and
       save the resulting mapping to file 'brol.map'. The dash '-' standard file name is used so that the target
       architecture  description  is  read  from the standard input, through the pipe, as provided by the 'echo'
       shell command.

           $ echo "cmpltw 3 1 2 4" | gmap brol.grf - brol.map

SEE ALSO

       amk_grf(1), acpl(1), gmtst(1), dgmap(1).

       Scotch user's manual.

AUTHOR

       Francois Pellegrini <francois.pellegrini@labri.fr>

                                               September 01, 2011                                        gmap(1)