**gcv **- graph file converter

**gcv** [*options*] [*igfile*] [*ogfile*] [*oxfile*]

The

**gcv** program converts Scotch graph files from and to other external
file formats.

File

*igfile* is converted into graph file

*ogfile*, with optional
geometry data being put in geometry file

*oxfile*, if it is available.

When file names are not specified, data is read from standard input and written
to standard output. Standard streams can also be explicitly represented by a
dash '-'.

When the proper libraries have been included at compile time,

**gcv** 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).

**-h**
- Display some help.

**-i**?*ifmt*
- Set format of input graph file, which can be:

**b?***num*
- Boeing-Harwell format. This is a matrix format. Only square
matrices are supported. Square matrices with unsymmetric pattern are
symmetrized. In case the file contains several matrices, the
*num*
parameter allow the user to provide the index of the matrix to convert,
starting from 0. When the *num* parameter is not set, it is assumed
to be 0.

**c**
- Chaco format. This is an adjacency graph format, also used
by MeTiS.

**m**
- Matrix Market format. This is a matrix format describing
individual edges. Matrix pattern is symmetrized, such that rectangular
matrices are eventually squared.

**s**
- Scotch graph format. This is an adjacency graph
format.

**-o**?*ofmt*
- Set format of output graph file, which can be:

**c**
- Chaco format.

**m**
- Matrix Market symmetric pattern format.

**s**
- Scotch format. This is the default.

**-V**
- Display program version and copyright.

Convert a Matrix Market graph into a Scotch graph. Matrix Market files do not
comprise geometry data, so no geometry file is needed on output:

$ gcv -im brol.mm brol.grf

**gbase**(1),

**gtst**(1),

**gmap**(1),

**gord**(1),

**gout**(1).

Scotch user's manual.

Francois Pellegrini <francois.pellegrini@labri.fr>