---
name: "ptscotch_dgmap"
section: "1"
platform: "linux"
package: "ptscotch"
version: "5.1.8a.dfsg-2"
release: "Debian 6.0 (Squeeze)"
platforms: ["linux"]
url: "https://new.carta.tech/ptscotch_dgmap"
---

# ptscotch\_dgmap(1)

compute static mappings and partitions in parallel

## NAME

**ptscotch\_dgmap, dgpart** - compute static mappings and partitions in parallel

## 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)](/amk_grf/1.md) program. See** **[gmap(1)](/gmap/1.md) 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.**

- **-m*strat***

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

- **-r*pnum***

  **Set root process for centralized files (default is 0).**

- **-V**

  **Display program version and copyright.**

- **-v*verb***

  **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)](/gmap/1.md) 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)](/dgscat/1.md) 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

**[ptscotch\_dgtst(1)](/ptscotch_dgtst/1.md), [ptscotch\_dgscat(1)](/ptscotch_dgscat/1.md), [scotch\_amk\_grf(1)](/scotch_amk_grf/1.md), [scotch\_acpl(1)](/scotch_acpl/1.md), [scotch\_gmap(1)](/scotch_gmap/1.md), [scotch\_gmtst(1)](/scotch_gmtst/1.md).**

**PT-Scotch user's manual.**

## AUTHOR

**Francois Pellegrini \<francois.pellegrini@labri.fr\>**