---
name: "gcv"
section: "1"
platform: "linux"
package: "scotch"
version: "7.0.17-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/gcv"
---

# gcv(1)

graph file converter

## NAME

**gcv** - graph file converter

## SYNOPSIS

```
gcv [options] [igfile] [ogfile] [oxfile]
```

## DESCRIPTION

**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').**

## OPTIONS

- **-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.**

## EXAMPLE

**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
```

## SEE ALSO

**[gbase(1)](/gbase/1.md), [gtst(1)](/gtst/1.md), [gmap(1)](/gmap/1.md), [gord(1)](/gord/1.md), [gout(1)](/gout/1.md).**

**Scotch user's manual.**

## AUTHOR

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