---
name: "cluster"
section: "1"
platform: "linux"
package: "graphviz"
version: "16.1.0-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/cluster"
---

# cluster(1)

find clusters in a graph and augment the graph with this information.

## NAME

cluster - find clusters in a graph and augment the graph with this information.

## SYNOPSIS

**cluster** \[**-v?**\] \[ **-C***k* \] \[ **-c***k* \] \[ **-o** *outfile* \] \[  *files* \]

## DESCRIPTION

**cluster** takes as input a graph in DOT format, finds node clusters and augments  the graph with this information.  The clusters are specified by the "cluster" attribute attached to nodes; cluster values are non-negative integers. **cluster** attempts to maximize the modularity of the clustering. If the edge attribute "weight" is defined, this will be used in  computing the clustering.

## OPTIONS

The following options are supported:

- **-C***k*

  specifies a targeted number of clusters that should be generated. The specified number *k* is only a suggestion and may not be realisable.  If *k == 0*, the default, the number of clusters that approximately optimizes the modularity is returned.

- **-c***k*

  specifies clustering method. If *k == 0*, the default, modularity clustering will be used.  If *k == 1* modularity quality will be used.

- **-o***outfile*

  Specifies that output should go into the file *outfile*. By default, *stdout* is used.

- **-v**

  Verbose mode.

- **-?**

  Prints the usage and exits.

## EXAMPLES

Applying  **cluster** to the following graph,

```
   graph {
       1--2 [weight=10.]
       2--3 [weight=1]
       3--4 [weight=10.]
       4--5 [weight=10]
       5--6 [weight=10]
       3--6 [weight=0.1]
       4--6 [weight=10.]
      }
```

gives

```
   graph {
         node [cluster="-1"];
         1 [cluster=1];
         2 [cluster=1];
         3 [cluster=2];
         4 [cluster=2];
         5 [cluster=2];
         6 [cluster=2];
         1 -- 2 [weight="10."];
         2 -- 3 [weight=1];
         3 -- 4 [weight="10."];
         4 -- 5 [weight=10];
         5 -- 6 [weight=10];
         3 -- 6 [weight="0.1"];
         4 -- 6 [weight="10."];
   }
```

## AUTHOR

Yifan Hu \<yifanhu@yahoo.com\>

## SEE ALSO

[gvmap(1)](/gvmap/1.md)

Blondel, V.D., Guillaume, J.L., Lambiotte, R., Lefebvre, E.: Fast unfolding of communities in large networks. Journal of Statistical Mechanics: Theory and Experiment (2008), P10008.