Search code examples
pygraphviz

Clusters are not showing

I am using the below code to generate a graph with two clusters with four nodes each For some reasons when I print the graph the clusters do not show up. What am I doing wrong?

import pygraphviz as pgv    

A=pgv.AGraph(bgcolor="#cccccc",layout='neato')
A.add_edge('R1','R2')
A.add_edge('R2','R3')
A.add_edge('R3','R4')
A.add_edge('R4','R5')
A.add_edge('R5','R6')
A.add_subgraph(['R1','R2','R3','R4'], 'pbd01')
A.add_subgraph(['R5','R6','R7','R8'], 'pbd02')


A.write('cluster.dot') 
A.draw('Topology.png', prog='neato')

enter image description here

Solution

  • I believe there are two problems:

    1. The 'neato' rendering engine does not support clustering
    2. By convention, rendering engines that do support clustering require that the subgraph name starts with 'cluster'

    The following code / image was produced with the 'dot' engine and correctly clusters the nodes:

    import pygraphviz as pgv    

A=pgv.AGraph(bgcolor="#cccccc",layout='dot')
A.add_edge('R1','R2')
A.add_edge('R2','R3')
A.add_edge('R3','R4')
A.add_edge('R4','R5')
A.add_edge('R5','R6')
A.add_subgraph(['R1','R2','R3','R4'], name='cluster_pbd01')
A.add_subgraph(['R5','R6','R7','R8'], name='cluster_pbd02')


A.write('cluster.dot') 
A.draw('Topology.png', prog='dot')

    Topology.png