Re: Query regarding graph layout in graph-tool

Hi Kapil,

Sorry for the late reply.

On 03/17/2011 10:50 AM, kapil gupta wrote:
> I want to know is it possible in graph-tool to nominate a node to be
> the centre of the graph and have the layout chose the distance of near
> by nodes to be directly proportional to the strength of the edge
> weight. The more two nodes correlate, the closer together they are.

I'm not sure if I understand precisely what you want, but you can
definitely "pin down" the position of a subset of the vertices, and let
the layout modify only the remaining ones. You can also set a "len" edge
property, which defines the preferred edge length for the layout. Take a
look at the full graphviz options at http://www.graphviz.org/content/attrs

To use these options with graph-tool, you should do something like:

    len = g.new_edge_property("double")
    len.a = 1.0 / weight.a                # your edge weight
    pin = g.new_vertex_property("bool")
    pin[root] = True   # root is the vertex which should be pinned down
    graph_draw(g, eprops={"len": len}, vprops={"pin": pin})

I hope this helps!

Cheers,
Tiago

--

-- 
Tiago de Paula Peixoto <tiago <at> skewed.de>

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