2013/1/9 Sirius Fuenmayor <[email protected]>
> I get a 'Segmentation fault (core dumped)' error when I try to calculate
> the pseudo_diameter() of a GraphView object <class 'graph_tool.GraphView'>.
> I must convert the GraphView object to a Graph object <class
> 'graph_tool.Graph'> to perform this calculation? How do I make this
> conversion?
>
> My detailed problem is:
>
> I have a graph that is fragmented in several components and I want to
> calculate several measures on every component, so I must extract every
> component as a graph to be able to apply the different tools on it. To do
> this I use label_components() to create a vertex PropertyMap that label the
> components
>
> vprop_comps, size_comps = gt.label_components(g)
>
> from this Property Map (vprop_comps) I create one Boolean PropertyMap for
> every component, the Boolean Property Map for a component will have 1 for
> every vertex that belong to this component and 0 otherwise, finally I
> construct a GraphView object from the Boolean Property Map of a component,
> and then apply the different tools on this object. My code is:
>
> # for all components
> for i in range(size_comps.size):
> # create a boolean property map
> vprop_component_i = g.new_vertex_property("bool")
> # explore the property map that label the components 'vprop_comps'
> for j in range(vprop_comps.a.size):
> # if vprop_comps sugest that vertex j is in component i
> if (vprop_comps.a[j] == i):
> # put 'true' in the property of vertex j in the property
> map of component i
> vprop_component_i[g.vertex(j)] = True
> # With the boolean property map constructed for component i I can
> create a
> # GraphView object representing component i:
> c_i = gt.GraphView(g, vfilt=vprop_component_i)
> # and apply the different measures on it:
> clust_c_i = gt.global_clustering(c_i)[0]
> length_c_i = gt.pseudo_diameter(c_i)[0]
>
> Everything goes fine until I calculate the pseudo_diameter() of c_i, if I
> try to, I receive a 'Segmentation fault (core dumped)' error.
>
> Is there a more direct way to extract the components as graph objects?
>
I don't know about the segfault (I encountered the same problem with a test
graph), your approach uses too much code to select the components. I
suggest the following:
vprop_comps, size_comps = gt.label_components(g)
for i in range(len(size_comps)):
gv = gt.GraphView(g,vfilt=lambda x: vprop_comps[x]==i)
Hope it helps, at least in having a cleaner code.
Giuseppe
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