Subgraph Drawing

Oscar Benjamin oscar.j.benjamin at gmail.com
Mon Jan 14 00:26:31 CET 2013


On 13 January 2013 20:05,  <subhabangalore at gmail.com> wrote:
> Dear Group,
>
> I have two questions, if I take a subseries of the matrix as in eigenvalue here,
> provided I have one graph of the full form in G, how may I show it, as if I do the nx.draw(G) it takes only the original graph.

I'm sorry, but I really don't understand what you mean. When you say
"subseries" do you mean "subgraph"? Or do you mean a subset of the
eigenvalues?

It would be good if you could give a simple example of what you mean
using code and showing the expected/desired output.

>
>>>> import numpy
>>>> import networkx as nx
>>>> import matplotlib.pyplot as plt
>>>> G=nx.Graph()
>>>> G.add_edges_from([(1,2),(1,3),(1,3),(1,4),(1,5),(1,6),(1,7),(1,8)])
>>>> L =nx.laplacian(G)
>>>> print L
> [[ 7. -1. -1. -1. -1. -1. -1. -1.]
>  [-1.  1.  0.  0.  0.  0.  0.  0.]
>  [-1.  0.  1.  0.  0.  0.  0.  0.]
>  [-1.  0.  0.  1.  0.  0.  0.  0.]
>  [-1.  0.  0.  0.  1.  0.  0.  0.]
>  [-1.  0.  0.  0.  0.  1.  0.  0.]
>  [-1.  0.  0.  0.  0.  0.  1.  0.]
>  [-1.  0.  0.  0.  0.  0.  0.  1.]]
>>>> print numpy.linalg.eigvals(L)
> [  8.00000000e+00   2.22044605e-16   1.00000000e+00   1.00000000e+00
>    1.00000000e+00   1.00000000e+00   1.00000000e+00   1.00000000e+00]
>
> for more than 1000 nodes it is coming too slow on Windows 7 machine with 3GB RAM.

What is too slow?


Oscar



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