Re: [igraph] Question about fastgreedy.community

[hz hanks]

Hi, Tamás Nepusz

Thank you so much for your reply!

I tried to use your second solution, but it still has an error as follows:

g =degree.sequence.game(deg,method="vl")

At gengraph_mr-connected.cpp:146 : Cannot make a connected graph from
the given degree sequence, Invalid value

Do you have any method to fix it?

Thank you again for attention on my affair!

Best,
Hanks


2012/5/4 Tamás Nepusz <address@hidden>:
>> I'm a starter in igraph and also in R. I met a problem when learn
>> about fastgreedy.community
>
> The problem lies not within fastgreedy.community but within the graph 
> generated by degree.sequence.game. The default generation method ("simple") 
> does not prevent degree.sequence.game from creating loop or multiple edges, 
> and if it does, fastgreedy.community will fail. You have two options here:
>
> 1) call simplify() on the generated graph to get rid of multiple and loop 
> edges. Of course this distorts the degree sequence a bit, i.e. you won't get 
> exactly the same degree sequence as the one you have specified in "deg"
>
> 2) use method="vl" instead of method="simple" when calling 
> degree.sequence.game. method="vl" uses the Viger-Latapy generation method, 
> which is guaranteed to produce simple graphs that are then accepted by 
> fastgreedy.community.
>
> --
> T.
>
>
>
>
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