[igraph] object 'membership' not found

[Glazko, Galina V]

Hello,

 

I am having a strange error; I did not see it before:

I have a large graph gs:

 

> summary(gs)

Vertices: 15088

Edges: 993338

Directed: FALSE

No graph attributes.

Vertex attributes: name.

No edge attributes.

 

is.connected(gs)

[1] TRUE

 

I am calculating modularity:

 

> mog.com<-fastgreedy.community(gs)

> memb <- community.to.membership(gs, mog.com$merges, steps=which.max(mog.com$modularity)-1 )

> modularity(gs, memb$membership)

[1] 0.4051626

 

and I want to get subgraph of  module N3:

 

$csize

[1] 3620 7290 3767   85   60   19    5    7    4    3    9    7    8    8    3    6    7    3    3    3    3    4    4    6    4    5    6    2    3    5    4    4    3    7

[35]    4    4    4    2    3    2    3    5    4    2    3    3    3    3    3    3    2    4    3    2    3    3    2    3    2    2    2    2    2    2    2    2    2    2

[69]    2    2    2    2    2    2    2    2    2

 

> i<-3

> s<-subgraph(gs,V(gs)[ membership == (i-1) ])

Error in eval(expr, envir, enclos) : object 'membership' not found

 

I do not understand the reason of this error message, what I am doing wrong?

 

thank you

best regards

 

Galina

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