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## Re: [igraph] to attach edge weights

 From: Gabor Csardi Subject: Re: [igraph] to attach edge weights Date: Thu, 29 Nov 2007 08:50:51 +0100 User-agent: Mutt/1.5.13 (2006-08-11)

```The easiest is to use the 'weighted' argument of graph.adjacency:

m<- rbind(c(1, 0.2, 0.6), c(0.2, 1, 0.8), c(0.6, 0.8, 1))
diag(m) <- 0
m[ m<0.5 ] <- 0

Although i just noticed that 'weighted' and 'upper' don't work
well together, so if you want to create an undirected graph
here is a workaround:

m<- rbind(c(1, 0.2, 0.6), c(0.2, 1, 0.8), c(0.6, 0.8, 1))
diag(m) <- 0
m[ m<0.5 ] <- 0
m[ lower.tri(m) ] <- 0

Gabor

On Thu, Nov 29, 2007 at 11:42:36AM +0900, MATSUDA, Noriyuki wrote:
> Hello:
>
>    I'd be happy if any one can tell me how to attach edge weights on
> the basis of a connectedness/similarity matrix.  Suppose I do the
> following for a 3 by 3 correlation matrix
>    m<- rbind(c(1, 0.2, 0.6), c(0.2, 1, 0.8), c(0.6, 0.8, 1))
>    m(diag)<-NA;
>    m[m(a)<0.5] <-0;  m[m(a)>=0.5] <-1  #There must be a better way
>    g<-graph.adjacency(m, mode="upper"] #upper includes diagonals
>    E(g)\$weight ???????
>
> --
> MATSUDA, Noriyuki　<in Kanji> 松 田 紀 之
>
>
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