Hello, I am processing the edge-betweenness of various networks using R igraph version 7.1. Those are spatial networks (each node has a (x,y) position) and I am using the "weight" option of the "edge.betweenness" function to take the spatial distances into account. This spatial distance is stored in an edge attribute called "dist".
Here is the command I use: edge.betweenness(graph=g, weights=E(g)$dist) However, for some of my networks, I get negative values, or even NaN. Here are two examples, under the graphml format: http://dx.doi.org/10.6084/m9.figshare.1540708 - scale=32.graphml - scale=41.graphml For the first one, the first values returned by "edge.betweenness" are: [1] 1904887544.08 1904887544.08 1896303182.39 1951787568.72 1203043060.76 [6] 1270869072.68 622780616.09 667964773.27 279064394.68 309184936.21 [11] 135403467.81 155266075.94 51600202.02 60120695.31 21113003.39 [16] 24783603.89 6275147.30 6937885.52 1347425.01 1002544.99 [21] 150574.42 -327097.77 -711849.38 -1430744.36 -246214.20 [26] -602827.15 -230344.97 -484630.12 -297768.08 -492364.06 For the second one, all the returned values are NaN. Note that all these weights are positive by definition. They even are non-zero since no two nodes hold the same position, by construction. I also checked this programmatically. Moreover, there are no multiple links, also by construction (and I checked with "has.multiple"). I was wondering if the negative or NaN values I get are due to me misusing the function, or if this is a bug in igraph. Thanks, Vincent Labatut
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