I will give it a try, this sounds like a sensible suggestion, although - for the first suggestion - my network already has weights (the strength of a relationship). Need to find out how to create (how does one assign coordinates and create noise?) and assign (how does one 'place a node'?). Have some work with layouts to do. Many thanks. Bob
Kindly, Bob Pap On 29 August 2013 12:22, Tamás Nepusz <[email protected]> wrote: > > Maybe some has faced the following situation: vertices in a network > have an attribute (think of - for example - a sport they play frequently), > which has a role in how they are related (within-attribute edges are more > frequent and stronger than outside-attribute). Would it be possible to > layout the network in a way that graphically 'groups' the attributes (sport > teams) and then still shows the vertices and their edges in a sensible way? > You can probably use the weighted Fruchterman-Reingold layout in igraph. > Set up the edge weights such that edges within a group have significantly > larger weight than edges between groups, and then run the layout algorithm. > That should do the trick. In case the layout algorithm is not able to > figure out an appropriate layout on its own, you can "help" it by providing > it with a seed layout where the nodes in the different groups are already > separated to some extent. For instance, if you have k groups, then choose k > points along the circumference of a circle with a sufficiently large > radius, and place the nodes in group i around point i, adding some random > noise to avoid nodes ending up at exactly the same position. Then pass this > seed layout to the weighted Fruchterman-Reingold layout with appropriate > weights. > > All the best, > -- > T. > > > _______________________________________________ > igraph-help mailing list > [email protected] > https://lists.nongnu.org/mailman/listinfo/igraph-help >
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