[BioC] Rgraphviz - neato layout - edge weights have no effect

[Franz Quehenberger]

Dear all,

neato makes layouts according to a physical model in which the length of 
the edges is determined by springs. The weight of the edge is the 
strength of the spring. However, I was not able to find any influence of 
edge weight on the layout. In the 
http://www.graphviz.org/Documentation/neatoguide.pdf the attribute "len" 
is another parameter of the neato layout.

set.seed(31)
V=letters[1:5]
g2=randomEGraph(V,0.5)
plot(g2,"neato",main="All weights 1","All weights are 1.")

# change and edge weight
edgeData(g2, from = "d", to = "e", attr = "weight") <- 20
plot(g2,"neato",main="Nothing changed!")

#try out length attribute change
edgeDataDefaults(g2,"len")=1
edgeData(g2, from = "d", to = "e", attr = "len") <- 5
plot(g2,"neato",main="Nothing changed again!")


Has anyone an idea how to achieve a change in the graph layout ?

Best

Franz Quehenberger
-- 
Institute for Medical Informatics, Statistics and Documentation
Graz, Austria