Re: [igraph] Shortest path with highest weights

[Ragia Ibrahim]

Brilliant .
lots of thanks

> Date: Sun, 4 Jan 2015 21:19:51 +0100
> From: address@hidden
> To: address@hidden
> Subject: Re: [igraph] Shortest path with highest weights
>
> > Dear group,
> > kindly I have a graph that got the following edges:
> > 6 -> 4 with prob 0.4
> > 4 -> 3 with prob 0.2
> >
> > 6 -> 7 with prob 0.1
> > 7 -> 3 with prob 0.01
> >
> > I want to get the shortest path between 6, 3 with the highest probability "prob"
> > this I wrote this:
> > max(E(G,path=get.shortest.paths(G,6,3)$vpath[[1]])$prob)
> >
> > this do not give me the vertices in between, how can I get them? and can
> > I multiply probabilities instead of adding ?
> get.shortest.paths, get.all.shortest.paths and related functions always look
> for the path that has the smallest total weight on the edges. If you have
> probabilities and you want to _maximize_ the _product_ of the probabilities,
> you need to employ a simple trick: replace each probability with its logarithm
> times -1 because additions with the log-probabilities work the same way as
> multiplications with the "original" probabilities (and you need the -1
> multiplier because you want to maximize the product and get.shortest.paths will
> try to minimize them).
>
> Best,
> T.
>
> _______________________________________________
> igraph-help mailing list
> address@hidden
> https://lists.nongnu.org/mailman/listinfo/igraph-help