Hi Bob,
> Sorry I only come back to you only now. shortest.paths does not seem to
> indicate the vertices that have been traversed in the shortest paths - just a
> matrix of those shortest paths.
Yup, but you can use get.shortest.paths() to get _one_ shortest path per vertex
pair, or get.all.shortest.paths() to get _all_ possible shortest paths between
vertices. Of course the output of the latter function can be huge, especially
if the graph has a regular structure (like a lattice) and there are many
shortest paths between the same pair of vertices.
> Having looked at closeness(), is seems that closeness is currently done as:
> res <- .Call("R_igraph_closeness", graph, vids - 1, mode, weights, PACKAGE =
> "igraph")
>
> How do I learn more of what is being done by this function? Many thanks.
It goes down to the C core of igraph, where it eventually ends up in a function
named igraph_closeness:
http://igraph.sourceforge.net/doc/html/ch13s06.html#igraph_closeness
The source code is here:
https://github.com/igraph/igraph/blob/master/src/centrality.c#L2565
However, this function requires extensive knowledge of the C layer of igraph,
so I don't know how useful it will be to you in the end. It boils down to doing
a breadth first search on the graph and recording the distances in a vector.
--
T.
_______________________________________________
igraph-help mailing list
igraph-help@nongnu.org
https://lists.nongnu.org/mailman/listinfo/igraph-help
