Re: [igraph] renumbering input graph

[Gábor Csárdi]

On Mon, Oct 27, 2008 at 4:04 PM, hazel vincent <address@hidden> wrote:
> 1.  I would like to renumber the nodes in my dataset before proceesing
> it using igraph since it is actually a subset of the entire data. Some
> functions tend to renumber vertices when a subset of the graph is
> chosen. Can this kind of renumbering be done on the graph that we
> supply, if it is a subset of the actual graph ?

To be honest I'm not completely sure what you want to do. In fact
vertices are always renumbered if a subgraph is created, simply
because the vertex ids are always between 0 and the number of vertices
minus one.

If you want to renumber vertices "by hand", you can call
igraph_permute_vertices (permute.vertices in R).

> 2. Besides the normal DFS method to figure out all the paths between 2
> nodes, is there any other efficient way to find all paths between 2
> nodes using igraph ?

Hmmm, igraph uses a breadth first search as far as I know, and I am
personally not aware of any other faster algorithms for this. If the
weighted case will ever be implemented that will use Dijkstra's
algorithm I guess.

Best,
Gabor

> Thanks,
> HD.
>
>
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-- 
Gabor Csardi <address@hidden>     UNIL DGM