Re: [igraph] Non-Backtracking Matrix

[Gábor Csárdi]

Hi!

It is hard to say why it is slow, if you don't show the code. Please consider uploading it to github or gist.github.com.

Setting an element in a dense matrix has O(1) time complexity, so that should not be slow at all.

Best,

Gabor

On Tue, Jan 28, 2014 at 9:20 AM, Pierre-Andre Maugis <address@hidden> wrote:

Hello,

I am trying to build the non-backtracking matrix of a network. It is the matrix whose entries are indexed by the edges of the graph. Entries are 0 if the said edges do not form a path of length two, and 1 if they do. More details can be found in arXiv:1306.5550, p3.

All the algorithms I could produce are very slow. Computing the entries is not a problem, however storing them properly in the matrix is, and takes a lot of time.

I would welcome any suggestion on the topic.

Best,

Pierre-André Maugis

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