Re: [igraph] Confusing results with get_shortest_paths

[Tamás Nepusz]

Hello,

Your code seems to be fine but I cannot reproduce the issue on my machine -- 
neither with Python 2.7 nor with Python 3.3.1. Can you send me a self-contained 
example that constructs the graph from scratch and reproduces the problem on 
your machine? Also, it would be helpful to know as many details about your 
platform as possible (i.e. operating system, whether this is a 32-bit or 64-bit 
machine, whether you have compiled igraph yourself or used an official 
pre-compiled package, and anything else that you may deem relevant).

The output from my igraph session is as follows:

>>> import igraph
>>> g=igraph.Graph([(0,1),(1,2),(2,3)], directed=False)
>>> from itertools import combinations
>>> for s,t in combinations(g.vs, 2):
...     g.get_shortest_paths(s,t)[0]
... 
[0, 1]
[0, 1, 2]
[0, 1, 2, 3]
[1, 2]
[1, 2, 3]
[2, 3]

All the best,
Tamas

On 16 Jul 2013, at 21:44, Frederik Elwert <address@hidden> wrote:

> Hello,
> 
> I am new to igraph, so I might be getting something wrong. I am using
> igraph 0.6.5 with python3.
> 
> I have a graph and want to calculate the shortest paths between all
> pairs of nodes:
> 
>>>> graph.is_directed()
>        False
>>>> graph.get_edgelist()
>        [(0, 1), (1, 2), (2, 3)]
>>>> for source, target in combinations(graph.vs, 2):
>        ...     graph.get_shortest_paths(source, target)[0]
>        [0, 1]
>        [0, 1, 2]
>        [0, 2, 3]
>        [1, 2]
>        [1, 0, 3]
>        [2, 3]
> 
> What bothers me: The paths [0, 2, 3] and [1, 0, 3] seem to be invalid.
> There should be no edge 0 -- 2 or 0 -- 3.
> 
> Any hints?
> 
> Regards,
> Frederik
> 
> 
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