Hello !!!
> This is coming from the code around line 1000 of c_graph, which goes
> from vertex labels to ints and back. The IntegerMod case was not in
> mind when this code was written. The real problem is that when the
> Python int 0 gets passed to get_vertex, it does not add the entry to
> the translation dictionary. The idea being that it would be more
> efficient for the majority of graphs, which only use [0, 1, ..., n-1]
> as labels, going through dictionaries a bunch would be a waste.
> However, when the IntegerMod 0 gets passed in, it does not find an
> equal object in the dict, and since it is not one of {int, long,
> Integer}, it assigns a new int in the translation dictionary for it.
>
> So that's what's happening, what do people think about what we should
> do about this? Technically the input is a bit fuzzy, but this raises
> the question of how many other objects are there which will pass the
> test int(0) == IntegerMod(0, 20)... I am very reluctant to support
> adding all the labels to the dicts, unless someone can show that there
> really isn't any overhead there...
Hmmmm.. I would not want to see any loss of performance because of
such matters either, I think we quite agree on this point..
I understood from your explanation why Mod(1,n) is considered
different from 0, and it is to me the correct behaviour... But what
about this
g has 21 vertices
len(g.vertices) == 20 ?
Sorry if you answered already ! :-)
Nathann
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