Thanks, Moritz.
I found a solution which used strings instead of tuples:
for v in G.vertex_iterator():
v.rename(str(v)[12:])
Probably not as elegant as your solution, but it did the job!
-Alasdair
On Monday, 26 February 2018 06:22:32 UTC+11, moritz wrote:
>
>
>
> On Saturday, February 24, 2018 at 9:56:04 AM UTC+1, Alasdair wrote:
>>
>> Hello,
>>
>> I have defined a polyhedron by a collection of linear inequalities over
>> three variables, and it's all lovely: I can access the vertices, draw all
>> sorts of nice pictures, get all sorts of information. The one problem is
>> the vertex graph. If my polyhedron is P, say, then P.vertex_graph() gives
>> me a graph where each vertex is labelled something like "A vertex at
>> (0,1,0)". This seems somewhat redundant labelling, and ideally I'd like to
>> relabel the vertices to simply "(0,1,0)".
>>
>> I attempted to relabel the vertex graph with:
>>
>> dict ={i:j, for (i,j) in zip(P.vertices(),P.vertex_list())
>> G = P.vertex_graph()
>> G.relabel(dict)
>>
>>
>> However, that attempt produced the error:
>>
>> TypeError: unhashable type: 'list'
>>
>>
>> I'm not sure how to go about this relabelling... any idea? Thanks!
>>
> a 'list' cant be a vertex of a graph. It needs to be something hashable,
> like a 'tupe'. Try the code below.
>
> Cheers
> Moritz
>
> sage: P = polytopes.cube()
> sage: G = P.graph()
> sage: G.vertices()
> [A vertex at (-1, -1, -1),
> A vertex at (-1, -1, 1),
> A vertex at (-1, 1, -1),
> A vertex at (-1, 1, 1),
> A vertex at (1, -1, -1),
> A vertex at (1, -1, 1),
> A vertex at (1, 1, -1),
> A vertex at (1, 1, 1)]
> sage: dict ={i:tuple(j) for (i,j) in zip(P.vertices(),P.vertices_list())}
> sage: G.relabel(dict)
> sage: G.vertices()
> [(-1, -1, -1),
> (-1, -1, 1),
> (-1, 1, -1),
> (-1, 1, 1),
> (1, -1, -1),
> (1, -1, 1),
> (1, 1, -1),
> (1, 1, 1)]
> sage: dict
> {A vertex at (-1, -1, -1): (-1, -1, -1),
> A vertex at (-1, -1, 1): (-1, -1, 1),
> A vertex at (-1, 1, -1): (-1, 1, -1),
> A vertex at (-1, 1, 1): (-1, 1, 1),
> A vertex at (1, -1, -1): (1, -1, -1),
> A vertex at (1, -1, 1): (1, -1, 1),
> A vertex at (1, 1, -1): (1, 1, -1),
> A vertex at (1, 1, 1): (1, 1, 1)}
>
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