#14654: implement flow polytopes
-------------------------------------+-------------------------------------
Reporter: ahmorales | Owner: graphcomponentowner
Type: enhancement | Status: needs_review
Priority: minor | Milestone: sage-wishlist
Component: graph theory | Resolution:
Keywords: flow polytopes, | Merged in:
kostant partition function, sage | Reviewers:
days 47.5 | Work issues:
Authors: ahmorales | Commit:
Report Upstream: N/A | a1fa21827894719e987b1ac3e41527e92df43f68
Branch: u/chapoton/14654 | Stopgaps:
Dependencies: |
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Comment (by ncohen):
Yo !
> Yes, but is there a way to just import the function as a method
`polytopes.flow_polytope` ?
There is, but it may be a bit awkard for in one version the function takes
a graph as an argument, and in the other `polytopes.flow_polytope(G)` it
needs to be provided explicitly... But maybe that is not a problem.
About importing the method:
{{{
sage: class A:
....: def hey(self):
....: print self
sage: A.hey(1)
...
TypeError: unbound method hey() must be called with A instance as first
argument (got Integer instance instead)
sage: A.hey.__func__(1)
1
}}}
But I am afraid that it does not preserve the docstring...
On the other hand it is possible to take a 'normal' function and make a
copy of it inside of a class. You have many functions like that at the end
of `graphs/graph.py`
> Well, for quiver guys like me, a source is a vertex with only outgoing
edges, and a sink with only incoming edge. Maybe you give them other
names. So there is no need to provide them as arguments. Of course one
needs to have as many sources as sinks for the flow polytope to make
sense. Every source gets an input of 1 and every sink an output of 1.
Oh I see `O_o`
Well, for graph guys like me we expect the sources to be explicitly given,
like in `GenericGraph.flow`.
HMmmm... Well, if you are positive that this is the standard that people
who call this method would expect, could you make it a bit clearer for the
graph guys ? Something like:
{{{
... and there is a unit of flow entering the sources (i.e. vertices of
indegree 0) and leaving the sinks (i.e. vertices of outdegree 0)
}}}
The point is that I would understand if you talk about "the sinks/sources
of a graph", but in the context of flow problem we expect the
sources/sinks to be specific vertices. Could you also add a sentence about
the necessity to have as many sinks as sources ?
Thaaaaaaanks and sorry for that ! Different people, different standards
`^^;`
Nathann
--
Ticket URL: <http://trac.sagemath.org/ticket/14654#comment:20>
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