#18929: Include igraph library
-------------------------------------+-------------------------------------
Reporter: borassi | Owner:
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-6.8
Component: packages: | Resolution:
optional | Merged in:
Keywords: igraph library | Reviewers: Nathann Cohen
Authors: Michele Borassi | Work issues:
Report Upstream: N/A | Commit:
Branch: | fc693a955362964e4c7bb73c75b74c65e7dbebef
u/borassi/include_igraph_library | Stopgaps:
Dependencies: |
-------------------------------------+-------------------------------------
Comment (by borassi):
Replying to [comment:30 dcoudert]:
> My first trial was with the source code from [1] and [2].
> One difficulty is that [2] gives `python-igraph...` and not
`python_igraph...`
This is exactly the reason why I made the `spkg-src` script (Sage cannot
install packages with dashes inside their names).
> Now I'm trying with [4] and it's working... but then it says that igraph
is not installed.
> So I'm running `./sage -i igraph` using the source code from [3] (should
work also with [1]).
>
> The point is that before installing igraph, I installed this patch and
performed the following test:
> {{{
> sage: G = graphs.[wiki:PetersenGraph]()
> sage: G.igraph_graph()
>
---------------------------------------------------------------------------
> ImportError Traceback (most recent call
last)
> <ipython-input-2-07a5568607db> in <module>()
> ----> 1 G.igraph_graph()
>
> /Users/dcoudert/sage/local/lib/python2.7/site-
packages/sage/graphs/generic_graph.pyc in igraph_graph(self, vertex_attrs,
edge_attrs)
> 1432 raise ImportError("The package igraph is not available.
To " +
> 1433 "install it, run Sage with option -i
" +
> -> 1434 "python_igraph.")
> 1435
> 1436 v_to_int = {v:i for i,v in enumerate(self.vertices())}
>
> ImportError: The package igraph is not available. To install it, run
Sage with option -i python_igraph.
> sage:
> }}}
> I don't know if the installation of `python_igraph` is expected to
install `igraph` as well or not. If not, then the error message should be
improved.
Hmmmmm, good question. I added igraph to the dependencies of
python_igraph, but maybe it is not sufficient (see comments 4-5)...
Nathann??
> Now that it is working, I did
> {{{
> sage: G = graphs.[wiki:PetersenGraph]()
> sage: H = G.igraph_graph()
> sage: H.<TAB>
> }}}
> and got access to the list of methods.
> It is surprizing to see that we have both graph algorithms and graph
generators (e.g. `Barabasi`, `Erdos_Renyi`, etc.), but I assume there is
nothing you can do to avoid that. Not a big deal.
> Also, some methods for digraphs (e.g., `all_st_mincuts`) are accessible
from undirected graphs and so an error is raised, but again I assume there
is nothing we can do about it.
> {{{
> sage: H.is_directed()
> False
> sage: H.all_st_mincuts(0,2)
>
---------------------------------------------------------------------------
> NotImplementedError Traceback (most recent call
last)
> <ipython-input-22-8251331c5c90> in <module>()
> ----> 1 H.all_st_mincuts(Integer(0),Integer(2))
>
> /Users/dcoudert/sage/local/lib/python2.7/site-
packages/python_igraph-0.7.0-py2.7-macosx-10.9-x86_64.egg/igraph/__init__.pyc
in all_st_mincuts(self, source, target, capacity)
> 390 graphs. Algorithmica 15, 351--372, 1996.
> 391 """
> --> 392 value, cuts, parts = GraphBase.all_st_mincuts(self,
source, target, capacity)
> 393 return [Cut(self, value, cut=cut, partition=part)
> 394 for cut, part in izip(cuts, parts)]
>
> NotImplementedError: Error at st-cuts.c:1320: S-t cuts can only be
listed in directed graphs, Unimplemented function call
> }}}
> Anyway, its working.
>
> I will now try to understand the point of disagreement between you and
Nathann.
>
> David.
--
Ticket URL: <http://trac.sagemath.org/ticket/18929#comment:31>
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