#7734: edge_coloring ( and possibly vertex_coloring ) loop forever when GLPK is
not installed
----------------------------+-----------------------------------------------
Reporter: ncohen | Owner: rlm
Type: defect | Status: positive_review
Priority: major | Milestone: sage-4.3.1
Component: graph theory | Keywords:
Work_issues: | Author:
Upstream: N/A | Reviewer:
Merged: |
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Changes (by rlm):
* status: needs_review => positive_review
Comment:
1. There should always be an example of the bug you are fixing in the
patch, always always always. We need a mug shot, so the bug doesn't show
its face again :) I added this, as well as several other tests, which have
exposed other corner case bugs, such as:
{{{
sage: g = Graph(20)
sage: vertex_coloring(g, hex_colors=True)
{'#ff0000': 0}
}}}
I've fixed these.
2. It seems to take some time to add constraints to the problem, which is
pointless if no solver is installed. Can you add a patch that runs a
trivial test before setting up the problem, to see if it is installed?
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/7734#comment:2>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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