#13698: Access to graph routines of the GLPK
------------------------------------------------------------------------+---
Reporter: christiankuper |
Owner: jason, jkantor
Type: enhancement |
Status: needs_review
Priority: major |
Milestone: sage-5.7
Component: numerical |
Resolution:
Keywords: out-of-kilter, minflow, maxflow, critical path, GLPK |
Work issues:
Report Upstream: N/A |
Reviewers:
Authors: Christian Kuper |
Merged in:
Dependencies: |
Stopgaps:
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Comment (by ncohen):
Two quick things :
* Why do you keep a pointer toward Sage's graph ``self.sage_graph`` ?
There are several problem with this design : the graph may be modified by
the user, while you keep a pointer toward a graph that gets modified.
Secondly, as it seems you only need it for two methods, you might as well
give the graph as a parameter to those two methods, and get rid of the
parameter.
* Don't do this :
{{{
sage: from sage.numerical.backends.glpk_graph_backend \
import GLPKGraphBackend
}}}
If you *need* to split lines, do it this way :
{{{
sage: from sage.numerical.backends.glpk_graph_backend \
... import GLPKGraphBackend
}}}
But you really shouldn't split lines so often. It' meant to make code
easier to read (a least I believe it is), but sometimes it really doesn't
help. As they appear really often, I think that you should let this line
stay even if it is very long. Besides, you very often don't need to add a
terinal `\`. For instance, this :
{{{
830 return (u, v, {"low":(<c_a_data
*>a.data).low, \
831 "cap":(<c_a_data
*>a.data).cap, \
832 "cost":(<c_a_data
*>a.data).cost, \
833 "x":(<c_a_data
*>a.data).x})
}}}
Can be replaced by
{{{
830 return (u, v, {"low":(<c_a_data
*>a.data).low,
831 "cap":(<c_a_data
*>a.data).cap,
832 "cost":(<c_a_data
*>a.data).cost,
833 "x":(<c_a_data
*>a.data).x})
}}}
It works, because Python knows the line is not finished : some
parenthesis are still open at this step, and it's waiting for `}` and `)`.
Nathann
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13698#comment:20>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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