#18765: Add Cython wrappers for GLPK's interface glpssx.h (exact rational 
simplex)
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       Reporter:  mkoeppe      |        Owner:
           Type:  enhancement  |       Status:  new
       Priority:  minor        |    Milestone:  sage-6.8
      Component:  numerical    |   Resolution:
       Keywords:  lp           |    Merged in:
        Authors:               |    Reviewers:
Report Upstream:  N/A          |  Work issues:
         Branch:               |       Commit:
   Dependencies:               |     Stopgaps:
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Comment (by mkoeppe):

 Replying to [comment:1 dimpase]:
 > I don't understand how using standard glp_ functions would not lead to
 loss of precision, rendering subsequent exact computations meaningless.
 Are you doing to watch for the numerical troubles in the double-float
 phase?

 One just uses double float to navigate to some basis that's hopefully
 close to an optimal one.
 Then move to the same basis in the exact problem, and start exact simplex
 from there. This is always correct, no matter what numerical troubles the
 double-float phase ran into.

 > Further, I don't think using non-public non-documented features is a
 good idea. Next version would break them, and we'd be stuck with
 maintaining a fork...
 > Perhaps we have to find a way first to make GLPK folks finally address
 the public need of making these things public?

 With this ticket I want to first find out it will be worth it,
 performance-wise, comparing to other options. If it is, we can look into
 asking the GLPK developers.

--
Ticket URL: <http://trac.sagemath.org/ticket/18765#comment:2>
Sage <http://www.sagemath.org>
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