[PPL-devel] [GIT] ppl/ppl(pip): Added a standalone PIP solver demo program.

François Galea francois.galea at uvsq.fr
Mon Nov 2 17:34:04 CET 2009


Sven Verdoolaege a écrit :
> On Fri, Oct 30, 2009 at 01:31:14PM +0100, Francois Galea wrote:
>> Thanks, I will have a look at these commits once I have implemented the  
>> support for bignums in the PPL solver.
> 
> Do you mean "big parameter"?

Indeed, this is what I meant.

> There's nothing really interesting to see in those commits.
> I just mentioned them to show I'm not hallucinating.
> In any case, in piplib, I just implemented the tricks
> described in the manual.  You should probably look at that
> before you start implementing.  Note that the manual proposes
> two different tricks to handle negative unknowns and 
> negative parameters.  I have no idea why.
> I mean, it's clear why you shouldn't use the other trick
> in the main tableau, but it's not clear why you shouldn't
> use a big parameter in the context tableau.
> But you are problaby not using the dual simplex + Gomory cuts
> technique in the context, so you shouldn't have a problem
> with negative parameters.

I will have a further look at all of this soon. Meanwhile, I still have 
fixes to do on the solver core.

Thank you for all your advice.

Best,

François.



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