Re: [ojAlgo-user] Integer solver

[Francisco V. <fra...@gm...>]

Thanks Anders,
sorry, but I have a lot of work. I thought about this in summer work.
Cheers.


El miércoles, 27 de marzo de 2013, Anders Peterson escribió:

> Ok. Everything works now except semi-continuous variables in mps-files and
> some harder mip models (mps-files) that I downloaded from MIPLIB.
>
> MIPLIP classifies problem instances as "easy" if they can be solved within
> one hour using a commercial MIP solver, and also lists problems that are
> not yet solved by any solver. ojAlgo has, previously, solved at least one
> of these, but I do not know what the current state is.
>
> @ Francisco Verdejo : ojAlgo can now handle the model you sent me. The
> returned state is OPTIMAL, the solution satisfies all constraints and
> integer variables are at integer values.
>
> /Anders
>
>
> On 18 mar 2013, at 10:42, Anders Peterson <an...@op...> wrote:
>
> > I have worked some on solving this problem - here's un update on the
> general state of the optimization functionality in ojAlgo:
> >
> > junit tests for package...
> >
> > org.ojalgo.optimisation.quadratic: All tests pass
> >
> > org.ojalgo.optimisation.linear: All tests pass
> >
> > org.ojalgo.optimisation.integer: All tests pass, but the test
> corresponding to the problem reported in this thread is not proper.
> Validation and debug output indicates there is still some problem.
> >
> > org.ojalgo.optimisation.linear.mps: Tests related to semi continuous
> variables, and 2 other cases downloaded from netlib fail. Other tests are
> ok.
> >
> > org.ojalgo.optimisation.integer.mps: Several problems here! In many
> cases ojAlgo even has problems solving the relaxed LP problems.
> >
> >
> > To summarize:
> > 1) Semi continuos variables in mps files doesn't work
> > 2) The chain mps-file - IntegerSolver - LinearSolver seems to be
> problematic. Most likely there's more than one bug/problem. This
> chain/combination is just a good way to replicate the symptoms.
> >
> >
> > Please help buy supplying small manageable test cases that indicate
> various problems!
> >
> >
> > /Anders
> >
> >
> > On 26 feb 2013, at 14:30, Anders Peterson <an...@op...> wrote:
> >
> >> I suspect it's not trivial to grasp the inner workings of
> ExpressionsBasedModel, IntegerSolver and LinearSolver...
> >>
> >> Finding a smaller model that demonstrates the bug would be very helpful.
> >>
> >> If you do try to debug the code, please get the latest source directly
> from cvs.
> >>
> >> http://sourceforge.net/p/ojalgo/code/
> >>
> >> /Anders
> >>
> >>
> >> On 26 feb 2013, at 11:33, Francisco Verdejo <fra...@gm...>
> wrote:
> >>
> >>> Hi Anders,
> >>> I go to try to debug the problem and simplify the model but I need
> time.
> >>>
> >>> Thanks for your interest.
> >>> Fran.
> >>>
> >>>
> >>> 2013/2/26 Anders Peterson <an...@op...>
> >>> Can't see (yet) exactly what the problem is, but it seems to be
> related to extracting and copying solutions back and forth between the
> model and solver. The MIP solver is multithreaded, and that adds to the
> problem...
> >>>
> >>> Any one else have problems with the MIP solver? It is very likely the
> problem was introduced during December/January when I did a lot of work on
> to the MIP solver.
> >>>
> >>> I'm a little short on time at the moment. You have the source code.
> Please participate in debugging this.
> >>>
> >>> One thing that would help a lot is if this behavior can be reproduced
> in a smaller (as small as possible) model. Would be great if it was
> possible to simply print the entire simplex tableau and/or all related
> matrices...
> >>>
> >>> /Anders
> >>>
> >>>
> >>> On 25 feb 2013, at 11:55, Francisco Verdejo <fra...@gm...>
> wrote:
> >>>
> >>>> Hi,
> >>>> Sorry for waiting, I have prepared an example which I send.
> >>>> Seems that it skips the restrictions of variables for satisfy the
> restrictions of expression.
> >>>> I hope it helps you to solve the problem.
> >>>> Thanks.
> >>>> Fran.
> >>>>
> >>>>
> >>>> 2013/2/22 Anders Peterson <an...@op...>
> >>>> Send me a, self-contained and directly-runnable, test case. If you
> can reproduce the problem with a small(er) model then please do that.
> /Anders
> >>>>
> >>>> On 22 feb 2013, at 12:48, Francisco Verdejo <fra...@gm...>
> wrote:
> >>>>
> >>>>> The variables are binay and the X_111_19=-16
> >>>>> Also exits the folowing resOwn the Future-Intel&reg; Level Up Game
> Demo Contest 2013
> Rise to greatness in Intel's independent game demo contest.
> Compete for recognition, cash, and the chance to get your game
> on Steam. $5K grand prize plus 10 genre and skill prizes.
> Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d
> _______________________________________________
> ojAlgo-user mailing list
> ojA...@li... <javascript:;>
> https://lists.sourceforge.net/lists/listinfo/ojalgo-user
>