[Bonmin] Last solution not being saved

[Pierre Bonami]

Dear Rodrigo,
Being able to give an indication of why an MINLP is infeasible would be very
nice, but unfortunately I think it is a pretty difficult problem, and I
don't see anything automatic which can be put in Bonmin without a
substantial amount of work.

If you have a model which is infeasible and you think should not be, I think
that a good way to start is to add artificial variables for the constraints
and try to minimize constraint violation. You can then see which of the
constraints seems to give the most difficulties.

Cheers,
Pierre
On 11/21/06, Rodrigo López Negrete de la Fuente <soyrush at gmail.com> wrote:
>
> Dear Pierre,
>
> Now that you put it that way, I am not so sure...Although it would be
> helpful to try and find where the unfeasibilities are, or to get some extra
> information on where my problem might be. What do you think?
>
> cheers,
>   Rodrigo
>
> On 11/21/06, Pierre Bonami <pierre.bonami at gmail.com> wrote:
> >
> > Dear Rodrigo,
> > I am not sure what the behavior should be. Since there is no known
> > solution in this case any values are wrong.
> >
> > Anyway, if the values of the last feasible Non-Linear program computed
> > are usefull to you, I can try to plug them in. (Is that what you want?
> >
> > Cheers,
> > Pierre
> >
> > On 11/19/06, Rodrigo López Negrete de la Fuente < soyrush at gmail.com>
> > wrote:
> >
> > > Hello everybody,
> > >
> > > I've been using bonmin through its ampl interfase. I've noticed that
> > > when the solver ends with an infeasible problem, the values of the variables
> > > are not updated, ( i.e., the values of the returned variables are the
> > > same as the initial values I supplied). I was wondering if this is normal
> > > behavior or if there is a way to get the last feasible (NLP) solution
> > > calculated.
> > >
> > > I'm using the BB method...  Although I've seen this behavior with the
> > > other methods as well.
> > >
> > > Thanks all,
> > >   Rodrigo.
> > >
> > > --
> > > Rodrigo López Negrete
> > > http://muon.blogdns.org/~rush/ <http://muon.blogdns.org/%7Erush/>
> > > _______________________________________________
> > > Bonmin mailing list
> > > Bonmin at list.coin-or.org
> > > http://list.coin-or.org/mailman/listinfo/bonmin
> > >
> > >
> > >
> >
>
>
> --
> Rodrigo López Negrete
> http://muon.blogdns.org/~rush/ <http://muon.blogdns.org/%7Erush/>
>
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