[Couenne] Lower/Upper bounds variables

[Luca Mencarelli]

Dear Pietro,

First of thanks very much for the answer. However in the .sol file I found
the same values as the one I obtain via the display command. But when I
recompute
the objective function with these values, it is less than the upper bound
provided
by Couenne.

Best,
Luca

-- 

Luca Mencarelli
PhD Candidate at LIX, Ecole Polytechnique
91128 Palaiseau CEDEX, France
Office: 2072 (Bâtiment Alan Turing, second floor)
LIX e-mail address: mencarelli at lix.polytechnique.fr
INRIA e-mail address:  luca.mencarelli at inria.fr



> Hi Luca,
>
> when Couenne stops before closing the gap, the best feasible MINLP
> solution found (if any) is saved in a file with the same name as the
> input file but with extension .sol (which is the format read by AMPL).
> So the answer is yes for the upper bound if at least one solution is
> found.
>
> However, this does not make much sense for the lower bound, given that
> it's obtained by a relaxation of the MINLP (and would hence be
> infeasible) and is related to the whole branch-and-bound search tree
> rather than a specific subproblem. Hence no solution is available for
> the lower bound.
>
> Hope this helps,
> Pietro
>
>
> On Mon, May 18, 2015 at 11:05 AM, Luca Mencarelli
> <mencarelli at lix.polytechnique.fr> wrote:
>> Hi,
>>
>> If Couenne did not succeed in solving a problem to optimality, it's
>> possible to
>> retrieve the values of the decision variables corresponding to the lower
>> and to
>> the upper bounds provided by the solver?
>>
>> Thanks. Best,
>> Luca
>>
>> --
>> Luca Mencarelli
>> PhD Candidate at LIX, Ecole Polytechnique
>> 91128 Palaiseau CEDEX, France
>> Office: 2072 (Bâtiment Alan Turing, second floor)
>> E-mail address: mencarelli at lix.polytechnique.fr
>>
>>
>>
>>
>>
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>