[SCIP] problem with objective value

[sakib mondal]

Dear Benny,


Thanks a lot for your suggestion.  I found out that there was an issue with my implementation of  constraint handler class (the way z was being passed).  It seems to work fine now.


Regards

Sakib




________________________________
From: Benjamin Müller <benjamin.mueller at zib.de>
Sent: Tuesday, May 30, 2017 6:28 AM
To: sakib mondal; scip at zib.de
Subject: Re: [SCIP] problem with objective value

Dear Sakib,

how large is the difference between what you expect and what SCIP is
returning? Note that SCIP is using feasibility tolerances for deciding
whether a constraint is satisfied or not. This could cause a difference
in the order of 10^-6.

It would be nice if you could send me your python model, in case your
objective values differ quite a lot.

Cheers,
Benny

On 05/24/2017 02:48 PM, sakib mondal wrote:
> Hi,
>
>
> I have a problem in which due to certain transformation, I have
> rewritten the objective function as a constraint.
>
>
> Original problem is max exp(cx) st constraint set C1.
>
>
> I rewrite it as max z st exp(cx)=z and constraint set C1.
>
>
> Scip solves it without any error or warning message. However, when I
> check the objective value (model.getObjVal() ), it is always giving a
> value which is different from the actual value (I compute it from the
>  optimum x value).  Even if I change the problem parameters,
> model.getObjVal() gives the same value.
>
>
> Also checked that model.getObjVal() is same as model.getVal(z)
>
>
>
> Wondering what could be the problem.  Thanks a  lot for the help.
>
>
> Regards
>
> Sakib
>
>
>
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> Scip at zib.de
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>

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______________________________
Benjamin Müller
Zuse Institute Berlin
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