[SCIP] Stopping at the next best solution than the one passed

[Meenarli Sharma]

Hello everyone,

Some more information about my problem.

I am using SCIP (scipampl) with ampl. I iteratively call scip to solve a
convex MINLP. I want to pass objective value of (i)th iteration to (i+1)th
iteration and want scip (at (i+1)th iteration) to stop when it finds a
solution with better objective value than the one passed.

I tried modifying (automatically from ampl) the parameter limits/objective
in the setting file (scip.set) before every iteration. But I get the
warning, WARNING: unknown parameter <limits/objective>.

I have cross checked that I am not making any syntax error while writing
the parameters. Also, I am not getting any such warning when I am not
having this parameter in the settings file.

Kindly let me know if there is any suggestion/comment.

Regards,
~Meenarli




> Hello Ambros,
>
> Thank you for the reply. I have already tried this parameter but I got the
> error: WARNING: unknown parameter <limits/objective>. Any clue why is it
> happening?
>
> Regards,
> ~Meenarli
>
>
>  already > Hi Meenarli,
>>
>> "limits/objective" is the parameter you are looking for.
>>
>> You easily inspect a list of all parameters with documentation yourself
>> in a file by typing "set save scipparams.set" in the interactive shell.
>>
>> Best,
>> Ambros
>>
>>
>> Am 05.06.2018 um 19:12 schrieb Meenarli Sharma:
>>> Hello Gerald,
>>>
>>> Thank you very much for the prompt reply. Is there any option (to be
>>> written in scip.set file) for passing an upper bound on the objective
>>> value and then stop at the first solution with objective value smaller
>>> than the one passed?
>>>
>>> Thank you again.
>>>
>>> Regards,
>>> ~Meenarli
>>>
>>>   > Dear Meenarli,
>>>>
>>>> you want to set limits/bestsol to 1.
>>>>
>>>> Best,
>>>> Gerald
>>>>
>>>> On 05.06.2018 17:48, Meenarli Sharma wrote:
>>>>> Hello everyone,
>>>>>
>>>>> I am using SCIP as a solver with AMPL. I pass a feasible solution and
>>>>> want
>>>>> SCIP to stop when it finds a solution better than the one that is
>>>>> being
>>>>> passed. How can this be achieved?
>>>>>
>>>>> I tried limiting the number of feasible solutions but it didn't help
>>>>> as
>>>>> heuristics found that many solutions - none of them is better than
>>>>> what
>>>>> is
>>>>> being passed in this case- and it stopped. I can try changing the
>>>>> limit
>>>>> on
>>>>> solutions until I find a better one but I am forced to believe there
>>>>> must
>>>>> be a better way to do it.
>>>>>
>>>>> Any help will be highly appreciated.
>>>>>
>>>>> Thanks and regards,
>>>>> ~Meenarli
>>>>>
>>>>> _______________________________________________
>>>>> Scip mailing list
>>>>> Scip at zib.de
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>>>>
>>>>
>>>
>>>
>>> _______________________________________________
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>>
>> --
>> Ambros Gleixner, Research Group Mathematical Optimization Methods at
>> Zuse Institute Berlin, http://www.zib.de/gleixner
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