[Scip] epsilon for functions isPositive, isZero, etc

[Alessia Violin]

Hello Matthias,

thanks! Is there a function to change the epsilon once for all those 
functions? it would be quicker to test different values!

Alessia


On 01/27/2014 11:59 AM, Matthias Miltenberger wrote:
> Hi Alessia,
>
> SCIP uses 1e-9 as default epsilon for these functions. It can be changed
> to a value in the range of 1e-20 to 1e-3.
>
> best
> Matthias
>
> On 27.01.2014 11:17, Alessia Violin wrote:
>> Hello!
>>
>> I was wondering which is the "epsilon" used in the functions
>> SCIPisPosite, isZero, isEQ, etc? I tried to find this information in the
>> developer's manual but I didn't succeed.
>>
>> I have a branch-and-cut-and-price code with quite a lot of other things
>> (stabilisation, heuristics, ...), and if the epsilon is too small the
>> convergence of column generation is very slow, and if it's too big there
>> are some particular configurations of parameters for which optimal
>> columns are not generated. Moreover this also depends on the magnitude
>> of the data for different set of instances and I am trying to figure out
>> the best epsilon to use.
>>
>> Thanks in advance!
>>
>> Alessia
>>
>>

-- 
Alessia Violin
Service Graphes et Optimisation Mathématique (G.O.M.)
Université Libre de Bruxelles
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Email: aviolin at ulb.ac.be
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