[Scip] epsilon for functions isPositive, isZero, etc

[Matthias Miltenberger]

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
>
>

-- 
\__________________

Matthias Miltenberger
Zuse Institute Berlin
Takustr. 7, 14195 Berlin
www.zib.de/miltenberger
miltenberger at zib.de
+49 (30) 841 85-245


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