[Cbc] Why unmaintained OsiCbc?

[Haroldo Gambini Santos]

My impression is that OSI interfaces are only well maintained for linear 
programming solvers. Why ?  MIP solvers have much more configuration 
options and OSI 1.0 did not evolve to cope with these things. More 
specifically to OsiCbc,  I think that we don't have anyone working 
actively on it. I think that OSI 2.0 developers are investing now more 
on MIP.

Regarding the use of CbcMain0 and CbcMain1 instead of branch and bound 
of CbcModel:  the performance of the pure branch and bound (without cuts 
and well tuned heuristics) is horrible. A good set of parameter settings 
is maintained in CbcMain0 and CbcMain1  ( the recommended way of calling 
cbc, which includes the same configuration of the standalone command 
line solver).

Cheers

On 17/11/2019 19:10, Jan-Willem Goossens wrote:
>
> Hi, a few comment threads discuss how OsiCbc is unmaintained, but I 
> couldn’t understand why?
>
> For example, 
> https://github.com/coin-or/CyLP/issues/34#issuecomment-185988123
>
> My code (https://github.com/coin-or/SONNET) is also calling solvers 
> via Osi, including OsiCbc. In case of OsiCbc, Sonnet calls CbcSolver 
> to apply some of the ‘special sauce’ mentioned in the comments above.
>
> Also, why not use CbcSolver in OsiCbc instead of the plain 
> branchAndBound, like the comment
>
> “To enjoy the full performance of Cbc, use the CbcSolver interface.” 
> mentions?
>
> Is the best way forward to plan to stop using OsiCbc, or to try to get 
> OsiCbc maintained?
>
> Regards,  Jan-Willem
>
>
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-- 
=============================================================
Haroldo Gambini Santos
Computing Department
Universidade Federal de Ouro Preto - UFOP
email: haroldo at ufop.edu.br
home/research page: www.decom.ufop.br/haroldo


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