[Cbc] Improving performance for binary model

[Haroldo Gambini Santos]

Forrest,

Could this recursive presolve that you did manually be implemented 
programmatically as an option ?

Em 11/23/19 7:26 AM, John Forrest escreveu:
> My guess is that Cbc is very bad at handling symmetry.  There is a lot 
> of symmetry and trying some of the pathetic ways that Cbc can deal 
> with symmetry I can get a solution of 296773 fairly quickly, but after 
> an hour it does not seem to be closing the gap.  The other area where 
> Cbc is failing somewhat is preprocessing - if I export the model 
> several times (each time doing presolve) then I can make it smaller - 
> this obviously should be able to be done in one go.
>
> John Forrest
>
> On 22/11/2019 15:44, Rui Patrocínio wrote:
>> Hi,
>>
>>   I'm trying to solve one instance of a problem that is taking a long 
>> time to obtain a good solution. Since all variables are binary, 
>> probing and implication cuts are doing some work and RINS and Vnd are 
>> apparently also improving solutions. For other instances of the 
>> problem we are solving, CBC has an acceptable performance but for 
>> this instance apparently there's something going wrong (~20 seconds 
>> to get the optimum solution with a commercial solver versus never 
>> getting the optimum solution with CBC).
>>
>>   If someone can take a look at the model and give me a hint of what 
>> is going on, I would appreciate it.
>>
>>   The model is at 
>> https://drive.google.com/open?id=1bd4jWONmoyAKIi0oLa-AU-ZTu7_8qhb6
>>
>> -- 
>> SISCOG - Sistemas Cognitivos, SA
>>
>> *Rui Patrocínio*
>>
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>>
>
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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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