[Osi] Bug in Osi?

[Stefan Vigerske]

Hi,

I remember having put in this assert some years ago.
The assert makes sense to me. If the basis status is at-upper-bound, 
then the upper bound should not be infinity.
Instead of taking it out, it would be better to nail down the actual bug.

Stefan


On 04/01/2013 06:22 PM, John Forrest wrote:
> I noticed this recently when using trunk.  I took out assert in
> Osi/trunk and could see no harm in it.
>
> It should not be a fatal error.  I don't really have time to track it
> down.  It must be a minor bug in one of the CoinPresolve.... postsolvers.
>
> John Forrest
> On 01/04/13 16:28, Horand Gassmann wrote:
>> Hi,
>>
>> I am trying to solve a small aggregate planning model. (AMPL model and
>> data files attached.) The LP relaxation works fine, but when I add an
>> integrality constraint on the first set of variables (number_workers),
>> I get an assert error:
>>
>> ../../../../Osi/src/Osi/OsiPresolve.cpp:507: virtual void
>> OsiPresolve::postsolve(bool): Assertion `status !=
>> CoinWarmStartBasis::atUpperBound || originalModel_->getColUpper()[i] <
>>  infty' failed.
>>
>> What causes the error is unclear to me. I do not provide a starting
>> basis, so I wouldn't expect the presolver to even go there. Is this a
>> bug? Does the presolver require finite upper bounds? Any ideas?
>>
>> Thanks
>>
>> gus
>> -------------------------------------------------------
>>
>> Horand I. Gassmann, Professor
>>
>> Kenneth C. Rowe School of Business, Dalhousie University
>> 6100 University Avenue, PO Box 15000
>> Halifax, Nova Scotia, Canada, B3H 4R2
>> ph. (902) 494-1844
>> fax (902) 494-1107
>>
>> http://myweb.dal.ca/gassmann/
>>
>>
>> ----- End forwarded message -----
>>
>>
>> -------------------------------------------------------
>>
>> Horand I. Gassmann, Professor
>>
>> Kenneth C. Rowe School of Business, Dalhousie University
>> 6100 University Avenue, PO Box 15000
>> Halifax, Nova Scotia, Canada, B3H 4R2
>> ph. (902) 494-1844
>> fax (902) 494-1107
>>
>> http://myweb.dal.ca/gassmann/
>>
>>
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>
>
>
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