[Osi] milp support in OSI
Kipp Martin
kmartin at chicagobooth.edu
Thu Apr 23 13:47:24 EDT 2009
Hi Matt:
>
> I've often thought that the OS spec would be a good starting point for
> this discussion. I need to look into it some more, though.
There are four aspects to the OS spec:
1. OSInstance (along with readers and writers) -- the API to build
and/or access a very general model instance. It has get, set, and
calculate (including forward and backward AD calls) methods.
2. OSOption (along with readers and writers) -- the API for solver options
3. OSResult (along with readers and writers) -- the API for solver results
4. OSModification -- the API for addition / modification / deletion.
The first three are done. The last is obviously the most difficult and
we did not want to start without help/input/guidence/marching orders
from others (like the Osi mailing list).
Cheers
>
>> Cheers
>>>> --Laci
>>>>
>>>> On Thu, 23 Apr 2009, Matthew Galati wrote:
>>>>
>>>>> Currently OSI does support the branchAndBound function to solve a MILP.
>>>>> However, I don't see any access methods for MILP statistics afterwards (or
>>>>> any other MILP-type manipulation methods). Is there any intention to add
>>>>> this? For example, how do I get the number of nodes used, the gap, how do I
>>>>> set options specific to MILP for say, Cplex or Xpress calls?
>>>>>
>>>>> I can always cast an Osi to an OsiCpx and then get CpxLp and CpxEnv ptrs and
>>>>> then use Cpx directly -- but obviously all of this defeats the purpose of
>>>>> having OSI.
>>>>>
>>>>> Thanks,
>>>>> Matt
>>>>>
>>>> _______________________________________________
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>>>> Osi at list.coin-or.org
>>>> http://list.coin-or.org/mailman/listinfo/osi
>>
--
Kipp Martin
Visiting Professor
University of Cincinnati
College of Business
Dept. of QAOM
525 Lindner Hall
Cincinnati, OH 45221-0130
513-556-0404
kipp.martin at chicagogsb.edu
http://homepages.uc.edu/~martinrk/
https://projects.coin-or.org/OS
http://www.coin-or.org
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