[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
>>>> --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
>>>> _______________________________________________
>>>> Osi mailing list
>>>> 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


kipp.martin at chicagogsb.edu

More information about the Osi mailing list