[Cgl] CGL Design - suggested CoinSnapshot

[Matthew Saltzman]

On Tue, 19 Dec 2006 fmargot at andrew.cmu.edu wrote:

> On Fri, 15 Dec 2006 mjs at ces.clemson.edu wrote:
>
>> The cut application method has to be on the solver side, but I don't see 
>> (after only a few minutes thought) why the cutlist manager couldn't be on 
>> the cut side.  The application method could be (should be) a clean 
>> interface.
>
> The cutlist manager could be on the cut side. The problem is that it is now 
> on
> the solver side and moving it to the cut side would require lots of changes
> in existing code (other than Cgl). It does not mean that it should not be 
> done, but I don't think it should be high on the to-do list for now.
>
>> I understand that CGL needs a problem representation that is independent of 
>> a solver, but I still sort of lean toward putting it in something like 
>> OsiCglSolverInterface.  I think it might be useful for OSI to support such 
>> a representation anyway.  One would be able to do everything with it except 
>> solve it and extract solutions.
>
> Are there plans for this in Osi in the near future? Are there any such 
> concept
> planned in Osi2?

That's one of the main design plans in OSI2.  The instance representation 
will be decoupled from the solver so you can have an instance with no 
solver attached.  A solver association lives only so long as the user 
wants to manipulate the instance using solver actions (such as generating 
a solution, but not merely modifying the instance).  There are significant 
details still to be worked out, though.

For OSI now, it seems like this discussion presents the opportunity to 
consider adding a no-solver SI for this use (OsiNoSolverInterface?).

-- 
 		Matthew Saltzman

Clemson University Math Sciences
mjs AT clemson DOT edu
http://www.math.clemson.edu/~mjs