[Coin-discuss] accessing the Clp solver from Cbc/Clp

[Kish Shen]

Lou,
On Wednesday 28 June 2006 18:25, Lou Hafer wrote:
> Kish,
>
> > For the interface to OSI/Coin solvers that I am developing, I am hoping
> > to do most things via the OSI interface, so that we can access as wide a
> > range of solvers as possible, and then provide `specialised' code to
> > improve performance/functionality for specific solvers, such as Cbc/Clp.
>
> 	You're entering relatively uncharted territory here.  (See the earlier
> thread in coin-discuss about cbc vs.  cbc-generic, from June 22.)  Given
> demand from Coin users, support for other OSIs can move up the priority
> scale, but right now it's low and occasionally broken.  Getting this right
> will require effort at both the Cbc and OsiXXX levels.  Your feedback will
> be valuable here.
>
> 							Lou
>
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I guess for my specific case, I don't really need OSI CPLEX or XPRESS, as our 
own interface already directly use the CPLEX and XPRESS C API already. 
I have actually been trying out the OSI on and off for the last two years, but 
the first time I tried it, I mainly tried using GLPK, and I was somewhat 
disappointed with the performance. Last year I tried again, and I was quite 
impressed with the improvements and the performance of CLP/CBC, and so now I 
am doing the proper conversion of our interface. 

In terms of functionality, it would be quite nice if the difference between 
the linear solver and CBC be more hidden, as I need to solve both linear and 
MIP (and actually also QP and MIQP) problems using one solver. As things 
stands now, I need to extract both the CBC and CLP model pointers to do 
different things. More support for MIP in the OsiSolverInterface would be 
useful.

Cheers,

Kish