[Coin-discuss] Using Osi/Clp

[Jean-Sebastien Roy]

Hi !

You will find the Coin-OR documentation here:
http://www.coin-or.org/documentation.html

You will notably find the Clp user guide here:
http://www.coin-or.org/Clp/userguide/index.html

And some nice tutorials here:
http://coral.ie.lehigh.edu/~coin/

The precise syntax for all the operations you are looking for is 
available in the Doxygen documentation, included with Coin. You can 
build it locally or have look at it here:
http://www.coin-or.org/Doxygen/

For the precise operations you seek :
(disclaimer: I'm no Coin expert)

 > 1. Select primal or dual simplex algorithm

Select dual simplex:
(assuming solver is a OsiSolverInterface)
solver.setHintParam(OsiDoDualInInitial,true,OsiHintTry);

 > 2. Add a column to the LP matrix
 > 3. Add a row to the LP matrix
 > 4. Delete and replace a row of the LP matrix
 > 5. Replace elements of the LP matrix

Look here:
http://www.coin-or.org/Doxygen/Osi/class_osi_solver_interface.html
for addCols, addRows, and consorts.

 > 6. Post solve after modifications

solver.resolve()

 > 6. Scale LP problem

solver.setHintParam(OsiDoScale,true,OsiHintTry)

 > 7. Save and load an optimal basis

You may have a look at the getBasisStatus/setBasisStatus methods.

 > 8. Direct Osi/Clp messages

You may need to write your own CoinMessageHandler and change the one 
used by Clp using:
solver.passInMessageHandler(myHandler)

Regards,

Jean-Sebastien


Edgardo Fuchs wrote:
> Dear Coin list members,
> 
> I wish to use Osi/Clp within a stochastic optimization model to solve a 
> long-term hydro-thermal power generation dispatch problem.
> The model was developed using OSL, but I want to migrate it to Osi/Clp.
> 
>  >From the example "build.cpp" it is clear how to construct a model from 
> scratch and solve it. But I have not found the way to perform additional 
> operations required by the dispatch model.
> Could you please give some hints or examples on how to perform the 
> following operations using Osi/Clp?
> 
> 1. Select primal or dual simplex algorithm
> 2. Add a column to the LP matrix
> 3. Add a row to the LP matrix
> 4. Delete and replace a row of the LP matrix
> 5. Replace elements of the LP matrix
> 6. Post solve after modifications
> 6. Scale LP problem
> 7. Save and load an optimal basis
> 8. Direct Osi/Clp messages
> 
> Thank you in advance.
> Sincerely,
> 
> Edgardo Fuchs
> KAS Ingeniería
> 
> -- 
> 
> Edgardo Fuchs
> 
> Santiago, Chile
> 
> Tel: +56 (2) 435 0090
> Cel: +56 9837 8433
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Coin-discuss mailing list
> Coin-discuss at list.coin-or.org
> http://list.coin-or.org/mailman/listinfo/coin-discuss