[Coin-discuss] Comments on OSI for CPLEX and Xpress MP

Matthew Galati magala at wnt.sas.com
Wed May 5 15:50:31 EDT 2004


Hi Kish,

>>Is there some overview documentation for OSI? For example, I had to
>>experiment to find out that for solving a MIP problem, I needed to make a
>>call to InitialSolve() first. The tutorial at Leihigh University was very
>>helpful for the linear problems, but it did not show a MIP problem.
>>

The other examples on Lehigh's site might help. Check out "UFL-Cutting
Planes". It should give you a basic idea of how you might start off
solving a MIP by branch-and-cut using OSI. This example deals with a
specific IP and only deals with the root node. For full-blown branch and
cut (or branch and price) you might look at the BCP examples: "Branch
and Cut", "UFL - Branch and Cut", and "AAP - Branch and Price" -
although there is a lot of overhead in learning to use BCP. You might
also want to look at the COIN/Sbb/Samples source for ways to incorporate
CGL for general MIPs.

I agree that more simple examples and documentation explaining them are
greatly needed. This is/was the intention of the site at Lehigh - but I
have not had much time, nor help, to extend it. I am excited to see what
Brady comes up with.

Matt


-- 
Matthew Galati -- Optimization Developer
SAS Institute -- Analytical Solutions / Operations R & D
Office R4112 O: 919-531-0332 F: 919-677-4444
URL: http://sagan.ie.lehigh.edu/mgalati/






More information about the Coin-discuss mailing list