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

[Matthew Galati]

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/