[Coin-discuss] osi cplex implementation not MIP friendly

[Jevan Saks]

First, let me thank the creators and contributors for their great work
in making such a useful and powerful library!  I'm using cplex 7.1 and
COIN from 7/27/03.  I noticed a small bug in the cplex solver interface.
The problem is that after branchAndBound completes successfully,
getObjValue doesn't return the objective of the MIP solution.  

There is a variable, probtypemip_, that is checked a number of times but
never changes.  At the end of the if(probtypemip_) block in switchToLP
and switchToMIP, add probtypemip_ = false/true, respectively.  

This fixes retrieving the objective, but checking isProvenOptimal
returns false, and isProvenPrimalInfeasible and isProvenDualInfeasible
both print out errors: " CPLEX Error  1217: No solution exists."  I'm
not sure if this is a bug or a feature.

In any event, keep up the good work!

-Jevan