Originally posted by: gtoptimizer

Hey all,

Let's say I am running a MIP solve with the default branching strategy, and am using a branching callback function.

If my callback makes calls to CPXstrongbranch, does CPLEX automatically use the strong branching information to update the pseudocosts (as returned by CPXgetcallbackpseudocosts), or are the pseudocosts not affected by the CPXstrongbranch calls?

Thanks!

Originally posted by: RWunderling

Calling CPXstrongbranch() from a user callback does not update the pseudo costs CPLEX is using.

Roland

Originally posted by: gtoptimizer

Thanks for replying Roland.

One more quick question: does running a solve with CPX_VARSEL_STRONG as the branching strategy update the pseudocosts (i.e. does it use the simplex iterations of strong branching to update the pcosts)?

Thanks again!

Originally posted by: RWunderling

With the current CPLEX release, the result of the internal CPXstrongbranch() calls are used to update CPLEX's internal pseudocosts.
However, note that such information, while correct at the moment, may change without notice.  Thus it is advised not to rely on such information for any type of production code.

Roland

Originally posted by: gtoptimizer

Good to know, thanks!