[Coin-bcpdiscuss] Recursivly use of BCP and branching

[Francois Margot]

On Wed, 21 Dec 2005, Simon Spoorendonk wrote:

> We have a few questions about BCP? It is implemented and working, however not without several workarounds. We hope that answers to the following questions could "clean"/speed the code up.
>
> 1. We have several applications using the BCP framework and would like to call one within the other, i.e. during column generation we wish to solve another problem solved with branch-and-cut (both are implemented with BCP). Is this possible in an easy way (not calling an external program, but doing it in memory)?

I don't think this is possible: Bcp is written as a driver, not a library, 
i.e. the "main" routine is not "owned" by the application. Even trying to solve
a sequence of ILPs (without system calls) is challenging.

> 2. Is it possible to do variable generation and cut generation doing strong branching without hacking the strong branch loop of BCP?
> 3. When branching on cuts while column generating, is it possible to do this better than adding a cut for each branch child and fixing the bounds (in select_branching_candidates)? And how are we guaranteed that the cut (algo) is never Removed without setting BCP_IneffectiveConstraints = 0? Should the cuts be added as core cuts?

Sorry, I have never used column generation with Bcp. You will have to wait
for Laci to come back for these two.

Francois