The GCG Branching Rules

Branching Rules describe how one can branch in a given node in the Branch-and-Bound tree. For example, one can branch on constraints or on a set of variables all at once. Adjusting the branching rule according to your problem will be done automatically by GCG and can significantly influence the runtime required to solve it.

List of Branching Rules

We currently offer 3 different branching rules, as well as one empty branching rule to coordinate the branching process between SCIP and GCG.

Vanderbeck Generic Branching
branching rule for original problem in GCG while real branching is in the master
Original Variable Branching
branching rule to branch on integral variables of the original problem which were assigned a fractional solution value
Ryan Foster Branching
branching rule for original problem in GCG implementing the Ryan and Foster branching scheme

Descriptions of those and their code documentation can be found here.

Adding own Branching Rules

If you want to add your own branching rules, i.e. define exactly how to branch on variables, please consider our "How to add" for that.

How to add branching rules & selection heuristics