Impacts are obtained from observations of instantiation during the search tree. However, before starting the search no impacts are available and this can lead to bad choices of variables and values at the beginning of the search.

To initialize impacts a goal is available that performs a dichotomous search on each variable. The goal is:

IloGoal IloInitializeImpactGoal(IloEnv env, IloInt depth = -1);

It performs a search on each variable on which impacts were required when the function solver.use(IlcImpactInformation(env, vars)) was called.

The parameter depth controls the depth of the dichotomous search. The larger the depth, the more accurate the impact values are. When depth equals -1, there is no limit imposed on the depth of dichotomy.