@Override
public boolean init() {
boolean init = super.init();
ObjectiveManager<IntVar, Integer> om = mSolver.getObjectiveManager();
this.objectiveManager = om;
if (objectiveManager.getPolicy() == ResolutionPolicy.SATISFACTION) {
throw new UnsupportedOperationException("HBFS is not adapted to satisfaction problems.");
}
isMinimization = objectiveManager.getPolicy() == ResolutionPolicy.MINIMIZE;
return init;
}
/**
* Extract the open right branches from the current path until it reaches the i^th decision of
* _unkopen
*
* @param searchLoop the search loop
* @param i the index of the decision, in _unkopen, that stops the loop
*/
private void extractOB(SearchLoop searchLoop, int i) {
Decision stopAt = _unkopen.get(i).getPrevious();
// then, goes up in the search tree, and detect open nodes
searchLoop.mSolver.getEnvironment().worldPop();
Decision decision = searchLoop.decision;
int bound;
while (decision != stopAt) {
bound =
isMinimization
? objectiveManager.getObjective().getLB()
: objectiveManager.getObjective().getUB();
if (decision.hasNext() && isValid(bound)) {
opens.add(new Open(decision, bound, isMinimization));
}
searchLoop.decision = searchLoop.decision.getPrevious();
decision.free();
decision = searchLoop.decision;
searchLoop.mSolver.getEnvironment().worldPop();
}
}
/**
* If the bound of an O.R.B exceed the best known so far, it returns false.
*
* @param bound the current bound of an O.R.B.
* @return true if bound is valid wrt the best known so far.
*/
private boolean isValid(int bound) {
return isMinimization
? bound < objectiveManager.getBestUB()
: bound > objectiveManager.getBestLB();
}