/**
* The factory method: builds the solver needed to solve the problem (an optimization solver if a
* variable should be minimized or maximized, a classical solver (mac-dbt) for constraint
* problems, or a path-repair or decision-repair solver if explanations should be kept.
*/
public void generateSearchSolver() {
if (null == objective) { // MAC-DBT
strategy = new PalmGlobalSearchStrategy(this);
} else // MAC-DBT + Dynamic Cuts
if (objective instanceof IntDomainVar)
strategy = new PalmBranchAndBound(this, (IntDomainVar) objective, doMaximize);
else if (objective instanceof RealVar)
strategy = new PalmRealBranchAndBound(this, (RealVar) objective, doMaximize);
if (prSize >= 0) { // Decision repair
if (repair == null) repair = new PalmUnsureRepair();
NogoodSConstraint ng = new NogoodSConstraint(intVars.toArray());
post(ng);
if (learn == null) {
learn = new PathRepairLearn(prSize, ng);
} else {
((PathRepairLearn) learn).setMemory(ng);
}
}
// Classical solver tools
if (state == null) state = new PalmState((PalmExplanation) makeExplanation());
if (repair == null) repair = new PalmRepair();
if (learn == null) learn = new PalmLearn();
if (extend == null) extend = new PalmExtend();
// Classical limits
strategy.limits.add(new PalmTimeLimit(strategy, timeLimit));
strategy.limits.add(new NodeLimit(strategy, nodeLimit));
// TODO : limits.add(new relaxLimit());
// Solver should stop at first solution ? TODO : see if useful !
strategy.stopAtFirstSol = firstSolution;
// Attach solver tools
((PalmGlobalSearchStrategy) strategy).attachPalmState(state);
((PalmGlobalSearchStrategy) strategy).attachPalmExtend(extend);
((PalmGlobalSearchStrategy) strategy).attachPalmLearn(learn);
((PalmGlobalSearchStrategy) strategy).attachPalmRepair(repair);
// Attach branchings (with a default one if needed
if (branchings.size() == 0) {
if (varIntSelector == null) varIntSelector = new MinDomain(this);
if (valIntIterator == null && valIntSelector == null) valIntIterator = new IncreasingDomain();
if (prSize < 0)
if (valIntIterator != null)
branchings.add(new PalmAssignVar(varIntSelector, valIntIterator));
else branchings.add(new PalmAssignVar(varIntSelector, valIntSelector));
else if (valIntIterator != null)
branchings.add(new PathRepairAssignVar(varIntSelector, valIntIterator));
else System.err.println("Path repair cannot use valSelector");
}
((PalmGlobalSearchStrategy) strategy).attachPalmBranchings(branchings);
}
/**
* Posts and propagates several decision constraints (that is decisions taken by the solver).
*
* @param constraints The constraints to post.
* @throws ContradictionException
*/
public void propagateAllDecisionsConstraints(List constraints) throws ContradictionException {
// this.palmSolver.incRuntimeStatistic(EXT, 1); move in explore
for (Iterator iterator = constraints.iterator(); iterator.hasNext(); ) {
AbstractSConstraint constraint = (AbstractSConstraint) iterator.next();
this.post(
constraint,
0); // Avant la mise a jour de l'etat sinon la contrainte n'existe pas encore !!
((PalmGlobalSearchStrategy) strategy).getState().addDecision(constraint);
this.propagate();
}
}
/**
* Tries to repair the problem after a PalmContradiction thanks to removing a responsible
* constraint (that is a constraint in the explain of the contradiction).
*
* @throws ContradictionException
*/
public void repair() throws ContradictionException {
((PalmGlobalSearchStrategy) strategy).repair();
}
