private boolean branchAndBoundHelper(MetaVariable metaVariable) {
if (metaVariable == null) return false;
preBacktrack();
if (this.g.getRoot() == null) this.g.addVertex(currentVertex);
ConstraintNetwork cn = metaVariable.getConstraintNetwork();
logger.fine("Solving conflict: " + metaVariable);
ConstraintNetwork[] values = metaVariable.getMetaConstraint().getMetaValues(metaVariable);
if (metaVariable.getMetaConstraint().valOH != null)
Arrays.sort(values, metaVariable.getMetaConstraint().valOH);
if (values == null || values.length == 0) {
this.g.addEdge(new NullConstraintNetwork(null), currentVertex, new TerminalNode(false));
logger.fine("Failure... (1)");
} else {
for (ConstraintNetwork value : values) {
if (animationTime != 0) {
try {
Thread.sleep(animationTime);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
logger.fine("Trying value: " + Arrays.toString(value.getConstraints()));
if (hasConflictClause(value)) continue;
this.addResolver(cn, value);
setUpperBound();
// System.out.println("test: " + "U: " + getUpperBound() + " L: " + getLowerBound());
if (getUpperBound() <= getLowerBound()) {
this.retractResolver(cn, value);
continue;
}
logger.fine("Success...");
metaVariable.getMetaConstraint().markResolvedSub(metaVariable, value);
MetaVariable newCon = this.getConflict();
if (newCon != null) {
this.g.addEdge(value, currentVertex, newCon);
currentVertex = newCon;
}
if (newCon == null) setLowerBound();
if (branchAndBoundHelper(newCon)) return true;
logger.fine("Retracting value: " + Arrays.toString(value.getConstraints()));
this.retractResolver(cn, value);
logger.fine("Failure... (2)");
}
}
resetFalseClause();
logger.fine("Backtracking...");
currentVertex = this.g.getParent(currentVertex);
postBacktrack(metaVariable);
return false;
}
/**
* This backtrack method uses serialization to back up {@link ConstraintNetwork}s before
* branching. This allows to backtrack without propagation - but is very memory intensive. In
* practice, this does not work on reasonably sized problems.
*/
private boolean backtrackHelperWithSerialization(MetaVariable metaVariable) {
preBacktrack();
if (this.g.getRoot() == null) this.g.addVertex(currentVertex);
ConstraintNetwork mostProblematicNetwork = metaVariable.getConstraintNetwork();
logger.fine("Solving conflict: " + metaVariable);
ConstraintNetwork[] values = metaVariable.getMetaConstraint().getMetaValues(metaVariable);
if (metaVariable.getMetaConstraint().valOH != null && values != null)
Arrays.sort(values, metaVariable.getMetaConstraint().valOH);
if (values == null || values.length == 0) {
this.g.addEdge(new NullConstraintNetwork(null), currentVertex, new TerminalNode(false));
logger.fine("Failure (1)...");
} else {
for (ConstraintNetwork value : values) {
if (animationTime != 0) {
try {
Thread.sleep(animationTime);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
String valString = "";
if (value.getVariables().length != 0)
valString += "Vars = " + Arrays.toString(value.getVariables());
if (value.getConstraints().length != 0)
valString += " Cons = " + Arrays.toString(value.getConstraints());
logger.fine("Trying value: " + valString);
this.backedUpCNs.add(backupCNs(this));
/** * PRINT INFO ** */
/*
long sizeOfBackup = 0;
for (HashMap<ConstraintSolver,byte[]> oneHM : backedUpCNs) {
for (byte[] oneCN : oneHM.values())
sizeOfBackup += oneCN.length;
}
DecimalFormat df = new DecimalFormat("#.##");
logger.info("Current backup size: " + df.format((sizeOfBackup/1024.00)) + " KB");
*/
/** * END PRINT INFO ** */
if (this.addResolver(mostProblematicNetwork, value)) {
this.resolvers.put(mostProblematicNetwork, value);
this.metaVarsToMetaCons.put(mostProblematicNetwork, metaVariable.getMetaConstraint());
this.resolversInverseMapping.put(value, mostProblematicNetwork);
this.counterMoves++;
logger.fine("Success...");
metaVariable.getMetaConstraint().markResolvedSub(metaVariable, value);
MetaVariable newConflict = this.getConflict();
if (newConflict == null || breakSearch) {
this.g.addEdge(value, currentVertex, new TerminalNode(true));
breakSearch = false;
return true;
}
// addEdege(e,v,v)
this.g.addEdge(value, currentVertex, newConflict);
currentVertex = newConflict;
if (backtrackHelper(newConflict)) return true;
logger.fine("Retracting value: " + Arrays.toString(value.getConstraints()));
// this.retractResolver(mostProblematicNetwork, value);
this.restoreCNs();
this.retractResolverSub(mostProblematicNetwork, value);
this.resolvers.remove(mostProblematicNetwork);
this.metaVarsToMetaCons.remove(mostProblematicNetwork);
this.resolversInverseMapping.remove(value);
this.counterMoves--;
} else {
this.g.addEdge(value, currentVertex, new TerminalNode(false));
logger.fine("Failure... (2)");
}
}
}
logger.fine("Backtracking...");
currentVertex = this.g.getParent(currentVertex);
postBacktrack(metaVariable);
return false;
}
private boolean backtrackHelper(MetaVariable metaVariable) {
preBacktrack();
if (this.g.getRoot() == null) this.g.addVertex(currentVertex);
ConstraintNetwork mostProblematicNetwork = metaVariable.getConstraintNetwork();
logger.fine("Solving conflict: " + metaVariable);
ConstraintNetwork[] values = metaVariable.getMetaConstraint().getMetaValues(metaVariable);
if (values != null) for (ConstraintNetwork value : values) value.setAnnotation(metaVariable);
if (metaVariable.getMetaConstraint().valOH != null && values != null) {
// System.out.println("SORTING with " + metaVariable.getMetaConstraint().valOH.getClass());
Arrays.sort(values, metaVariable.getMetaConstraint().valOH);
}
if (values == null || values.length == 0) {
this.g.addEdge(new NullConstraintNetwork(null), currentVertex, new TerminalNode(false));
logger.fine("Failure (1)...");
} else {
for (ConstraintNetwork value : values) {
if (animationTime != 0) {
try {
Thread.sleep(animationTime);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
String valString = "";
if (value.getVariables().length != 0)
valString += "Vars = " + Arrays.toString(value.getVariables());
if (value.getConstraints().length != 0)
valString += " Cons = " + Arrays.toString(value.getConstraints());
logger.fine("Trying value: " + valString);
if (this.addResolver(mostProblematicNetwork, value)) {
this.resolvers.put(mostProblematicNetwork, value);
this.metaVarsToMetaCons.put(mostProblematicNetwork, metaVariable.getMetaConstraint());
this.resolversInverseMapping.put(value, mostProblematicNetwork);
this.counterMoves++;
logger.fine("Success...");
metaVariable.getMetaConstraint().markResolvedSub(metaVariable, value);
MetaVariable newConflict = this.getConflict();
if (newConflict == null || breakSearch) {
this.g.addEdge(value, currentVertex, new TerminalNode(true));
breakSearch = false;
return true;
}
// addEdege(e,v,v)
this.g.addEdge(value, currentVertex, newConflict);
currentVertex = newConflict;
if (backtrackHelper(newConflict)) return true;
logger.fine("Retracting value: " + Arrays.toString(value.getConstraints()));
this.retractResolver(mostProblematicNetwork, value);
this.resolvers.remove(mostProblematicNetwork);
this.metaVarsToMetaCons.remove(mostProblematicNetwork);
this.resolversInverseMapping.remove(value);
this.counterMoves--;
} else {
this.g.addEdge(value, currentVertex, new TerminalNode(false));
logger.fine("Failure... (2)");
}
}
}
logger.fine("Backtracking...");
currentVertex = this.g.getParent(currentVertex);
postBacktrack(metaVariable);
return false;
}