/**
* Goal-driven recursive (depth-first, exhaustive) search with backtracking
*
* @param problem
* @param algorithm
* @param subtaskRelsInPath
* @param depth
*/
private boolean subtaskPlanningImpl(
PlanningContext context,
Set<Rel> relsWithSubtasks,
EvaluationAlgorithm algorithm,
LinkedList<Rel> subtaskRelsInPath,
int depth) {
Set<Rel> relsWithSubtasksCopy = new LinkedHashSet<Rel>(relsWithSubtasks);
Set<Rel> relsWithSubtasksToRemove = new LinkedHashSet<Rel>();
boolean firstMLB = true;
// start building Maximal Linear Branch (MLB)
MLB:
while (!relsWithSubtasksCopy.isEmpty()) {
if (isSubtaskLoggingOn()) {
String print = p(depth) + "Starting new MLB with: ";
for (Rel rel : relsWithSubtasksCopy) {
print +=
"\n" + p(depth) + " " + rel.getParent().getFullName() + " : " + rel.getDeclaration();
}
/*
print += "\n" + p( depth ) + " All remaining rels in problem:";
for ( Rel rel : problem.getAllRels() ) {
print += "\n" + p( depth ) + " " + rel.getParentObjectName() + " : " + rel.getDeclaration();
}
print += "\n" + p( depth ) + "All found variables: ";
for ( Var var : problem.getFoundVars() ) {
print += "\n" + p( depth ) + " " + var.toString();
}
*/
logger.debug(print);
}
// if this is a first attempt to construct an MLB to solve a subtask(i.e. depth>0),
// do not invoke linear planning because it has already been done
if ((depth == 0) || !firstMLB) {
boolean solvedIntermediately = linearForwardSearch(context, algorithm, true);
// Having constructed some MLBs the (sub)problem may be solved
// and there is no need in wasting precious time planning unnecessary branches
if (solvedIntermediately
&& ( // on the top level optimize only if computing goals
(depth == 0 && !computeAll)
// otherwise (inside subtasks) always optimize
|| (depth != 0))) {
// If the problem is solved, optimize and return
if (!isOptDisabled) Optimizer.optimize(context, algorithm);
return true;
}
} else {
firstMLB = false;
}
// or children
OR:
for (Iterator<Rel> subtaskRelIterator = relsWithSubtasksCopy.iterator();
subtaskRelIterator.hasNext(); ) {
Rel subtaskRel = subtaskRelIterator.next();
if (isSubtaskLoggingOn())
logger.debug(
p(depth)
+ "OR: depth: "
+ (depth + 1)
+ " rel - "
+ subtaskRel.getParent().getFullName()
+ " : "
+ subtaskRel.getDeclaration());
if (subtaskRel.equals(subtaskRelsInPath.peekLast())
|| (!context.isRelReadyToUse(subtaskRel))
|| context.getFoundVars().containsAll(subtaskRel.getOutputs())
|| (!isSubtaskRepetitionAllowed && subtaskRelsInPath.contains(subtaskRel))) {
if (isSubtaskLoggingOn()) {
logger.debug(p(depth) + "skipped");
if (!context.isRelReadyToUse(subtaskRel)) {
logger.debug(p(depth) + "because it has unknown inputs"); // TODO print unknown
} else if (context.getFoundVars().containsAll(subtaskRel.getOutputs())) {
logger.debug(p(depth) + "because all outputs in FoundVars");
} else if (subtaskRel.equals(subtaskRelsInPath.peekLast())) {
logger.debug(p(depth) + "because it is nested in itself");
} else if (!isSubtaskRepetitionAllowed && subtaskRelsInPath.contains(subtaskRel)) {
logger.debug(
p(depth)
+ "This rel with subtasks is already in use, path: "
+ subtaskRelsInPath);
}
}
continue OR;
}
LinkedList<Rel> newPath = new LinkedList<Rel>(subtaskRelsInPath);
newPath.add(subtaskRel);
PlanningResult result = new PlanningResult(subtaskRel, true);
// this is true if all subtasks are solvable
boolean allSolved = true;
// and children
AND:
for (SubtaskRel subtask : subtaskRel.getSubtasks()) {
if (isSubtaskLoggingOn()) logger.debug(p(depth) + "AND: subtask - " + subtask);
EvaluationAlgorithm sbtAlgorithm = null;
////////////////////// INDEPENDENT SUBTASK////////////////////////////////////////
if (subtask.isIndependent()) {
if (isSubtaskLoggingOn()) logger.debug("Independent!!!");
if (subtask.isSolvable() == null) {
if (isSubtaskLoggingOn())
logger.debug("Start solving independent subtask " + subtask.getDeclaration());
// independent subtask is solved only once
Problem problemContext = subtask.getContext();
DepthFirstPlanner planner = new DepthFirstPlanner();
planner.indSubtasks = indSubtasks;
planner.nested = true;
sbtAlgorithm = planner.invokePlaning(problemContext, isOptDisabled);
PlanningContext indCntx = problemContext.getCurrentContext();
boolean solved = indCntx.getFoundVars().containsAll(indCntx.getAllGoals());
if (solved) {
subtask.setSolvable(Boolean.TRUE);
indSubtasks.put(subtask, sbtAlgorithm);
if (isSubtaskLoggingOn()) logger.debug("Solved " + subtask.getDeclaration());
} else {
subtask.setSolvable(Boolean.FALSE);
if (RuntimeProperties.isLogInfoEnabled()) {
logger.debug("Unable to solve " + subtask.getDeclaration());
}
}
allSolved &= solved;
} else if (subtask.isSolvable() == Boolean.TRUE) {
if (isSubtaskLoggingOn()) logger.debug("Already solved");
allSolved &= true;
sbtAlgorithm = indSubtasks.get(subtask);
} else {
if (isSubtaskLoggingOn()) logger.debug("Not solvable");
allSolved &= false;
}
if (isSubtaskLoggingOn()) logger.debug("End of independent subtask " + subtask);
if (!allSolved) {
continue OR;
}
assert sbtAlgorithm != null;
result.addSubtaskAlgorithm(subtask, sbtAlgorithm);
}
////////////////////// DEPENDENT SUBTASK//////////////////////////////////////
else {
// lets clone the environment
PlanningContext newContext = prepareNewContext(context, subtask);
sbtAlgorithm = new EvaluationAlgorithm();
// during linear planning, if some goals are found, they are removed from the set
// "goals"
boolean solved =
linearForwardSearch(
newContext,
sbtAlgorithm,
// do not optimize here, because the solution may require additional rels with
// subtasks
true);
if (solved) {
if (isSubtaskLoggingOn()) logger.debug(p(depth) + "SOLVED subtask: " + subtask);
if (!isOptDisabled) {
// if a subtask has been solved, optimize its algorithm
Optimizer.optimize(newContext, sbtAlgorithm);
}
result.addSubtaskAlgorithm(subtask, sbtAlgorithm);
allSolved &= solved;
continue AND;
} else if (!solved && (depth == maxDepth)) {
if (isSubtaskLoggingOn())
logger.debug(p(depth) + "NOT SOLVED and cannot go any deeper, subtask: " + subtask);
continue OR;
}
if (isSubtaskLoggingOn()) logger.debug(p(depth) + "Recursing deeper");
solved =
subtaskPlanningImpl(newContext, relsWithSubtasks, sbtAlgorithm, newPath, depth + 1);
if (isSubtaskLoggingOn()) logger.debug(p(depth) + "Back to depth " + (depth + 1));
// the linear planning has been performed at the end of MLB on the depth+1,
// if the problem was solved, there is no need to run linear planning again
if ((solved || (solved = linearForwardSearch(newContext, sbtAlgorithm, true)))
&& !isOptDisabled) {
// if solved, optimize here with full list of goals in order to get rid of
// unnecessary subtask instances and other relations
Optimizer.optimize(newContext, sbtAlgorithm);
}
if (isSubtaskLoggingOn())
logger.debug(p(depth) + (solved ? "" : "NOT") + " SOLVED subtask: " + subtask);
allSolved &= solved;
// if at least one subtask is not solvable, try another
// branch
if (!allSolved) {
continue OR;
}
result.addSubtaskAlgorithm(subtask, sbtAlgorithm);
}
} // AND
if (allSolved) {
algorithm.add(result);
Set<Var> newVars = new LinkedHashSet<Var>();
unfoldVarsToSet(subtaskRel.getOutputs(), newVars);
context.getKnownVars().addAll(newVars);
context.getFoundVars().addAll(newVars);
subtaskRelIterator.remove();
if (isSubtaskLoggingOn()) {
logger.debug(
p(depth)
+ "SOLVED ALL SUBTASKS for "
+ subtaskRel.getParent().getFullName()
+ " : "
+ subtaskRel.getDeclaration());
logger.debug(p(depth) + "Updating the problem graph and continuing building new MLB");
}
// this is used for incremental dfs
if (depth == 0) {
relsWithSubtasksToRemove.add(subtaskRel);
}
continue MLB;
}
if (isSubtaskLoggingOn())
logger.debug(
p(depth)
+ "NOT SOLVED ALL subtasks, removing from path "
+ subtaskRel.getParent().getFullName()
+ " : "
+ subtaskRel.getDeclaration());
newPath.remove(subtaskRel);
} // end OR
// exit loop because there are no more rels with subtasks to be
// applied
// (i.e. no more rels can introduce new variables into the
// algorithm)
if (isSubtaskLoggingOn()) logger.debug(p(depth) + "No more MLB can be constructed");
break MLB;
}
// incremental dfs, remove solved subtasks
if (depth == 0) {
relsWithSubtasks.removeAll(relsWithSubtasksToRemove);
}
return false;
}
private boolean subtaskPlanning(Problem problem, EvaluationAlgorithm algorithm) {
if (isSubtaskLoggingOn())
logger.debug("!!!--------- Starting Planning With Subtasks ---------!!!");
final int maxDepthBackup = maxDepth;
if (isSubtaskLoggingOn())
logger.debug(
"maxDepthBackup:" + maxDepthBackup + " sbt: " + problem.getRelsWithSubtasks().size());
PlanningContext context = problem.getCurrentContext();
try {
Set<Rel> relsWithSubtasks = new LinkedHashSet<Rel>(problem.getRelsWithSubtasks());
if (isIncremental) {
int incrementalDepth = 0;
while (incrementalDepth
<= (isSubtaskRepetitionAllowed
? maxDepthBackup
: problem.getRelsWithSubtasks().size() - 1)) {
if (isSubtaskLoggingOn())
logger.debug(
"Incremental dfs, with max depth "
+ (incrementalDepth + 1)
+ " and "
+ problem.getRelsWithSubtasks().size()
+ " subtasks to solve");
maxDepth = incrementalDepth++;
// if we need to compute some specific goals, after reaching a certain depth, but not the
// maximal depth,
// the problem may be solved and there is no need to go any deeper.
if (subtaskPlanningImpl(context, relsWithSubtasks, algorithm, new LinkedList<Rel>(), 0)) {
if (isSubtaskLoggingOn())
logger.debug("The problem was solved during idfs after some intermediate MLB");
return true;
}
if (isSubtaskLoggingOn())
logger.debug("Unsolved subtask left: " + problem.getRelsWithSubtasks().size());
}
if (isSubtaskLoggingOn()) logger.debug("Fininshed incremental dfs");
} else {
if (!isSubtaskRepetitionAllowed) {
maxDepth = problem.getRelsWithSubtasks().size() - 1;
}
if (isSubtaskLoggingOn())
logger.debug("Starting subtask dfs with maxDepth: " + (maxDepth + 1));
if (subtaskPlanningImpl(context, relsWithSubtasks, algorithm, new LinkedList<Rel>(), 0)) {
if (isSubtaskLoggingOn())
logger.debug("The problem was solved during dfs after some intermediate MLB");
return true;
}
}
} finally {
if (isSubtaskLoggingOn()) logger.debug("Fininshed dfs");
maxDepth = maxDepthBackup;
indSubtasks.clear();
}
if (isSubtaskLoggingOn()) logger.debug("Invoking final linear planning");
return linearForwardSearch(context, algorithm, computeAll);
}