Example #1
0
  /**
   * This method is the access point to the planning procedure. Initially, it adds all variables
   * from axioms to the set of found vars, then does the linear planning. If lp does not solve the
   * problem and there are subtasks, goal-driven recursive planning with backtracking is invoked.
   * Planning is performed until no new variables are introduced into the algorithm.
   */
  public EvaluationAlgorithm invokePlaning(Problem problem, boolean _computeAll) {
    long startTime = System.currentTimeMillis();

    computeAll = _computeAll;
    EvaluationAlgorithm algorithm = new EvaluationAlgorithm();

    PlanningContext context = problem.getCurrentContext();

    // add all axioms at the beginning of an algorithm
    Collection<Var> flattened = new HashSet<Var>();
    for (Iterator<Rel> axiomIter = problem.getAxioms().iterator(); axiomIter.hasNext(); ) {
      Rel rel = axiomIter.next();

      unfoldVarsToSet(rel.getOutputs(), flattened);

      // do not overwrite values of variables that come via args of compute() or as inputs of
      // independent subtasks
      if (!problem.getAssumptions().containsAll(flattened)
      // do not overwrite values of already known variables.
      // typically this is the case when a value of a variable
      // is given in a scheme via a properties window
      //                    && !problem.getKnownVars().containsAll( flattened )
      ) {
        algorithm.addRel(rel);
      }
      axiomIter.remove();
      context.getKnownVars().addAll(flattened);
      flattened.clear();
    }

    context.getFoundVars().addAll(context.getKnownVars());

    // remove all known vars with no relations
    for (Iterator<Var> varIter = context.getKnownVars().iterator(); varIter.hasNext(); ) {
      if (varIter.next().getRels().isEmpty()) {
        varIter.remove();
      }
    }

    // start planning
    if (problem.getRelsWithSubtasks().isEmpty()
        && linearForwardSearch(context, algorithm, computeAll)) {
      if (isLinearLoggingOn()) logger.debug("Problem solved without subtasks");
    } else if (!problem.getRelsWithSubtasks().isEmpty() && subtaskPlanning(problem, algorithm)) {
      if (isLinearLoggingOn()) logger.debug("Problem solved with subtasks");
    } else if (!computeAll) {
      if (isLinearLoggingOn()) logger.debug("Problem not solved");
    }

    if (!nested) {
      logger.info("Planning time: " + (System.currentTimeMillis() - startTime) + "ms.");
    }
    return algorithm;
  }
Example #2
0
  private PlanningContext prepareNewContext(PlanningContext context, Rel subtask) {

    PlanningContext newContext = context.getCopy();
    // [x->y] assume x is known
    Set<Var> allSubtaskInputs = new LinkedHashSet<Var>();
    unfoldVarsToSet(subtask.getInputs(), allSubtaskInputs);
    newContext.getKnownVars().addAll(allSubtaskInputs);
    newContext.getFoundVars().addAll(allSubtaskInputs);
    Set<Var> goals = new LinkedHashSet<Var>();
    unfoldVarsToSet(subtask.getOutputs(), goals);
    newContext.addGoals(goals);
    return newContext;
  }
Example #3
0
  /**
   * 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;
  }
Example #4
0
  /**
   * Linear forward search algorithm
   *
   * @param p
   * @param algorithm
   * @param targetVars
   * @param _computeAll
   * @return
   */
  private boolean linearForwardSearch(
      PlanningContext context, EvaluationAlgorithm algorithm, boolean _computeAll) {

    /*
     * while iterating through hashset, items cant be removed from/added to
     * that set. Theyre collected into these sets and added/removedall
     * together after iteration is finished
     */
    Set<Var> newVars = new LinkedHashSet<Var>();
    Set<Var> relOutputs = new LinkedHashSet<Var>();
    Set<Var> removableVars = new LinkedHashSet<Var>();

    boolean changed = true;

    if (isLinearLoggingOn())
      logger.debug(
          "------Starting linear planning with (sub)goals: "
              + context.getRemainingGoals()
              + "--------");

    if (isLinearLoggingOn()) logger.debug("Algorithm " + algorithm);

    int counter = 1;

    while ((!_computeAll && changed && !context.getRemainingGoals().isEmpty())
        || (changed && _computeAll)) {

      if (isLinearLoggingOn()) logger.debug("----Iteration " + counter + " ----");

      counter++;
      changed = false;

      // iterate through all knownvars
      if (isLinearLoggingOn()) logger.debug("Known:" + context.getKnownVars());

      for (Var var : context.getKnownVars()) {

        if (isLinearLoggingOn()) logger.debug("Current Known: " + var);

        // Check the relations of all components
        for (Rel rel : var.getRels()) {
          if (isLinearLoggingOn()) logger.debug("And its rel: " + rel);
          if (context.isAvailableRel(rel)) {
            context.removeUnknownInput(rel, var);

            if (isLinearLoggingOn()) logger.debug("problem contains it " + rel);

            removableVars.add(var);

            if (context.isRelReadyToUse(rel) && rel.getType() != RelType.TYPE_METHOD_WITH_SUBTASK) {

              if (isLinearLoggingOn()) logger.debug("rel is ready to be used " + rel);

              boolean relIsNeeded = false;

              if (isLinearLoggingOn()) logger.debug("its outputs " + rel.getOutputs());

              for (Var relVar : rel.getOutputs()) {

                if (!context.getFoundVars().contains(relVar)) {
                  relIsNeeded = true;
                }
              }

              if (rel.getOutputs().isEmpty()) {
                relIsNeeded = true;
              }
              if (isLinearLoggingOn()) logger.debug("relIsNeeded " + relIsNeeded);

              if (relIsNeeded) {

                if (isLinearLoggingOn()) logger.debug("needed rel:  " + rel);

                if (!rel.getOutputs().isEmpty()) {
                  relOutputs.clear();
                  unfoldVarsToSet(rel.getOutputs(), relOutputs);
                  newVars.addAll(relOutputs);
                  context.getFoundVars().addAll(relOutputs);
                }
                algorithm.addRel(rel);
                if (isLinearLoggingOn()) logger.debug("algorithm " + algorithm);
              }

              context.removeRel(rel);
              changed = true;
            }
          }
        }
      }

      // remove targets if they have already been found
      for (Iterator<Var> targetIter = context.getRemainingGoals().iterator();
          targetIter.hasNext(); ) {
        Var targetVar = targetIter.next();
        if (context.getFoundVars().contains(targetVar)) {
          targetIter.remove();
        }
      }

      if (isLinearLoggingOn()) logger.debug("foundvars " + context.getFoundVars());

      context.getKnownVars().addAll(newVars);
      context.getKnownVars().removeAll(removableVars);
      newVars.clear();
    }
    if (isLinearLoggingOn()) logger.debug("algorithm " + algorithm);

    if (!_computeAll) {
      Optimizer.optimize(context, algorithm);

      if (isLinearLoggingOn()) logger.debug("optimized algorithm " + algorithm);
    }

    if (isLinearLoggingOn()) logger.debug("\n---!!!Finished linear planning!!!---\n");

    return context.getRemainingGoals().isEmpty()
        || context.getFoundVars().containsAll(context.getAllGoals());
  }