edu.cmu.cs.coral.icf.plan_based.planners.pip
Class PIPPlanGenerator

java.lang.Object
  |
  +--edu.cmu.cs.coral.icf.plan_based.planners.pip.PIPPlanGenerator

public class PIPPlanGenerator

extends java.lang.Object

Generates plan for the Prodigy Inspired Planner (PIP). This class implements the guts of the algrithm

Since:

ICF 0.0

Version:

$Id$

Field Summary

private java.util.Stack	backtrackPoints the decisions that have been made so far (used for backtracking)
private Choice	lastChoice the last choice that was made
private PIPPlan	plan the current plan

Constructor Summary

PIPPlanGenerator()
Construct a PIPPlanGenerator

Method Summary

private java.util.Iterator	genChoices() Generates the choices that can be used for the next decision.
private void	preprocess(PlannerDomain domain, PlannerProblem problem) Preprocess the domain and problem to be used by the planning algorithm
private PIPPlan	search(PlannerDomain domain, PlannerProblem problem) Finds a plan that solves the problem if one exists
PIPPlan	solve(PlannerDomain domain, PlannerProblem problem) Solve a planning problem.
private boolean	tryBindingSelection(OpNodeExpansionChoice op_choice, BindingSelectionChoice binding_choice, ChangeTracker change_tracker) Tries to expand the op node chosen with the variable binding chosen.
private boolean	tryChoice(Choice choice, ChangeTracker change_tracker) Tries to execute the choice that was made.
private boolean	tryGoalNodeExpansion(GoalNodeExpansionChoice choice, ChangeTracker change_tracker) Tries to expand the given goal node.
private boolean	tryNextAlternative(Decision decision) Tries the next altenative remaining at this decision point.
private boolean	tryOpApplication(OpApplicationChoice choice, ChangeTracker change_tracker) Tries to apply the operator specified by this choice.
private boolean	tryOpNodeExpansion(OpNodeExpansionChoice choice, ChangeTracker change_tracker) Tries to expand the given op node.
private boolean	tryOpSelection(GoalNodeExpansionChoice goal_choice, OperatorSelectionChoice op_choice, ChangeTracker change_tracker) Tries to expand the goal node chosen with the operator chosen.

Methods inherited from class java.lang.Object

, clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait

Field Detail

backtrackPoints

private java.util.Stack backtrackPoints

the decisions that have been made so far (used for backtracking)

Since:

ICF 0.0

plan

private PIPPlan plan

the current plan

Since:

ICF 0.0

lastChoice

private Choice lastChoice

the last choice that was made

Since:

ICF 0.0

Constructor Detail

PIPPlanGenerator

public PIPPlanGenerator()

Construct a PIPPlanGenerator

Since:

ICF 0.0

Method Detail

solve

public PIPPlan solve(PlannerDomain domain,
                     PlannerProblem problem)

Solve a planning problem.

Parameters:

domain - the domain to use

problem - the problem to solve

Returns:

a plan that solves the problem or null if no such plan exists

Since:

ICF 0.0

preprocess

private void preprocess(PlannerDomain domain,
                        PlannerProblem problem)

Preprocess the domain and problem to be used by the planning algorithm

Parameters:

domain - the domain to use

problem - the problem to use

Since:

ICF 0.0

search

private PIPPlan search(PlannerDomain domain,
                       PlannerProblem problem)

Finds a plan that solves the problem if one exists

Parameters:

domain - the domain to use

problem - the problem to use

Returns:

a plan that solves the problem or null if no such plan exists

Since:

ICF 0.0

genChoices

private java.util.Iterator genChoices()

Generates the choices that can be used for the next decision.

Returns:

an iterator over the possible choice for the next decision

Since:

ICF 0.0

tryNextAlternative

private boolean tryNextAlternative(Decision decision)

Tries the next altenative remaining at this decision point.

Parameters:

decision - the decision point to try the next alternative for

Returns:

true if and only if a valid alternative was found and executed

Since:

ICF 0.0

tryChoice

private boolean tryChoice(Choice choice,
                          ChangeTracker change_tracker)

Tries to execute the choice that was made.

Parameters:

choice - the option to try

change_tracker - the change tracker to track changes to the plan with

Returns:

true if and only if the choice was successfully done

Since:

ICF 0.0

tryOpApplication

private boolean tryOpApplication(OpApplicationChoice choice,
                                 ChangeTracker change_tracker)

Tries to apply the operator specified by this choice.

Parameters:

choice - the op application choice made

change_tracker - the change tracker to track changes to the plan with

Returns:

true if and only if this operator was successfuly applied

Since:

ICF 0.0

tryGoalNodeExpansion

private boolean tryGoalNodeExpansion(GoalNodeExpansionChoice choice,
                                     ChangeTracker change_tracker)

Tries to expand the given goal node. This merely indicated that this node should be expanded and doesn't actually do the expansion.

Parameters:

choice - the goal node chosen to be expanded

change_tracker - the change tracker to track changes to the plan with

Returns:

true if and only if this node was successfully marked for expansion

Since:

ICF 0.0

tryOpNodeExpansion

private boolean tryOpNodeExpansion(OpNodeExpansionChoice choice,
                                   ChangeTracker change_tracker)

Tries to expand the given op node. This merely indicated that this node should be expanded and doesn't actually do the expansion.

Parameters:

choice - the op node chosen to be expanded

change_tracker - the change tracker to track changes to the plan with

Returns:

true if and only if this node was successfully marked for expansion

Since:

ICF 0.0

tryOpSelection

private boolean tryOpSelection(GoalNodeExpansionChoice goal_choice,
                               OperatorSelectionChoice op_choice,
                               ChangeTracker change_tracker)

Tries to expand the goal node chosen with the operator chosen.

Parameters:

goal_choice - the choice of goal node

op_choice - the choice of operator

change_tracker - the change tracker to track changes to the plan with

Returns:

true if and only if the expansion was successfully carried out

Since:

ICF 0.0

tryBindingSelection

private boolean tryBindingSelection(OpNodeExpansionChoice op_choice,
                                    BindingSelectionChoice binding_choice,
                                    ChangeTracker change_tracker)

Tries to expand the op node chosen with the variable binding chosen.

Parameters:

op_choice - the operator chosen for expansion

binding_choice - the binding chosen

change_tracker - the change tracker to track changes to the plan with

Returns:

true if and only if the binding was successful

Since:

ICF 0.0