Package fr.uga.pddl4j.heuristics.state

Class SetLevel

java.lang.Object

fr.uga.pddl4j.heuristics.AbstractHeuristic

fr.uga.pddl4j.heuristics.state.AbstractStateHeuristic

fr.uga.pddl4j.heuristics.state.GraphHeuristic

fr.uga.pddl4j.heuristics.state.SetLevel

All Implemented Interfaces:

Heuristic, PlanningGraphHeuristic, StateHeuristic, Serializable

public final class SetLevel
extends GraphHeuristic

This heuristic returns the level of the planning graph where all the propositions of the goal are reached without any mutex free. For more information on this heuristic see: X. Nguyen and S. Kambhampati. "Extracting effective and admissible state space heuristics from the planning graph". In proceedings of the National Conference on Innovative Applications of Artificial Intelligence, 2000. Warning: The set-level heuristic is admissible.

See Also:

RelaxedGraphHeuristic, Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface fr.uga.pddl4j.heuristics.state.StateHeuristic

StateHeuristic.Name

Constructor Summary

Constructors

Constructor	Description
SetLevel(Problem problem)	Creates a new SET_LEVEL heuristic for a specified planning problem.

Method Summary

Modifier and Type	Method	Description
double	estimate(Node node, Condition goal)	Return the estimated distance to the goal to reach the specified state.
int	estimate(State state, Condition goal)	Return the distance to the goal state from the specified state.

Methods inherited from class fr.uga.pddl4j.heuristics.state.GraphHeuristic

expandPlanningGraph, getSumValue, isGoalReachable, setGoal

Methods inherited from class fr.uga.pddl4j.heuristics.state.AbstractStateHeuristic

getActions, getGoal, getRevelantFacts, isAdmissible, setAdmissible

Methods inherited from class java.lang.Object

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

Methods inherited from interface fr.uga.pddl4j.heuristics.state.StateHeuristic

isAdmissible

Constructor Details

SetLevel

public SetLevel(Problem problem)

Creates a new SET_LEVEL heuristic for a specified planning problem.

Parameters:

problem - the planning problem.

Throws:

NullPointerException - if problem == null.

Method Details

estimate

public int estimate(State state,
 Condition goal)

Return the distance to the goal state from the specified state. If the return value is Integer.MAX_VALUE, it means that the goal is unreachable from the specified state. More precisely, this method returns the level of the planning graph where all the propositions of the goal are reached without any mutex or Integer.MAX_VALUE otherwise.

Parameters:

state - the state from which the distance to the goal must be estimated.

goal - the goal expression.

Returns:

the distance to the goal state from the specified state or Integer.MAX_VALUE if the goal is unreachable from the specified state.

estimate

public double estimate(Node node,
 Condition goal)

Return the estimated distance to the goal to reach the specified state. If the return value is DOUBLE.MAX_VALUE, it means that the goal is unreachable from the specified state.

Parameters:

node - the state from which the distance to the goal must be estimated.

goal - the goal expression.

Returns:

the distance to the goal state from the specified state.