Package fr.uga.pddl4j.heuristics.state

Class Combo

java.lang.Object

fr.uga.pddl4j.heuristics.AbstractHeuristic

fr.uga.pddl4j.heuristics.state.AbstractStateHeuristic

fr.uga.pddl4j.heuristics.state.RelaxedGraphHeuristic

fr.uga.pddl4j.heuristics.state.Combo

All Implemented Interfaces:

Heuristic, PlanningGraphHeuristic, StateHeuristic, Serializable

public final class Combo
extends RelaxedGraphHeuristic

This class implement the combo heuristic. This heuristic improves the adjusted sum heuristic by replacing the computation of the interaction degree of the adjusted sum heuristic. Now, we have the following heuristic:

 combo(S) := hsum(S) + hlvel(S)
 

where

• hsum(S) is the sum heuristic value and
• hlev(S) the set-level heuristic value.

Warning: The combo heuristic is not admissible.

See Also:

AdjustedSum, Sum, SetLevel, Serialized Form

Nested Class Summary

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

StateHeuristic.Name

Constructor Summary

Constructors

Constructor	Description
Combo(Problem problem)	Creates a new COMBO 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 estimated distance to the goal to reach the specified state.

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

expandRelaxedPlanningGraph, getMaxValue, getRelaxedPlanValue, 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

Combo

public Combo(Problem problem)

Creates a new COMBO 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 estimated distance to the goal to reach the specified state. If the return value is Integer.MAX_VALUE, it means that the goal is unreachable from the specified state.

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.

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.