/// <summary>
/// Computes the forward cost heuristics for the given state in the relaxed planning graph.
/// </summary>
/// <param name="state">Starting state.</param>
/// <param name="goalConditions">Goal conditions.</param>
/// <param name="evaluationStrategy">Evaluation strategy.</param>
/// <returns>Forward cost heuristic value from the specified state.</returns>
private double ComputeForwardCost(IState state, IConditions goalConditions, ForwardCostEvaluationStrategy evaluationStrategy)
{
IStateLayer previousStateLayer = null;
IStateLayer stateLayer = CreateLabeledStateLayer(state.GetRelaxedState());
ActionLayer actionLayer = new ActionLayer();
while (!stateLayer.Equals(previousStateLayer))
{
// check goal conditions
if (goalConditions.Evaluate(stateLayer.GetState()))
{
return(goalConditions.EvaluateOperatorPlanningGraphLabel(stateLayer.GetStateLabels(), evaluationStrategy));
}
// build new action layer
actionLayer.Clear();
foreach (var successor in RelaxedProblem.GetSuccessors(stateLayer.GetState()))
{
IOperator appliedOperator = successor.GetAppliedOperator();
double label = appliedOperator.ComputePlanningGraphLabel(stateLayer.GetStateLabels(), evaluationStrategy);
actionLayer.Add(new ActionNode(appliedOperator, label + appliedOperator.GetCost()));
}
// build new state layer
previousStateLayer = stateLayer;
stateLayer = CreateLabeledStateLayer(stateLayer, actionLayer);
}
// failure, solution cannot be found from the specified state
return(int.MaxValue);
}
/// <summary>
/// Evaluates the label of the operator with the specified preconditions and substitution.
/// </summary>
/// <param name="conditions">Operator conditions.</param>
/// <param name="substitution">Variable substitution.</param>
/// <param name="stateLabels">Atom labels in the predecessor layer.</param>
/// <param name="evaluationStrategy">Evaluation strategy.</param>
/// <returns>Operator label value in the relaxed planning graph.</returns>
public double Evaluate(ConditionsCNF conditions, ISubstitution substitution, StateLabels stateLabels, ForwardCostEvaluationStrategy evaluationStrategy)
{
Substitution = substitution;
StateLabels = stateLabels;
EvaluationStrategy = evaluationStrategy;
return(conditions.Accept(this).Item1);
}
/// <summary>
/// Computes the operator label in the relaxed planning graph.
/// </summary>
/// <param name="stateLabels">State labels from the predecessor layer in the graph.</param>
/// <param name="evaluationStrategy">Evaluation strategy of the planning graph.</param>
/// <returns>Computed operator label in the relaxed planning graph.</returns>
public double EvaluateOperatorPlanningGraphLabel(IStateLabels stateLabels, ForwardCostEvaluationStrategy evaluationStrategy)
{
double result = 0;
foreach (var conditions in this)
{
result = Math.Max(result, conditions.EvaluateOperatorPlanningGraphLabel(stateLabels, evaluationStrategy));
}
return(result);
}
/// <summary>
/// Computes the operator label in the relaxed planning graph.
/// </summary>
/// <param name="stateLabels">State labels from the predecessor layer in the graph.</param>
/// <param name="evaluationStrategy">Evaluation strategy of the planning graph.</param>
/// <returns>Computed operator label in the relaxed planning graph.</returns>
public double EvaluateOperatorPlanningGraphLabel(IStateLabels stateLabels, ForwardCostEvaluationStrategy evaluationStrategy)
{
StateLabels labels = (StateLabels)stateLabels;
double result = 0;
foreach (var assignment in this)
{
double variableLabel = labels[assignment];
if (evaluationStrategy == ForwardCostEvaluationStrategy.ADDITIVE_VALUE)
{
result += variableLabel;
}
else
{
result = Math.Max(result, variableLabel);
}
}
return(result);
}
/// <summary>
/// Computes the operator label in the relaxed planning graph.
/// </summary>
/// <param name="substitution">Variable substitution.</param>
/// <param name="stateLabels">Atom labels from the predecessor layer in the graph.</param>
/// <param name="evaluationStrategy">Evaluation strategy of the planning graph.</param>
/// <returns>Computed operator label in the relaxed planning graph.</returns>
public double EvaluateOperatorPlanningGraphLabel(ISubstitution substitution, IStateLabels stateLabels, ForwardCostEvaluationStrategy evaluationStrategy)
{
return(EvaluationManager.EvaluateOperatorPlanningGraphLabel(this, substitution, (StateLabels)stateLabels, evaluationStrategy));
}
/// <summary>
/// Computes the operator label in the relaxed planning graph.
/// </summary>
/// <param name="stateLabels">State labels from the predecessor layer in the graph.</param>
/// <param name="evaluationStrategy">Evaluation strategy of the planning graph.</param>
/// <returns>Computed operator label in the relaxed planning graph.</returns>
public double EvaluateOperatorPlanningGraphLabel(IStateLabels stateLabels, ForwardCostEvaluationStrategy evaluationStrategy)
{
return(EvaluateOperatorPlanningGraphLabel(null, stateLabels, evaluationStrategy));
}
/// <summary>
/// Computes the operator label in the relaxed planning graph.
/// </summary>
/// <param name="stateLabels">State labels from the predecessor layer in the graph.</param>
/// <param name="evaluationStrategy">Evaluation strategy of the planning graph.</param>
/// <returns>Computed operator label in the relaxed planning graph.</returns>
public double EvaluateOperatorPlanningGraphLabel(IStateLabels stateLabels, ForwardCostEvaluationStrategy evaluationStrategy)
{
return(int.MaxValue);
}
/// <summary>
/// Computes the operator label in the relaxed planning graph.
/// </summary>
/// <param name="substitution">Variable substitution.</param>
/// <param name="stateLabels">Atom labels from the predecessor layer in the graph.</param>
/// <param name="evaluationStrategy">Evaluation strategy of the planning graph.</param>
/// <returns>Computed operator label in the relaxed planning graph.</returns>
public double ComputePlanningGraphLabel(ISubstitution substitution, StateLabels stateLabels, ForwardCostEvaluationStrategy evaluationStrategy)
{
return(Preconditions.EvaluateOperatorPlanningGraphLabel(substitution, stateLabels, evaluationStrategy));
}
/// <summary>
/// Computes the operator label in the relaxed planning graph.
/// </summary>
/// <param name="conditions">Operator preconditions.</param>
/// <param name="substitution">Variable substitution.</param>
/// <param name="stateLabels">Atom labels from the predecessor layer in the graph.</param>
/// <param name="evaluationStrategy">Evaluation strategy of the planning graph.</param>
/// <returns>Computed operator label in the relaxed planning graph.</returns>
public double EvaluateOperatorPlanningGraphLabel(ConditionsCNF conditions, ISubstitution substitution, StateLabels stateLabels, ForwardCostEvaluationStrategy evaluationStrategy)
{
return(PlanningGraphOperatorLabelEvaluatorCNF.Value.Evaluate(conditions, substitution, stateLabels, evaluationStrategy));
}
/// <summary>
/// Computes the operator label in the relaxed planning graph.
/// </summary>
/// <param name="stateLabels">Atom labels from the predecessor layer in the graph.</param>
/// <param name="evaluationStrategy">Evaluation strategy of the planning graph.</param>
/// <returns>Computed operator label in the relaxed planning graph.</returns>
public double ComputePlanningGraphLabel(IStateLabels stateLabels, ForwardCostEvaluationStrategy evaluationStrategy)
{
return(LiftedOperator.ComputePlanningGraphLabel(Substitution, (StateLabels)stateLabels, evaluationStrategy));
}
