/// <summary>
/// Extracts a minimal necessary operator substitution needed for the backward application (other parameters remain lifted).
/// </summary>
/// <returns>Minimal substitution.</returns>
public ISubstitution ExtractMinimalOperatorSubstitution()
{
// we need to determine, which effects were actually used for the backwards application (i.e. have to be grounded).
ISubstitution substitution = new Substitution();
foreach (var predicate in UsedGroundedPredicates)
{
IAtom liftedPredicate;
if (Effects.OriginalLiftedPredicates.TryGetValue(predicate, out liftedPredicate))
{
var unification = liftedPredicate.GetUnificationWith(predicate);
substitution.AddLocalSubstitution(unification);
}
}
foreach (var function in UsedGroundedFunctions)
{
IAtom liftedFunction;
if (Effects.OriginalLiftedFunctions.TryGetValue(function, out liftedFunction))
{
var unification = liftedFunction.GetUnificationWith(function);
substitution.AddLocalSubstitution(unification);
}
}
return(substitution);
}
/// <summary>
/// Visits and performs a property count on forall expression.
/// </summary>
/// <param name="expression">Forall expression.</param>
/// <returns>Tuple (property satisfied count, property not satisfied count).</returns>
public Tuple <double, double> Visit(ForallExpression expression)
{
double positiveValue = 0;
double negativeValue = 0;
IEnumerable <ISubstitution> localSubstitutions = GroundingManager.GenerateAllLocalSubstitutions(expression.Parameters);
foreach (var localSubstitution in localSubstitutions)
{
Substitution.AddLocalSubstitution(localSubstitution);
var childPropertyCounts = expression.Child.Accept(this);
Substitution.RemoveLocalSubstitution(localSubstitution);
if (EvaluationStrategy == ForwardCostEvaluationStrategy.ADDITIVE_VALUE)
{
positiveValue += childPropertyCounts.Item1;
negativeValue += childPropertyCounts.Item2;
}
else
{
positiveValue = Math.Max(positiveValue, childPropertyCounts.Item1);
negativeValue = Math.Max(negativeValue, childPropertyCounts.Item2);
}
}
return(Tuple.Create(positiveValue, negativeValue));
}
/// <summary>
/// Visits and handles the effect.
/// </summary>
/// <param name="effect">Effect.</param>
public void Visit(ForallEffect effect)
{
IEnumerable <ISubstitution> localSubstitutions = GroundingManager.GenerateAllLocalSubstitutions(effect.Parameters);
foreach (var localSubstitution in localSubstitutions)
{
Substitution.AddLocalSubstitution(localSubstitution);
foreach (var localEffect in effect.Effects)
{
localEffect.Accept(this);
}
Substitution.RemoveLocalSubstitution(localSubstitution);
}
}
/// <summary>
/// Visits and evaluates forall expression.
/// </summary>
/// <param name="expression">Forall expression.</param>
/// <returns>True if the specified expression evaluates as true, false otherwise.</returns>
public bool Visit(ForallExpression expression)
{
IEnumerable <ISubstitution> localSubstitutions = GroundingManager.GenerateAllLocalSubstitutions(expression.Parameters);
foreach (var localSubstitution in localSubstitutions)
{
Substitution.AddLocalSubstitution(localSubstitution);
bool subExpressionResult = expression.Child.Accept(this);
Substitution.RemoveLocalSubstitution(localSubstitution);
if (!subExpressionResult)
{
return(false);
}
}
return(true);
}
/// <summary>
/// Visits and performs a property count on exists expression.
/// </summary>
/// <param name="expression">Exists expression.</param>
/// <returns>Tuple (property satisfied count, property not satisfied count).</returns>
public Tuple <double, double> Visit(ExistsExpression expression)
{
double positiveValue = 0.0;
double negativeValue = 0.0;
IEnumerable <ISubstitution> localSubstitutions = GroundingManager.GenerateAllLocalSubstitutions(expression.Parameters);
foreach (var localSubstitution in localSubstitutions)
{
Substitution.AddLocalSubstitution(localSubstitution);
var childPropertyCounts = expression.Child.Accept(this);
Substitution.RemoveLocalSubstitution(localSubstitution);
positiveValue = Math.Max(positiveValue, childPropertyCounts.Item1);
negativeValue = Math.Max(negativeValue, childPropertyCounts.Item2);
}
return(Tuple.Create(positiveValue, negativeValue));
}
/// <summary>
/// Visits and performs a property count on forall expression.
/// </summary>
/// <param name="expression">Forall expression.</param>
/// <returns>Tuple (property satisfied count, property not satisfied count).</returns>
public Tuple <int, int> Visit(ForallExpression expression)
{
int fulfilled = 0;
int notFulfilled = 0;
IEnumerable <ISubstitution> localSubstitutions = GroundingManager.GenerateAllLocalSubstitutions(expression.Parameters);
foreach (var localSubstitution in localSubstitutions)
{
Substitution.AddLocalSubstitution(localSubstitution);
var childPropertyCounts = expression.Child.Accept(this);
Substitution.RemoveLocalSubstitution(localSubstitution);
fulfilled += childPropertyCounts.Item1;
notFulfilled += childPropertyCounts.Item2;
}
return(Tuple.Create(fulfilled, notFulfilled));
}
/// <summary>
/// Visits and performs a property count on exists expression.
/// </summary>
/// <param name="expression">Exists expression.</param>
/// <returns>Tuple (property satisfied count, property not satisfied count).</returns>
public Tuple <int, int> Visit(ExistsExpression expression)
{
int minFulfilled = int.MaxValue;
int minNotFulfilled = int.MaxValue;
IEnumerable <ISubstitution> localSubstitutions = GroundingManager.GenerateAllLocalSubstitutions(expression.Parameters);
foreach (var localSubstitution in localSubstitutions)
{
Substitution.AddLocalSubstitution(localSubstitution);
var childPropertyCounts = expression.Child.Accept(this);
Substitution.RemoveLocalSubstitution(localSubstitution);
minFulfilled = Math.Min(minFulfilled, childPropertyCounts.Item1);
minNotFulfilled = Math.Min(minNotFulfilled, childPropertyCounts.Item2);
}
return(Tuple.Create(minFulfilled, minNotFulfilled));
}
