private static void ConstructVariableList(ExpressionInteger expression, ISet <IVariable <int> > variableSet)
{
if (expression.Left is VariableInteger)
{
variableSet.Add((VariableInteger)expression.Left);
}
else if (expression.Left is ExpressionInteger)
{
ConstructVariableList((ExpressionInteger)expression.Left, variableSet);
}
if (expression.Right is VariableInteger)
{
variableSet.Add((VariableInteger)expression.Right);
}
else if (expression.Right is ExpressionInteger)
{
ConstructVariableList((ExpressionInteger)expression.Right, variableSet);
}
}
private static void ConstructVariableList(ExpressionInteger expression, ISet <IVariable <int> > variableSet)
{
if (expression.Left is VariableInteger)
{
variableSet.Add((VariableInteger)expression.Left);
}
else if (expression.Left is MetaExpressionInteger)
{
ConstructVariableList((ExpressionInteger)expression.Left, variableSet);
foreach (var variable in ((IMetaExpression <int>)expression.Left).Support)
{
variableSet.Add(variable);
}
}
else if (expression.Left is ExpressionInteger)
{
ConstructVariableList((ExpressionInteger)expression.Left, variableSet);
}
if (expression.Right is VariableInteger)
{
variableSet.Add((VariableInteger)expression.Right);
}
else if (expression.Right is MetaExpressionInteger)
{
ConstructVariableList((ExpressionInteger)expression.Right, variableSet);
foreach (var variable in ((IMetaExpression <int>)expression.Right).Support)
{
variableSet.Add(variable);
}
}
else if (expression.Right is ExpressionInteger)
{
ConstructVariableList((ExpressionInteger)expression.Right, variableSet);
}
}
public static ExpressionInteger operator -(ExpressionInteger left, ExpressionInteger right)
{
var expression = new ExpressionInteger(left, right)
{
evaluate = (l, r) => l.Value - r.Value,
evaluateBounds = (l, r) =>
{
var leftBounds = l.GetUpdatedBounds();
var rightBounds = r.GetUpdatedBounds();
return(new Bounds <int>
(
leftBounds.LowerBound - rightBounds.UpperBound,
leftBounds.UpperBound - rightBounds.LowerBound
));
},
propagator = (first, second, enforce) =>
{
var result = ConstraintOperationResult.Undecided;
if (first.Bounds.LowerBound < enforce.LowerBound + second.Bounds.LowerBound)
{
first.Bounds.LowerBound = enforce.LowerBound + second.Bounds.LowerBound;
result = ConstraintOperationResult.Propagated;
}
if (first.Bounds.UpperBound > enforce.UpperBound + second.Bounds.UpperBound)
{
first.Bounds.UpperBound = enforce.UpperBound + second.Bounds.UpperBound;
result = ConstraintOperationResult.Propagated;
}
if (second.Bounds.LowerBound < first.Bounds.LowerBound - enforce.UpperBound)
{
second.Bounds.LowerBound = first.Bounds.LowerBound - enforce.UpperBound;
result = ConstraintOperationResult.Propagated;
}
if (second.Bounds.UpperBound > first.Bounds.UpperBound - enforce.LowerBound)
{
second.Bounds.UpperBound = first.Bounds.UpperBound - enforce.LowerBound;
result = ConstraintOperationResult.Propagated;
}
if (first.Bounds.LowerBound > first.Bounds.UpperBound || second.Bounds.LowerBound > second.Bounds.UpperBound)
{
result = ConstraintOperationResult.Violated;
}
return(result);
}
};
expression.remove = prune =>
{
var result = DomainOperationResult.ElementNotInDomain;
if (expression.left.Bounds.UpperBound - expression.left.Bounds.LowerBound == 0)
{
result = ((ExpressionInteger)expression.right).remove(expression.left.Bounds.LowerBound - prune);
}
if (result == DomainOperationResult.EmptyDomain)
{
return(result);
}
if (expression.right.Bounds.UpperBound - expression.right.Bounds.LowerBound == 0)
{
result = ((ExpressionInteger)expression.left).remove(expression.right.Bounds.LowerBound + prune);
}
return(result);
};
return(expression);
}
