private bool ReviseLeft(VariableNode leftNode, VariableNode rightNode, BinaryConstraintExpression expression)
{
var leftDomainRange = leftNode.Variable.Domain;
IReadOnlyCollection <int> rightPossibleValues;
if (!expression.Node.InnerExpression.RightExpression.IsLiteral)
{
rightPossibleValues = rightNode.Variable.Domain.PossibleValues;
}
else
{
var lhsVariable = _modelSolverMap.GetModelVariableByName(leftNode.Variable.Name);
var range = _valueMapper.GetDomainValueFor(lhsVariable);
var modelValue = expression.Node.InnerExpression.RightExpression.GetLiteral();
var solverValue = range.MapTo(modelValue);
rightPossibleValues = new ReadOnlyCollection <int>(new List <int> {
solverValue
});
}
var valueEvaluator = new LeftValueEvaluator(rightPossibleValues, expression);
var valuesToRemove = new List <int>();
var expressionEvaluator = new ExpressionEvaluator();
foreach (var possibleValue in leftDomainRange.PossibleValues)
{
var evaluatedPossibleValue = expressionEvaluator.Evaluate(expression.Node.InnerExpression.LeftExpression, possibleValue);
if (!valueEvaluator.EvaluateLeft(evaluatedPossibleValue))
{
valuesToRemove.Add(possibleValue);
}
}
leftDomainRange.RemoveAll(valuesToRemove);
return(valuesToRemove.Any());
}
internal EncapsulatedVariableDomainValue Compute(TernaryConstraintExpression ternaryConstraint)
{
var valueSetAccumulator = new List <ValueSet>();
var leftSource = ternaryConstraint.GetLeftSource();
var leftPossibleValues = leftSource.PossibleValues;
var expression = ternaryConstraint.ExpressionNode;
IReadOnlyCollection <int> rightPossibleValues;
if (!expression.InnerExpression.RightExpression.IsLiteral)
{
var rightSource = ternaryConstraint.GetRightSource();
rightPossibleValues = new ReadOnlyCollection <int>(rightSource.PossibleValues.ToList());
}
else
{
var lhsVariable = _modelSolverMap.GetModelVariableByName(leftSource.VariableName);
var range = _valueMapper.GetDomainValueFor(lhsVariable);
var modelValue = expression.InnerExpression.RightExpression.GetLiteral();
var solverValue = range.MapTo(modelValue);
rightPossibleValues = new ReadOnlyCollection <int>(new List <int> {
solverValue
});
}
foreach (var leftPossibleValue in leftPossibleValues)
{
foreach (var rightPossibleValue in rightPossibleValues)
{
switch (ternaryConstraint.ExpressionNode.InnerExpression.Operator)
{
case OperatorType.Equals:
if (leftPossibleValue == rightPossibleValue)
{
if (!expression.InnerExpression.RightExpression.IsLiteral)
{
var rightSource = ternaryConstraint.GetRightSource();
var valueSet = new ValueSet(new[] { new Value(_modelSolverMap.GetSolverVariableByName(leftSource.VariableName), leftPossibleValue),
new Value(_modelSolverMap.GetSolverVariableByName(rightSource.VariableName), rightPossibleValue) });
valueSetAccumulator.Add(valueSet);
}
else
{
var valueSet = new ValueSet(new[] { new Value(_modelSolverMap.GetSolverVariableByName(leftSource.VariableName), leftPossibleValue) });
valueSetAccumulator.Add(valueSet);
}
}
break;
case OperatorType.NotEqual:
if (leftPossibleValue != rightPossibleValue)
{
if (!expression.InnerExpression.RightExpression.IsLiteral)
{
var rightSource = ternaryConstraint.GetRightSource();
var valueSet = new ValueSet(new[] { new Value(_modelSolverMap.GetSolverVariableByName(leftSource.VariableName), leftPossibleValue),
new Value(_modelSolverMap.GetSolverVariableByName(rightSource.VariableName), rightPossibleValue) });
valueSetAccumulator.Add(valueSet);
}
else
{
var valueSet = new ValueSet(new[] { new Value(_modelSolverMap.GetSolverVariableByName(leftSource.VariableName), leftPossibleValue) });
valueSetAccumulator.Add(valueSet);
}
}
break;
default:
throw new NotImplementedException();
}
}
}
return(new EncapsulatedVariableDomainValue(ternaryConstraint.EncapsulatedVariable, valueSetAccumulator));
}