private SolverVariable ExtractVariableFrom(ExpressionNode expressionConstraintNode)
{
switch (expressionConstraintNode.InnerExpression)
{
case SingletonVariableReferenceNode singletonVariableReference:
return(_modelSolverMap.GetSolverSingletonVariableByName(singletonVariableReference.VariableName));
case AggregateVariableReferenceNode aggregateVariableReference:
return(_modelSolverMap.GetSolverAggregateVariableByName(aggregateVariableReference.VariableName,
aggregateVariableReference.SubscriptStatement.Subscript));
case SingletonVariableReferenceExpressionNode singletonVariableExpression:
return(_modelSolverMap.GetSolverSingletonVariableByName(singletonVariableExpression.VariableReference.VariableName));
case AggregateVariableReferenceExpressionNode aggregateVariableExpression:
return(_modelSolverMap.GetSolverAggregateVariableByName(aggregateVariableExpression.VariableReference.VariableName,
aggregateVariableExpression.VariableReference.SubscriptStatement.Subscript));
case BucketVariableReferenceNode bucketVariableReference:
return(_modelSolverMap.GetSolverBucketVariableByName(bucketVariableReference.BucketName,
bucketVariableReference.SubscriptStatement.Subscript,
bucketVariableReference.VariableName));
default:
throw new NotImplementedException();
}
}
private void CreateArcFrom(AllDifferentConstraintModel constraint)
{
var solverAggregateVariable = _modelSolverMap.GetSolverAggregateVariableByName(constraint.Expression.Text);
/*
* Iterate through all variables inside the aggregate and ensure
* that each variable is not equal to all variables to their
* right. The not equal operator is commutative so there is no need
* to express the constraint the other way around.
*/
for (var i = 0; i < solverAggregateVariable.Variables.Count; i++)
{
for (var z = i + 1; z < solverAggregateVariable.Variables.Count; z++)
{
var expressionText = $"${solverAggregateVariable.Name}[{i}] <> ${solverAggregateVariable.Name}[{z}]";
var interpreter = new ConstraintExpressionParser();
var parseResult = interpreter.Parse(expressionText);
Debug.Assert(parseResult.IsSuccess);
_constraintNetwork.AddArc(_arcBuilder.Build(parseResult.Root));
}
}
}