protected override Expression TransformFunction(FunctionExpression functionExpression)
{
if (functionExpression.Function == Operators.Diff)
{
VariableListExtractor extractor = new VariableListExtractor();
extractor.Visit(functionExpression[1]);
IReadOnlyList <Variable> variables = extractor.Variables;
if (variables.Count == 0)
{
throw new InvalidOperationException("Cannot calculate derivative by constant");
}
throw new NotImplementedException();
}
if (functionExpression.Function == Operators.Plus)
{
return(Transform(functionExpression[0]));
}
if (functionExpression.Function is Operator)
{
SumAggregator aggregator = new SumAggregator();
aggregator.VisitFunction(functionExpression);
return(aggregator.ToExpression());
}
return(functionExpression.Function.Apply(functionExpression.Select(Transform)));
}
public override void VisitFunction(FunctionExpression functionExpression)
{
if (functionExpression.Function == Operators.Plus)
{
Visit(functionExpression[0].Simplify());
}
else if (functionExpression.Function == Operators.Negate)
{
_sign = !_sign;
Visit(functionExpression[0].Simplify());
}
else if (functionExpression.Function == Operators.Multiply)
{
foreach (Expression factor in functionExpression)
{
Visit(factor.Simplify());
}
}
else if (functionExpression.Function == Operators.Divide)
{
Visit(functionExpression[0].Simplify());
ProductAggregator aggregator = new ProductAggregator();
aggregator.Visit(functionExpression[1].Simplify());
_sign ^= aggregator._sign;
_value /= aggregator._value;
Visit(aggregator._divider);
foreach (Expression factor in aggregator._factors)
{
_divider *= factor;
}
}
else
{
_factors = _factors.Add(functionExpression.Function.
Apply(functionExpression.Select(arg => arg.Simplify())));
}
}
protected override Expression TransformFunction(FunctionExpression function) => new FunctionExpression(function.Function, function.Select(Transform).ToArray());