protected override Expression VisitTrigonometry(MethodCallExpression methodCall, TrigonometryFunction function)
{
Expression argument = methodCall.Arguments[0];
switch (function)
{
case TrigonometryFunction.Sine:
{
Expression innerDerivative = Visit(argument);
return(Arithmeric.Multiply(
innerDerivative,
Trigonometry.Cosine(argument)));
}
case TrigonometryFunction.Cosine:
{
Expression innerDerivative = Visit(argument);
return(Arithmeric.Negate(
Arithmeric.Multiply(
innerDerivative,
Trigonometry.Sine(argument))));
}
default:
throw new NotSupportedException(String.Format("Trigonometric function {0} is not supported.", function.ToString()));
}
}
protected override Expression VisitMultiply(BinaryExpression binaryExpression)
{
Expression leftDerivative = Visit(binaryExpression.Left);
Expression rightDerivative = Visit(binaryExpression.Right);
return(Arithmeric.Add(
Arithmeric.Multiply(leftDerivative, binaryExpression.Right),
Arithmeric.Multiply(rightDerivative, binaryExpression.Left)));
}
protected override Expression VisitParameter(ParameterExpression p)
{
if (p.Name == _variableName)
{
return(Arithmeric.One());
}
return(Arithmeric.Zero());
}
protected override Expression VisitDivide(BinaryExpression binaryExpression)
{
Expression leftDerivative = Visit(binaryExpression.Left);
Expression rightDerivative = Visit(binaryExpression.Right);
return(Arithmeric.Subtract(
Arithmeric.Divide(leftDerivative, binaryExpression.Right),
Arithmeric.Divide(
Arithmeric.Multiply(binaryExpression.Left, rightDerivative),
Arithmeric.Multiply(binaryExpression.Right, binaryExpression.Right))));
}
public static Expression Negate(Expression term)
{
if (Elementary.IsConstantZero(term))
{
return(Arithmeric.Zero());
}
if (term.NodeType == ExpressionType.Negate)
{
UnaryExpression unary = (UnaryExpression)term;
return(unary.Operand);
}
return(Expression.Negate(term));
}
protected override Expression VisitPower(BinaryExpression binaryExpression)
{
Expression leftDerivative = Visit(binaryExpression.Left);
Expression rightDerivative = Visit(binaryExpression.Right);
return(Arithmeric.Multiply(
binaryExpression,
Arithmeric.Add(
Arithmeric.Multiply(
rightDerivative,
Exponential.Ln(binaryExpression.Left)),
Arithmeric.Divide(
Arithmeric.Multiply(binaryExpression.Right, leftDerivative),
binaryExpression.Left))));
}
public static Expression Divide(Expression a, Expression b)
{
if (Elementary.IsConstantZero(a))
{
return(Arithmeric.Zero());
}
if (Elementary.IsConstantOne(b))
{
return(a);
}
TypeInference type = new TypeInference(a, b);
List <Expression> expressions = type.CastToMaxNumericList();
return(Expression.Divide(expressions[0], expressions[1]));
}
protected override Expression VisitConstant(ConstantExpression c)
{
return(Arithmeric.Zero());
}