//f(x) = c*x^y => f'(x) = c*y*x^y-1 c,y - constant
private static Expression GetDerivativeOfParametr(Expression function)
{
if (function is ParameterExpression)
{
return(Expression.Constant(1d));
}
var functionFeatures = FunctionFeatures.GetFeatures(function as BinaryExpression);
return(Expression.Multiply(
Expression.Constant(functionFeatures.Constant * functionFeatures.Pow),
Expression.Call(null,
typeof(Math).GetMethod("Pow"),
x,
Expression.Constant((functionFeatures.Pow - 1)))));
}
private static FunctionFeatures CalculateFeatures(BinaryExpression function)
{
var funcFeatures = new FunctionFeatures();
funcFeatures += CheckSubExpression(function.Left);
funcFeatures += CheckSubExpression(function.Right);
FunctionFeatures CheckSubExpression(Expression checkExpression)
{
var ff = new FunctionFeatures();
if (!IsTheEndNode(checkExpression))
{
ff += CalculateFeatures(checkExpression as BinaryExpression);
}
else
{
if (checkExpression is ConstantExpression constant)
{
ff.Constant += (double)constant.Value;
}
else
{
ff.Pow++;
}
}
return(ff);
}
bool IsTheEndNode(Expression checkExpression)
{
return(checkExpression is ConstantExpression || checkExpression is ParameterExpression);
}
return(funcFeatures);
}
