Gerhard Navratil wrote:
I need a library that provides partial derivatives for functions. The solution I came up with is based on a datatype using reversed polish notation to store the function:
<<lots of code>>
The solution works but is not very elegant. The complete module is appended to the mail.
Does anyone have a more elegant solution or is there a package that provides derivatives in a similar way?
A simple way to make it more ellegant is to use smart constructors, so you don't have to check to prevent zeroes everywhere:
sub :: Fkt a -> Fkt a -> Fkt a sub a b | b == 0 = a | a == 0 = Neg b | otherwise = Sub a b -- etc.
Now you can use this smart constructor instead of the real constructor without worry, like:
derivative name (Sub a b) = sub (derivative name a) (derivative name b) -- etc.
Twan