Hi all, I'm trying to go through the paper Beautiful Differentiation by Conal Elliott and got a bit stuck. So I decided to download the VectorSpace package, which as far as I know implements the paper, and just try and play around with it. Unfortunately when I tried the simple examples at the beginning of the paper I got an error: Prelude Data.VectorSpace> :m Data.Derivative Prelude Data.Derivative> let f1 z = sqrt(3*sin z) Prelude Data.Derivative> f1 (D 2 1) Top level: Couldn't match expected type `Data.VectorSpace.Scalar a' against inferred type `Data.VectorSpace.Scalar (Data.VectorSpace.Scalar a)' NB: `Data.VectorSpace.Scalar' is a type function, and may not be injective <interactive>:1:0: No instances for (Data.MemoTrie.HasTrie (Data.Basis.Basis a), Floating (Data.VectorSpace.Scalar a), Data.VectorSpace.VectorSpace (Data.VectorSpace.Scalar a)) arising from a use of `f1' at <interactive>:1:0-9 Possible fix: add an instance declaration for (Data.MemoTrie.HasTrie (Data.Basis.Basis a), Floating (Data.VectorSpace.Scalar a), Data.VectorSpace.VectorSpace (Data.VectorSpace.Scalar a)) In the expression: f1 (D 2 1) In the definition of `it': it = f1 (D 2 1) <interactive>:1:8: No instance for (Num (a Data.LinearMap.:-* (a :> Data.VectorSpace.Scalar a))) arising from the literal `1' at <interactive>:1:8 Possible fix: add an instance declaration for (Num (a Data.LinearMap.:-* (a :> Data.VectorSpace.Scalar a))) In the second argument of `D', namely `1' In the first argument of `f1', namely `(D 2 1)' In the expression: f1 (D 2 1) Which was completely incomprehensible to me. I tried looking at the documentation but I couldn't find anything about actually using the library. Does anyone have any experience using this library and maybe have some examples of it's use? Thanks Chris Witte