There's quite a few. Many are very old. I would have like to use vector-random and got this : Data/Vector/Random/Mersenne.hs:33:18: Could not find module ‘Data.Vector.Fusion.Stream’ It is a member of the hidden package ‘vector-0.10.12.3@vecto_1COyUuV1LrA1IjYnWfJnbs’. Perhaps you need to add ‘vector’ to the build-depends in your .cabal file. Use -v to see a list of the files searched for. Data/Vector/Random/Mersenne.hs:35:18: Could not find module ‘Data.Vector.Fusion.Stream.Size’ It is a member of the hidden package ‘vector-0.10.12.3@vecto_1COyUuV1LrA1IjYnWfJnbs’. Perhaps you need to add ‘vector’ to the build-depends in your .cabal file. Use -v to see a list of the files searched for. I wouldn't be opposed to fixing it, but I'm wondering at this point there isn't a better package to use instead. I'm looking for both integer and floating point random numbers, uniform and gaussian. gsl-random looks promising as does mwc-random. any other suggestions ? Thanks, Brian