Hello all. I'd be interested in getting some feedback on how to do this linear interpolation function a little more cleanly. The normal way that this is taught is to find the set of indices in the x list that bracket the input value, then use the slope between these points to calculate the y value for the input value. I had a version working at one point using !! to access particular elements but I wasn't sure which one was the better solution. linterp :: [Double] -> [Double] -> Double -> Double linterp (x1:x2:xs) (y1:y2:ys) x | x <= x2 || xs == [] = linterpPair x1 x2 y1 y2 x | otherwise = linterp (x2:xs) (y2:ys) x where linterpPair x1 x2 y1 y2 x = x1 + (x - x1) * (y2 - y1) / (x2 - x1) Gordon James Miller Promisemark, Inc. Senior Computer Scientist gmiller@promisemark.com (571)330-9012 Light travels faster than sound. That is why some people appear bright until you hear them speak.