[Haskell-cafe] Gaussian elimination

Hi, I came up with the following extremely compact version of Gaussian elimination for matrices represented as functions. I searched the web but found nothing resembling it, probably because of its inefficiency. Has anybody seen something like it before? Thanks Tobias gauss :: Int -> (Int -> Int -> Rational) -> Maybe (Int -> Int -> Rational) gauss 0 a = Just a gauss (n+1) a = case dropWhile (\i -> a i n == 0) [0..n] of [] -> Nothing (k:_) -> let ak' j = a k j / a k n a' i = if i == k then ak' else (\j -> a i j - a i n * ak' j) in gauss n (swap k n a') swap :: Int -> Int -> (Int -> a) -> (Int -> a) swap k n f = g where g x | x == k = f n | x == n = f k | otherwise = f x