- r i j | i > j = 0
- | i == j = sqrt(m ! (i,j) - sum [(r k i)**2 | k <- [0..i-1]])
- | i < j = (((m ! (i,j)) - sum [(r k i)*(r k j) | k <- [0..i-1]]))/(r i i)
+ r i j | i == j = sqrt(m ! (i,j) - sum [(r k i)**2 | k <- [0..i-1]])
+ | i < j =
+ (((m ! (i,j)) - sum [(r k i)*(r k j) | k <- [0..i-1]]))/(r i i)
+ | otherwise = 0