mpla.hs

mpla :: [[Float]] -> [Float] -> [Float] -> (Bool, [Float])
mpla [] [] c = (False, c)
mpla (a:ax) (b:by) (c:cc) = (fl&&(s<0), rc)
  where
    s = b*(c+(mdot a cc))
    nc = case (s<0) of
      True -> [c+(b*head a)] ++ (vadd a cc b)
      False -> [c] ++ cc
    (fl, rc) = mpla ax by nc

vadd :: [Float] -> [Float] -> Float -> [Float]
vadd [] [] _ = []
vadd (a:ax) (b:bx) c = [a+b*c] ++ (vadd ax bx c)

mdot :: [Float] -> [Float] -> Float
mdot [] [] = 0
mdot (a:ax) (b:bx) = a*b + (mdot ax bx)

main = print (mpla [[-1,1],[-2,-1],[3,3],[4,-4]] [1,1,-1,-1] [0,1,2])