AI class: Simple Motion Model

SimpleMotionModel.hs

-- https://www.ai-class.com/course/video/quizquestion/285

data State = S { x     :: Double
               , y     :: Double
               , theta :: Double
               , v     :: Double
               , omega :: Double
               , dt    :: Double
               } deriving (Show)

iter :: Int -> (a -> a) -> a -> a
iter 0 _ a = a
iter n f a = iter (n-1) f (f a)

step :: State -> State
step a = S { x     = x a + dt a * v a * (cos $ theta a)
           , y     = y a + dt a * v a * (sin $ theta a)
           , theta = theta a + omega a * dt a
           , v     = v a
           , omega = omega a
           , dt    = dt a
           }

main :: IO ()
main = print $ iter numSteps step startState
  where startState = S { x = 0
                       , y = 0
                       , theta = 0
                       , v = 10
                       , omega = pi / 8
                       , dt = 4
                       }
        numSteps = 4

-- Note to myself: I should think before I compute a solution.