def update(self, dt):

        global brain
        global last_reward
        global scores
        global last_distance
        global goal_x
        global goal_y
        global longueur
        global largeur
        global lastTime

        longueur = self.width
        largeur = self.height
        if first_update:
            init()

        # code you want to evaluate
        start_time = timeit.default_timer()

        xx = goal_x - self.car.x
        yy = goal_y - self.car.y
        orientation = Vector(*self.car.velocity).angle((xx,yy))/180.
        last_signal = [self.car.signal1, self.car.signal2, self.car.signal3, orientation, -orientation]
        action = brain.update(last_reward, last_signal)
        scores.append(brain.score())
        rotation = action2rotation[action]
        self.car.move(rotation)
        distance = np.sqrt((self.car.x - goal_x)**2 + (self.car.y - goal_y)**2)
        self.ball1.pos = self.car.sensor1
        self.ball2.pos = self.car.sensor2
        self.ball3.pos = self.car.sensor3
        elapsed = timeit.default_timer() - start_time
        lastTime += elapsed

        if sand[int(self.car.x),int(self.car.y)] > 0:
            self.car.velocity = Vector(1, 0).rotate(self.car.angle)
            last_reward = -1
        else: # otherwise
            self.car.velocity = Vector(6, 0).rotate(self.car.angle)
            last_reward = -0.05 * lastTime
            if distance < last_distance:
                last_reward = 0.1

        if self.car.x < 10:
            self.car.x = 10
            last_reward = -1
        if self.car.x > self.width - 10:
            self.car.x = self.width - 10
            last_reward = -1
        if self.car.y < 10:
            self.car.y = 10
            last_reward = -1
        if self.car.y > self.height - 10:
            self.car.y = self.height - 10
            last_reward = -1

        if distance < 100:
            last_reward = -0.4 * lastTime + 1
            print lastTime
            lastTime = 0
            goal_x = self.width-goal_x
            goal_y = self.height-goal_y

        last_distance = distance