Function grid_5x5

rl/grid_world.py:337–369

(step_cost=-0.1)

def grid_5x5(step_cost=-0.1):
  g = Grid(5, 5, (4, 0))
  rewards = {(0, 4): 1, (1, 4): -1}
  actions = {
    (0, 0): ('D', 'R'),
    (0, 1): ('L', 'R'),
    (0, 2): ('L', 'R'),
    (0, 3): ('L', 'D', 'R'),
    (1, 0): ('U', 'D', 'R'),
    (1, 1): ('U', 'D', 'L'),
    (1, 3): ('U', 'D', 'R'),
    (2, 0): ('U', 'D', 'R'),
    (2, 1): ('U', 'L', 'R'),
    (2, 2): ('L', 'R', 'D'),
    (2, 3): ('L', 'R', 'U'),
    (2, 4): ('L', 'U', 'D'),
    (3, 0): ('U', 'D'),
    (3, 2): ('U', 'D'),
    (3, 4): ('U', 'D'),
    (4, 0): ('U', 'R'),
    (4, 1): ('L', 'R'),
    (4, 2): ('L', 'R', 'U'),
    (4, 3): ('L', 'R'),
    (4, 4): ('L', 'U'),
  }
  g.set(rewards, actions)

  # non-terminal states
  visitable_states = actions.keys()
  for s in visitable_states:
    g.rewards[s] = step_cost

  return g