CartPole-v0的意外观察空间

Question

我为CartPole-v0进行内省而获得的观察空间令我感到惊讶。

根据the official doc，这是我应该得到的：

但是，这就是我得到的：

print(env.observation_space.low)
print(env.observation_space.high)
#[-4.8000002e+00 -3.4028235e+38 -4.1887903e-01 -3.4028235e+38]
#[4.8000002e+00 3.4028235e+38 4.1887903e-01 3.4028235e+38]

我正在使用latest version of gym：

!pip list|grep gym
gym                 0.12.1   

知道发生了什么吗？

Answer 1

如代码中所述，似乎您正在获得预期的行为，这有点令人困惑。一方面，cart position的观察空间为[-4.8，4.8]，但是实际上，该事件应在购物车达到极限[-2.4，2.4]时结束。对于pole angle，情况类似。

class CartPoleEnv(gym.Env):
"""
Description:
    A pole is attached by an un-actuated joint to a cart, which moves along a frictionless track. The pendulum starts upright, and the goal is to prevent it from falling over by increasing and reducing the cart's velocity.

Source:
    This environment corresponds to the version of the cart-pole problem described by Barto, Sutton, and Anderson

Observation: 
    Type: Box(4)
    Num Observation                 Min         Max
    0   Cart Position             -4.8            4.8
    1   Cart Velocity             -Inf            Inf
    2   Pole Angle                 -24 deg        24 deg
    3   Pole Velocity At Tip      -Inf            Inf

Actions:
    Type: Discrete(2)
    Num Action
    0   Push cart to the left
    1   Push cart to the right

    Note: The amount the velocity that is reduced or increased is not fixed; it depends on the angle the pole is pointing. This is because the center of gravity of the pole increases the amount of energy needed to move the cart underneath it

Reward:
    Reward is 1 for every step taken, including the termination step

Starting State:
    All observations are assigned a uniform random value in [-0.05..0.05]

Episode Termination:
    Pole Angle is more than 12 degrees
    Cart Position is more than 2.4 (center of the cart reaches the edge of the display)
    Episode length is greater than 200
    Solved Requirements
    Considered solved when the average reward is greater than or equal to 195.0 over 100 consecutive trials.
"""

在this link中，您可以阅读相关的Github问题。

*请注意，24度等于4.1887903e-01弧度。

Answer 2

看起来像过时的文档，已经创建了一个问题：https://github.com/openai/gym/issues/368