我正在尝试让 AI-Gym 演示在 Jupyter 笔记本中显示。我在 Atari 演示中得到了很好的结果，Breakout-v0而在 cart-pole 演示中得到了一个困难的错误消息CartPole-v0。两者都可以在笔记本电脑之外正常工作。以下是最小的细节：
没有木星
在控制台：
$ pip install gym[atari] &> /dev/null
$ /anaconda3/bin/python3
Python 3.6.3 |Anaconda, Inc.| (default, Oct 6 2017, 12:04:38)
[GCC 4.2.1 Compatible Clang 4.0.1 (tags/RELEASE_401/final)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import gym
>>> env = gym.make('Breakout-v0')
>>> env.reset()
>>> env.render()
结果：
现在，同样使用 cart-pole，在一个新的 Python 会话中：
$ pip install gym &> /dev/null
$ /anaconda3/bin/python3
Python 3.6.3 |Anaconda, Inc.| (default, Oct 6 2017, 12:04:38)
[GCC 4.2.1 Compatible Clang 4.0.1 (tags/RELEASE_401/final)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> env = gym.make('CartPole-v0')
>>> env.reset()
>>> env.render()
与上面 Python 代码的唯一区别是演示的名称：CartPole-v0而不是Breakout-v0.
结果：
与木星
遵循这个 SO 问题的一些提示：How to run OpenAI Gym .render() over a server，我有这个用于Breakout演示：
或者，在文本中：
import gym
from IPython import display
import matplotlib
import matplotlib.pyplot as plt
%matplotlib inline
env = gym.make('Breakout-v0')
env.reset()
img = plt.imshow(env.render(mode='rgb_array'))
img.set_data(env.render(mode='rgb_array'))
display.display(plt.gcf())
display.clear_output(wait=True)
现在，对于购物车杆，再次使用新的内核会话和笔记本，唯一的区别是演示的名称：
import gym
from IPython import display
import matplotlib
import matplotlib.pyplot as plt
%matplotlib inline
env = gym.make('CartPole-v0')
env.reset()
img = plt.imshow(env.render(mode='rgb_array'))
img.set_data(env.render(mode='rgb_array'))
display.display(plt.gcf())
display.clear_output(wait=True)
我收到一条很长的错误消息，抱怨某些 pyglet 类是抽象的。堆栈跟踪的最后一个元素如下：
/anaconda3/lib/python3.6/site-packages/pyglet/canvas/base.py in get_screens(self)
63 :rtype: list of :class:`Screen`
64 '''
---> 65 raise NotImplementedError('abstract')
66
67 def get_default_screen(self):
NotImplementedError: abstract
整个堆栈跟踪位于底部以供检查。我通读了它，但无法确定问题以及如何解决它。我会很感激你的建议。
总结一下，
NO JUPYTER:
Breakout: OK
CartPole: OK
JUPYTER:
Breakout: OK
CartPole: ERROR
整个堆栈跟踪如下：
NotImplementedError Traceback (most recent call last)
<ipython-input-1-df4d39818fe3> in <module>()
6 env = gym.make('CartPole-v0')
7 env.reset()
----> 8 img = plt.imshow(env.render(mode='rgb_array'))
9 img.set_data(env.render(mode='rgb_array'))
10 display.display(plt.gcf())
/anaconda3/lib/python3.6/site-packages/gym/core.py in render(self, mode, close)
148 elif mode not in modes:
149 raise error.UnsupportedMode('Unsupported rendering mode: {}. (Supported modes for {}: {})'.format(mode, self, modes))
--> 150 return self._render(mode=mode, close=close)
151
152 def close(self):
/anaconda3/lib/python3.6/site-packages/gym/core.py in _render(self, mode, close)
284
285 def _render(self, mode='human', close=False):
--> 286 return self.env.render(mode, close)
287
288 def _close(self):
/anaconda3/lib/python3.6/site-packages/gym/core.py in render(self, mode, close)
148 elif mode not in modes:
149 raise error.UnsupportedMode('Unsupported rendering mode: {}. (Supported modes for {}: {})'.format(mode, self, modes))
--> 150 return self._render(mode=mode, close=close)
151
152 def close(self):
/anaconda3/lib/python3.6/site-packages/gym/envs/classic_control/cartpole.py in _render(self, mode, close)
114 if self.viewer is None:
115 from gym.envs.classic_control import rendering
--> 116 self.viewer = rendering.Viewer(screen_width, screen_height)
117 l,r,t,b = -cartwidth/2, cartwidth/2, cartheight/2, -cartheight/2
118 axleoffset =cartheight/4.0
/anaconda3/lib/python3.6/site-packages/gym/envs/classic_control/rendering.py in __init__(self, width, height, display)
49 self.width = width
50 self.height = height
---> 51 self.window = pyglet.window.Window(width=width, height=height, display=display)
52 self.window.on_close = self.window_closed_by_user
53 self.geoms = []
/anaconda3/lib/python3.6/site-packages/pyglet/window/__init__.py in __init__(self, width, height, caption, resizable, style, fullscreen, visible, vsync, display, screen, config, context, mode)
502
503 if not screen:
--> 504 screen = display.get_default_screen()
505
506 if not config:
/anaconda3/lib/python3.6/site-packages/pyglet/canvas/base.py in get_default_screen(self)
71 :rtype: :class:`Screen`
72 '''
---> 73 return self.get_screens()[0]
74
75 def get_windows(self):
/anaconda3/lib/python3.6/site-packages/pyglet/canvas/base.py in get_screens(self)
63 :rtype: list of :class:`Screen`
64 '''
---> 65 raise NotImplementedError('abstract')
66
67 def get_default_screen(self):
NotImplementedError: abstract