Reinforcement Tutorial (DQN)

[sambaPython24]

Hey,
I try to reproduce PyTorch Reinforcement Tutorial (DGN) in

In each time step, the state of the environment need to be evaluated in the function def get_screen()

The line

screen = env.render(mode='rgb_array').transpose((2, 0, 1))

throws an error both in Google Colabs and on my local machine. The error is related to the gym environment

env = gym.make('CartPole-v0').unwrapped

Is there any idea, how to solve this problem and make this tutorial reproducible again?

[litingfeng]

@sambaPython24 Try this blog

[MaxVanDijck]

Just tried to run the tutorial in GoogleColab, returns this error:

/usr/local/lib/python3.7/dist-packages/torchvision/transforms/transforms.py:258: UserWarning: Argument interpolation should be of type InterpolationMode instead of int. Please, use InterpolationMode enum.
  "Argument interpolation should be of type InterpolationMode instead of int. "
---------------------------------------------------------------------------
NoSuchDisplayException                    Traceback (most recent call last)
<ipython-input-5-f1e8f42adf6c> in <module>()
     37 env.reset()
     38 plt.figure()
---> 39 plt.imshow(get_screen().cpu().squeeze(0).permute(1, 2, 0).numpy(),
     40            interpolation='none')
     41 plt.title('Example extracted screen')

9 frames
<ipython-input-5-f1e8f42adf6c> in get_screen()
     12     # Returned screen requested by gym is 400x600x3, but is sometimes larger
     13     # such as 800x1200x3. Transpose it into torch order (CHW).
---> 14     screen = env.render(mode='rgb_array').transpose((2, 0, 1))
     15     # Cart is in the lower half, so strip off the top and bottom of the screen
     16     _, screen_height, screen_width = screen.shape

/usr/local/lib/python3.7/dist-packages/gym/envs/classic_control/cartpole.py in render(self, mode)
    172 
    173         if self.viewer is None:
--> 174             from gym.envs.classic_control import rendering
    175             self.viewer = rendering.Viewer(screen_width, screen_height)
    176             l, r, t, b = -cartwidth / 2, cartwidth / 2, cartheight / 2, -cartheight / 2

/usr/local/lib/python3.7/dist-packages/gym/envs/classic_control/rendering.py in <module>()
     23 
     24 try:
---> 25     from pyglet.gl import *
     26 except ImportError as e:
     27     raise ImportError('''

/usr/local/lib/python3.7/dist-packages/pyglet/gl/__init__.py in <module>()
    242     # trickery is for circular import
    243     _pyglet.gl = _sys.modules[__name__]
--> 244     import pyglet.window

/usr/local/lib/python3.7/dist-packages/pyglet/window/__init__.py in <module>()
   1878 if not _is_pyglet_doc_run:
   1879     pyglet.window = sys.modules[__name__]
-> 1880     gl._create_shadow_window()

/usr/local/lib/python3.7/dist-packages/pyglet/gl/__init__.py in _create_shadow_window()
    218 
    219     from pyglet.window import Window
--> 220     _shadow_window = Window(width=1, height=1, visible=False)
    221     _shadow_window.switch_to()
    222 

/usr/local/lib/python3.7/dist-packages/pyglet/window/xlib/__init__.py in __init__(self, *args, **kwargs)
    163                     self._event_handlers[message] = func
    164 
--> 165         super(XlibWindow, self).__init__(*args, **kwargs)
    166 
    167         global _can_detect_autorepeat

/usr/local/lib/python3.7/dist-packages/pyglet/window/__init__.py in __init__(self, width, height, caption, resizable, style, fullscreen, visible, vsync, display, screen, config, context, mode)
    568 
    569         if not display:
--> 570             display = pyglet.canvas.get_display()
    571 
    572         if not screen:

/usr/local/lib/python3.7/dist-packages/pyglet/canvas/__init__.py in get_display()
     92 
     93     # Otherwise, create a new display and return it.
---> 94     return Display()
     95 
     96 

/usr/local/lib/python3.7/dist-packages/pyglet/canvas/xlib.py in __init__(self, name, x_screen)
    121         self._display = xlib.XOpenDisplay(name)
    122         if not self._display:
--> 123             raise NoSuchDisplayException('Cannot connect to "%s"' % name)
    124 
    125         screen_count = xlib.XScreenCount(self._display)

NoSuchDisplayException: Cannot connect to "None"
<Figure size 432x288 with 0 Axes>