Jupyter notebook kernel dies when running gym env.render()

Question

EDIT: When i remove render_mode="rgb_array" it works fine. But this obviously is not a real solution.

I am trying to run a render of a game in Jupyter notebook but each time i run it i get a pop up saying Python 3.7 crashed and the kernel has died.

%matplotlib inline
import numpy as np
import matplotlib.pyplot as plt
import time
import gym
from gym.envs.registration import register
from IPython.display import clear_output

try:
    register(
        id='FrozenLakeNotSlippery-v0', #Name this whatever you want
        entry_point='gym.envs.toy_text:FrozenLakeEnv',
        kwargs={'map_name' : '4x4', 'is_slippery': False},
        max_episode_steps=100,
        reward_threshold=0.78, # optimum = .8196
    ) 
except: 
    print("Already Registered")
    
env = gym.make("FrozenLakeNotSlippery-v0",render_mode='rgb_array')
env.reset()
for step in range(5):
    env.render()
    action = env.action_space.sample()
    observation, reward, terminated, truncated, info = env.step(action)
    time.sleep(0.5)
    print(observation)
    clear_output(wait=True)
    if terminated:
        env.reset()
    
env.close()    

Above is the code I have. Its very straight forward and seems to be a known issue, though I haven't seen anyone have any solutions.

I have tried uninstalling and then re-installing the following packages with pip install:

• ipykernel
• ipython
• jupyter_client
• jupyter_core
• traitlets
• ipython_genutils But i still have the same issue.

Answer 1

I ave found the issue: if you look at the source code for frozen_lake, it only accepts a render_mode of 'human' & 'ansi':

metadata = {'render.modes': ['human', 'ansi']}

so a render_mode="rgb_array", as in my case above, will produce an error.