AttributeError: module '_Box2D' has no attribute 'RAND_LIMIT_swigconstant'

Question

I am trying to run a lunar_lander on reinforcement learning, but when I run it, it occurs an error. Plus my computer is osx system.

Here is the code of lunar lander:

import numpy as np
import gym
import csv

from keras.models import Sequential
from keras.layers import Dense, Activation, Flatten
from keras.optimizers import Adam

from rl.agents.dqn import DQNAgent
from rl.policy import BoltzmannQPolicy, EpsGreedyQPolicy
from rl.memory import SequentialMemory

import io
import sys
import csv

# Path environment changed to make things work properly
# export DYLD_FALLBACK_LIBRARY_PATH=$DYLD_FALLBACK_LIBRARY_PATH:/usr/lib


# Get the environment and extract the number of actions.
ENV_NAME = 'LunarLander-v2'
env = gym.make(ENV_NAME)
np.random.seed(123)
env.seed(123)
nb_actions = env.action_space.n

# Next, we build a very simple model.
model = Sequential()
model.add(Flatten(input_shape=(1,) + env.observation_space.shape))
model.add(Dense(16))
model.add(Activation('relu'))
model.add(Dense(16))
model.add(Activation('relu'))
model.add(Dense(16))
model.add(Activation('relu'))
model.add(Dense(nb_actions))
model.add(Activation('linear'))
#print(model.summary())

# Finally, we configure and compile our agent. You can use every built-in Keras optimizer and
# even the metrics!
memory = SequentialMemory(limit=300000, window_length=1)
policy = EpsGreedyQPolicy()
dqn = DQNAgent(model=model, nb_actions=nb_actions, memory=memory, nb_steps_warmup=10,
               target_model_update=1e-2, policy=policy)
dqn.compile(Adam(lr=1e-3), metrics=['mae'])

# After training is done, we save the final weights.
dqn.load_weights('dqn_{}_weights.h5f'.format(ENV_NAME))

# Redirect stdout to capture test results
old_stdout = sys.stdout
sys.stdout = mystdout = io.StringIO()

# Evaluate our algorithm for a few episodes.
dqn.test(env, nb_episodes=200, visualize=False)

# Reset stdout
sys.stdout = old_stdout

results_text = mystdout.getvalue()

# Print results text
print("results")
print(results_text)

# Extact a rewards list from the results
total_rewards = list()
for idx, line in enumerate(results_text.split('\n')):
    if idx > 0 and len(line) > 1:
        reward = float(line.split(':')[2].split(',')[0].strip())
        total_rewards.append(reward)

# Print rewards and average
print("total rewards", total_rewards)
print("average total reward", np.mean(total_rewards))

# Write total rewards to file
f = open("lunarlander_rl_rewards.csv",'w')
wr = csv.writer(f)
for r in total_rewards:
     wr.writerow([r,])
f.close()

Here is the error:

Traceback (most recent call last):
  File "/s/user/Document/Semester2/Advanced Machine Learning/Lab/Lab6/lunar_lander_ml_states_player.py", line 23, in <module>
    env = gym.make(ENV_NAME)
  File "/s/user/anaconda/envs/untitled/lib/python3.6/site-packages/gym/envs/registration.py", line 167, in make
    return registry.make(id)
  File "/s/user/anaconda/envs/untitled/lib/python3.6/site-packages/gym/envs/registration.py", line 119, in make
    env = spec.make()
  File "/s/user/anaconda/envs/untitled/lib/python3.6/site-packages/gym/envs/registration.py", line 85, in make
    cls = load(self._entry_point)
  File "/s/user/anaconda/envs/untitled/lib/python3.6/site-packages/gym/envs/registration.py", line 14, in load
    result = entry_point.load(False)
  File "/s/user/anaconda/envs/untitled/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2405, in load
    return self.resolve()
  File "/s/user/anaconda/envs/untitled/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2411, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/s/user/anaconda/envs/untitled/lib/python3.6/site-packages/gym/envs/box2d/__init__.py", line 1, in <module>
    from gym.envs.box2d.lunar_lander import LunarLander
  File "/s/user/anaconda/envs/untitled/lib/python3.6/site-packages/gym/envs/box2d/lunar_lander.py", line 4, in <module>
    import Box2D
  File "/s/user/anaconda/envs/untitled/lib/python3.6/site-packages/Box2D/__init__.py", line 20, in <module>
    from .Box2D import *
  File "/s/user/anaconda/envs/untitled/lib/python3.6/site-packages/Box2D/Box2D.py", line 435, in <module>
    _Box2D.RAND_LIMIT_swigconstant(_Box2D)
AttributeError: module '_Box2D' has no attribute 'RAND_LIMIT_swigconstant'

I tried to reinstall Box2d by following the guide of https://github.com/pybox2d/pybox2d/blob/master/INSTALL.md but it still doesn't work, could anyone help me ?

Answer 1

for me it was a combination of two things.

First I wanted to install pip install box2d box2d-kengz, but got an error about a failure to build wheels.

I tried many suggested things to fix the issue with wheels, at the end this command solved it: pip install --upgrade setuptools wheel

After that I was able to install the python packages and solve the problem.

Good luck :)

Answer 2

pip install gym[all] worked for me

Answer 3

In case you already had box2d-py, uninstall and reinstall it

pip uninstall box2d-py

then,

pip install box2d-py

that worked for me.

Answer 4

"pip install box2d box2d-kengz --user" worked for me :)

Just in case other people might find it informative.

Answer 5

Try this 'pip3 install box2d box2d-kengz'