def _enjoy():
model = Model(action_dim=2, max_action=1.)
try:
state_dict = torch.load('trained_models/imitate.pt',
map_location=device)
model.load_state_dict(state_dict)
except:
print('failed to load model')
exit()
model.eval().to(device)
env = launch_env()
env = ResizeWrapper(env)
env = NormalizeWrapper(env)
env = ImgWrapper(env)
env = ActionWrapper(env)
env = DtRewardWrapper(env)
obs = env.reset()
while True:
obs = torch.from_numpy(obs).float().to(device).unsqueeze(0)
action = model(obs)
action = action.squeeze().data.cpu().numpy()
obs, reward, done, info = env.step(action)
env.render()
if done:
if reward < 0:
print('*** FAILED ***')
time.sleep(0.7)
obs = env.reset()
env.render()
def _train(args):
env = launch_env()
env = ResizeWrapper(env)
env = NormalizeWrapper(env)
env = ImgWrapper(env)
env = DtRewardWrapper(env)
env = MetricsWrapper(env)
env = ActionWrapper(env)
print("Initialized Wrappers")
observation_shape = (None, ) + env.observation_space.shape
action_shape = (None, ) + env.action_space.shape
# Create an imperfect demonstrator
expert = PurePursuitExpert(env=env)
observations = []
actions = []
# let's collect our samples
for episode in range(0, args.episodes):
print("Starting episode", episode)
for steps in range(0, args.steps):
# use our 'expert' to predict the next action.
action = expert.predict(None)
observation, reward, done, info = env.step(action)
observations.append(observation)
actions.append(action)
env.reset()
env.close()
actions = np.array(actions)
observations = np.array(observations)
model = Model(action_dim=2, max_action=1.)
model.train().to(device)
# weight_decay is L2 regularization, helps avoid overfitting
optimizer = optim.SGD(model.parameters(), lr=0.0004, weight_decay=1e-3)
avg_loss = 0
for epoch in range(args.epochs):
optimizer.zero_grad()
batch_indices = np.random.randint(0, observations.shape[0],
(args.batch_size))
obs_batch = torch.from_numpy(
observations[batch_indices]).float().to(device)
act_batch = torch.from_numpy(actions[batch_indices]).float().to(device)
model_actions = model(obs_batch)
loss = (model_actions - act_batch).norm(2).mean()
loss.backward()
optimizer.step()
loss = loss.data[0]
avg_loss = avg_loss * 0.995 + loss * 0.005
print('epoch %d, loss=%.3f' % (epoch, avg_loss))
# Periodically save the trained model
if epoch % 200 == 0:
torch.save(model.state_dict(),
'imitation/pytorch/models/imitate.pt')