observation_model = ObservationModel(
args.symbolic_env, env.observation_size, args.belief_size, args.state_size,
args.embedding_size, args.activation_function).to(device=args.device)
reward_model = RewardModel(args.belief_size, args.state_size, args.hidden_size,
args.activation_function).to(device=args.device)
encoder = Encoder(args.symbolic_env, env.observation_size, args.embedding_size,
args.activation_function).to(device=args.device)
param_list = list(transition_model.parameters()) + list(
observation_model.parameters()) + list(reward_model.parameters()) + list(
encoder.parameters())
optimiser = optim.Adam(param_list, lr=args.learning_rate, eps=1e-4)
if args.load_checkpoint > 0:
model_dicts = torch.load(
os.path.join(results_dir, 'models_%d.pth' % args.load_checkpoint))
transition_model.load_state_dict(model_dicts['transition_model'])
observation_model.load_state_dict(model_dicts['observation_model'])
reward_model.load_state_dict(model_dicts['reward_model'])
encoder.load_state_dict(model_dicts['encoder'])
optimiser.load_state_dict(model_dicts['optimiser'])
mode = "continuous"
num_actions = -1
if type(env._env.action_space) == gym.spaces.discrete.Discrete:
mode = "discrete"
num_actions = env._env.action_space.n
planner = MPCPlanner(env.action_size,
args.planning_horizon,
args.optimisation_iters,
args.candidates,
args.top_candidates,
transition_model,
class Trainer():
def __init__(self, params, experience_replay_buffer,metrics,results_dir,env):
self.parms = params
self.D = experience_replay_buffer
self.metrics = metrics
self.env = env
self.tested_episodes = 0
self.statistics_path = results_dir+'/statistics'
self.model_path = results_dir+'/model'
self.video_path = results_dir+'/video'
self.rew_vs_pred_rew_path = results_dir+'/rew_vs_pred_rew'
self.dump_plan_path = results_dir+'/dump_plan'
#if folder do not exists, create it
os.makedirs(self.statistics_path, exist_ok=True)
os.makedirs(self.model_path, exist_ok=True)
os.makedirs(self.video_path, exist_ok=True)
os.makedirs(self.rew_vs_pred_rew_path, exist_ok=True)
os.makedirs(self.dump_plan_path, exist_ok=True)
# Create models
self.transition_model = TransitionModel(self.parms.belief_size, self.parms.state_size, self.env.action_size, self.parms.hidden_size, self.parms.embedding_size, self.parms.activation_function).to(device=self.parms.device)
self.observation_model = ObservationModel(self.parms.belief_size, self.parms.state_size, self.parms.embedding_size, self.parms.activation_function).to(device=self.parms.device)
self.reward_model = RewardModel(self.parms.belief_size, self.parms.state_size, self.parms.hidden_size, self.parms.activation_function).to(device=self.parms.device)
self.encoder = Encoder(self.parms.embedding_size,self.parms.activation_function).to(device=self.parms.device)
self.param_list = list(self.transition_model.parameters()) + list(self.observation_model.parameters()) + list(self.reward_model.parameters()) + list(self.encoder.parameters())
self.optimiser = optim.Adam(self.param_list, lr=0 if self.parms.learning_rate_schedule != 0 else self.parms.learning_rate, eps=self.parms.adam_epsilon)
self.planner = MPCPlanner(self.env.action_size, self.parms.planning_horizon, self.parms.optimisation_iters, self.parms.candidates, self.parms.top_candidates, self.transition_model, self.reward_model,self.env.action_range[0], self.env.action_range[1])
global_prior = Normal(torch.zeros(self.parms.batch_size, self.parms.state_size, device=self.parms.device), torch.ones(self.parms.batch_size, self.parms.state_size, device=self.parms.device)) # Global prior N(0, I)
self.free_nats = torch.full((1, ), self.parms.free_nats, dtype=torch.float32, device=self.parms.device) # Allowed deviation in KL divergence
def load_checkpoints(self):
self.metrics = torch.load(self.model_path+'/metrics.pth')
model_path = self.model_path+'/best_model'
os.makedirs(model_path, exist_ok=True)
files = os.listdir(model_path)
if files:
checkpoint = [f for f in files if os.path.isfile(os.path.join(model_path, f))]
model_dicts = torch.load(os.path.join(model_path, checkpoint[0]),map_location=self.parms.device)
self.transition_model.load_state_dict(model_dicts['transition_model'])
self.observation_model.load_state_dict(model_dicts['observation_model'])
self.reward_model.load_state_dict(model_dicts['reward_model'])
self.encoder.load_state_dict(model_dicts['encoder'])
self.optimiser.load_state_dict(model_dicts['optimiser'])
print("Loading models checkpoints!")
else:
print("Checkpoints not found!")
def update_belief_and_act(self, env, belief, posterior_state, action, observation, reward, min_action=-inf, max_action=inf,explore=False):
# Infer belief over current state q(s_t|o≤t,a<t) from the history
encoded_obs = self.encoder(observation).unsqueeze(dim=0).to(device=self.parms.device)
belief, _, _, _, posterior_state, _, _ = self.transition_model(posterior_state, action.unsqueeze(dim=0), belief, encoded_obs) # Action and observation need extra time dimension
belief, posterior_state = belief.squeeze(dim=0), posterior_state.squeeze(dim=0) # Remove time dimension from belief/state
action,pred_next_rew,_,_,_ = self.planner(belief, posterior_state,explore) # Get action from planner(q(s_t|o≤t,a<t), p)
if explore:
action = action + self.parms.action_noise * torch.randn_like(action) # Add exploration noise ε ~ p(ε) to the action
action.clamp_(min=min_action, max=max_action) # Clip action range
next_observation, reward, done = env.step(action.cpu() if isinstance(env, EnvBatcher) else action[0].cpu()) # If single env is istanceted perform single action (get item from list), else perform all actions
return belief, posterior_state, action, next_observation, reward, done,pred_next_rew
def fit_buffer(self,episode):
####
# Fit data taken from buffer
######
# Model fitting
losses = []
tqdm.write("Fitting buffer")
for s in tqdm(range(self.parms.collect_interval)):
# Draw sequence chunks {(o_t, a_t, r_t+1, terminal_t+1)} ~ D uniformly at random from the dataset (including terminal flags)
observations, actions, rewards, nonterminals = self.D.sample(self.parms.batch_size, self.parms.chunk_size) # Transitions start at time t = 0
# Create initial belief and state for time t = 0
init_belief, init_state = torch.zeros(self.parms.batch_size, self.parms.belief_size, device=self.parms.device), torch.zeros(self.parms.batch_size, self.parms.state_size, device=self.parms.device)
encoded_obs = bottle(self.encoder, (observations[1:], ))
# Update belief/state using posterior from previous belief/state, previous action and current observation (over entire sequence at once)
beliefs, prior_states, prior_means, prior_std_devs, posterior_states, posterior_means, posterior_std_devs = self.transition_model(init_state, actions[:-1], init_belief, encoded_obs, nonterminals[:-1])
# Calculate observation likelihood, reward likelihood and KL losses (for t = 0 only for latent overshooting); sum over final dims, average over batch and time (original implementation, though paper seems to miss 1/T scaling?)
# LOSS
observation_loss = F.mse_loss(bottle(self.observation_model, (beliefs, posterior_states)), observations[1:], reduction='none').sum((2, 3, 4)).mean(dim=(0, 1))
kl_loss = torch.max(kl_divergence(Normal(posterior_means, posterior_std_devs), Normal(prior_means, prior_std_devs)).sum(dim=2), self.free_nats).mean(dim=(0, 1))
reward_loss = F.mse_loss(bottle(self.reward_model, (beliefs, posterior_states)), rewards[:-1], reduction='none').mean(dim=(0, 1))
# Update model parameters
self.optimiser.zero_grad()
(observation_loss + reward_loss + kl_loss).backward() # BACKPROPAGATION
nn.utils.clip_grad_norm_(self.param_list, self.parms.grad_clip_norm, norm_type=2)
self.optimiser.step()
# Store (0) observation loss (1) reward loss (2) KL loss
losses.append([observation_loss.item(), reward_loss.item(), kl_loss.item()])#, regularizer_loss.item()])
#save statistics and plot them
losses = tuple(zip(*losses))
self.metrics['observation_loss'].append(losses[0])
self.metrics['reward_loss'].append(losses[1])
self.metrics['kl_loss'].append(losses[2])
lineplot(self.metrics['episodes'][-len(self.metrics['observation_loss']):], self.metrics['observation_loss'], 'observation_loss', self.statistics_path)
lineplot(self.metrics['episodes'][-len(self.metrics['reward_loss']):], self.metrics['reward_loss'], 'reward_loss', self.statistics_path)
lineplot(self.metrics['episodes'][-len(self.metrics['kl_loss']):], self.metrics['kl_loss'], 'kl_loss', self.statistics_path)
def explore_and_collect(self,episode):
tqdm.write("Collect new data:")
reward = 0
# Data collection
with torch.no_grad():
done = False
observation, total_reward = self.env.reset(), 0
belief, posterior_state, action = torch.zeros(1, self.parms.belief_size, device=self.parms.device), torch.zeros(1, self.parms.state_size, device=self.parms.device), torch.zeros(1, self.env.action_size, device=self.parms.device)
t = 0
real_rew = []
predicted_rew = []
total_steps = self.parms.max_episode_length // self.env.action_repeat
explore = True
for t in tqdm(range(total_steps)):
# Here we need to explore
belief, posterior_state, action, next_observation, reward, done, pred_next_rew = self.update_belief_and_act(self.env, belief, posterior_state, action, observation.to(device=self.parms.device), [reward], self.env.action_range[0], self.env.action_range[1], explore=explore)
self.D.append(observation, action.cpu(), reward, done)
real_rew.append(reward)
predicted_rew.append(pred_next_rew.to(device=self.parms.device).item())
total_reward += reward
observation = next_observation
if self.parms.flag_render:
env.render()
if done:
break
# Update and plot train reward metrics
self.metrics['steps'].append( (t * self.env.action_repeat) + self.metrics['steps'][-1])
self.metrics['episodes'].append(episode)
self.metrics['train_rewards'].append(total_reward)
self.metrics['predicted_rewards'].append(np.array(predicted_rew).sum())
lineplot(self.metrics['episodes'][-len(self.metrics['train_rewards']):], self.metrics['train_rewards'], 'train_rewards', self.statistics_path)
double_lineplot(self.metrics['episodes'], self.metrics['train_rewards'], self.metrics['predicted_rewards'], "train_r_vs_pr", self.statistics_path)
def train_models(self):
# from (init_episodes) to (training_episodes + init_episodes)
tqdm.write("Start training.")
for episode in tqdm(range(self.parms.num_init_episodes +1, self.parms.training_episodes) ):
self.fit_buffer(episode)
self.explore_and_collect(episode)
if episode % self.parms.test_interval == 0:
self.test_model(episode)
torch.save(self.metrics, os.path.join(self.model_path, 'metrics.pth'))
torch.save({'transition_model': self.transition_model.state_dict(), 'observation_model': self.observation_model.state_dict(), 'reward_model': self.reward_model.state_dict(), 'encoder': self.encoder.state_dict(), 'optimiser': self.optimiser.state_dict()}, os.path.join(self.model_path, 'models_%d.pth' % episode))
if episode % self.parms.storing_dataset_interval == 0:
self.D.store_dataset(self.parms.dataset_path+'dump_dataset')
return self.metrics
def test_model(self, episode=None): #no explore here
if episode is None:
episode = self.tested_episodes
# Set models to eval mode
self.transition_model.eval()
self.observation_model.eval()
self.reward_model.eval()
self.encoder.eval()
# Initialise parallelised test environments
test_envs = EnvBatcher(ControlSuiteEnv, (self.parms.env_name, self.parms.seed, self.parms.max_episode_length, self.parms.bit_depth), {}, self.parms.test_episodes)
total_steps = self.parms.max_episode_length // test_envs.action_repeat
rewards = np.zeros(self.parms.test_episodes)
real_rew = torch.zeros([total_steps,self.parms.test_episodes])
predicted_rew = torch.zeros([total_steps,self.parms.test_episodes])
with torch.no_grad():
observation, total_rewards, video_frames = test_envs.reset(), np.zeros((self.parms.test_episodes, )), []
belief, posterior_state, action = torch.zeros(self.parms.test_episodes, self.parms.belief_size, device=self.parms.device), torch.zeros(self.parms.test_episodes, self.parms.state_size, device=self.parms.device), torch.zeros(self.parms.test_episodes, self.env.action_size, device=self.parms.device)
tqdm.write("Testing model.")
for t in range(total_steps):
belief, posterior_state, action, next_observation, rewards, done, pred_next_rew = self.update_belief_and_act(test_envs, belief, posterior_state, action, observation.to(device=self.parms.device), list(rewards), self.env.action_range[0], self.env.action_range[1])
total_rewards += rewards.numpy()
real_rew[t] = rewards
predicted_rew[t] = pred_next_rew
observation = self.env.get_original_frame().unsqueeze(dim=0)
video_frames.append(make_grid(torch.cat([observation, self.observation_model(belief, posterior_state).cpu()], dim=3) + 0.5, nrow=5).numpy()) # Decentre
observation = next_observation
if done.sum().item() == self.parms.test_episodes:
break
real_rew = torch.transpose(real_rew, 0, 1)
predicted_rew = torch.transpose(predicted_rew, 0, 1)
#save and plot metrics
self.tested_episodes += 1
self.metrics['test_episodes'].append(episode)
self.metrics['test_rewards'].append(total_rewards.tolist())
lineplot(self.metrics['test_episodes'], self.metrics['test_rewards'], 'test_rewards', self.statistics_path)
write_video(video_frames, 'test_episode_%s' % str(episode), self.video_path) # Lossy compression
# Set models to train mode
self.transition_model.train()
self.observation_model.train()
self.reward_model.train()
self.encoder.train()
# Close test environments
test_envs.close()
return self.metrics
def dump_plan_video(self, step_before_plan=120):
#number of steps before to start to collect frames to dump
step_before_plan = min(step_before_plan, (self.parms.max_episode_length // self.env.action_repeat))
# Set models to eval mode
self.transition_model.eval()
self.observation_model.eval()
self.reward_model.eval()
self.encoder.eval()
video_frames = []
reward = 0
with torch.no_grad():
observation = self.env.reset()
belief, posterior_state, action = torch.zeros(1, self.parms.belief_size, device=self.parms.device), torch.zeros(1, self.parms.state_size, device=self.parms.device), torch.zeros(1, self.env.action_size, device=self.parms.device)
tqdm.write("Executing episode.")
for t in range(step_before_plan): #floor division
belief, posterior_state, action, next_observation, reward, done, _ = self.update_belief_and_act(self.env, belief, posterior_state, action, observation.to(device=self.parms.device), [reward], self.env.action_range[0], self.env.action_range[1])
observation = next_observation
video_frames.append(make_grid(torch.cat([observation.cpu(), self.observation_model(belief, posterior_state).to(device=self.parms.device).cpu()], dim=3) + 0.5, nrow=5).numpy()) # Decentre
if done:
break
self.create_and_dump_plan(self.env, belief, posterior_state, action, observation.to(device=self.parms.device), [reward], self.env.action_range[0], self.env.action_range[1])
# Set models to train mode
self.transition_model.train()
self.observation_model.train()
self.reward_model.train()
self.encoder.train()
# Close test environments
self.env.close()
def create_and_dump_plan(self, env, belief, posterior_state, action, observation, reward, min_action=-inf, max_action=inf):
tqdm.write("Dumping plan")
video_frames = []
encoded_obs = self.encoder(observation).unsqueeze(dim=0)
belief, _, _, _, posterior_state, _, _ = self.transition_model(posterior_state, action.unsqueeze(dim=0), belief, encoded_obs)
belief, posterior_state = belief.squeeze(dim=0), posterior_state.squeeze(dim=0) # Remove time dimension from belief/state
next_action,_, beliefs, states, plan = self.planner(belief, posterior_state,False) # Get action from planner(q(s_t|o≤t,a<t), p)
predicted_frames = self.observation_model(beliefs, states).to(device=self.parms.device)
for i in range(self.parms.planning_horizon):
plan[i].clamp_(min=env.action_range[0], max=self.env.action_range[1]) # Clip action range
next_observation, reward, done = env.step(plan[i].cpu())
next_observation = next_observation.squeeze(dim=0)
video_frames.append(make_grid(torch.cat([next_observation, predicted_frames[i]], dim=1) + 0.5, nrow=2).numpy()) # Decentre
write_video(video_frames, 'dump_plan', self.dump_plan_path, dump_frame=True)