class Agent: def __init__( self, env: 'Environment', input_frame: ('int: the number of channels of input image'), input_dim: ( 'int: the width and height of pre-processed input image'), num_frames: ('int: Total number of frames'), eps_decay: ('float: Epsilon Decay_rate'), gamma: ('float: Discount Factor'), target_update_freq: ('int: Target Update Frequency (by frames)'), update_type: ( 'str: Update type for target network. Hard or Soft') = 'hard', soft_update_tau: ('float: Soft update ratio') = None, batch_size: ('int: Update batch size') = 32, buffer_size: ('int: Replay buffer size') = 1000000, update_start_buffer_size: ( 'int: Update starting buffer size') = 50000, learning_rate: ('float: Learning rate') = 0.0004, eps_min: ('float: Epsilon Min') = 0.1, eps_max: ('float: Epsilon Max') = 1.0, device_num: ('int: GPU device number') = 0, rand_seed: ('int: Random seed') = None, plot_option: ('str: Plotting option') = False, model_path: ('str: Model saving path') = './'): self.action_dim = env.action_space.n self.device = torch.device( f'cuda:{device_num}' if torch.cuda.is_available() else 'cpu') self.model_path = model_path self.env = env self.input_frames = input_frame self.input_dim = input_dim self.num_frames = num_frames self.epsilon = eps_max self.eps_decay = eps_decay self.eps_min = eps_min self.gamma = gamma self.target_update_freq = target_update_freq self.update_cnt = 0 self.update_type = update_type self.tau = soft_update_tau self.batch_size = batch_size self.buffer_size = buffer_size self.update_start = update_start_buffer_size self.seed = rand_seed self.plot_option = plot_option self.q_current = QNetwork( (self.input_frames, self.input_dim, self.input_dim), self.action_dim).to(self.device) self.q_target = QNetwork( (self.input_frames, self.input_dim, self.input_dim), self.action_dim).to(self.device) self.q_target.load_state_dict(self.q_current.state_dict()) self.q_target.eval() self.optimizer = optim.Adam(self.q_current.parameters(), lr=learning_rate) self.memory = ReplayBuffer( self.buffer_size, (self.input_frames, self.input_dim, self.input_dim), self.batch_size) def select_action( self, state: 'Must be pre-processed in the same way while updating current Q network. See def _compute_loss' ): if np.random.random() < self.epsilon: return np.zeros(self.action_dim), self.env.action_space.sample() else: # if normalization is applied to the image such as devision by 255, MUST be expressed 'state/255' below. state = torch.FloatTensor(state).to(self.device).unsqueeze(0) / 255 Qs = self.q_current(state) action = Qs.argmax() return Qs.detach().cpu().numpy(), action.detach().item() def processing_resize_and_gray(self, frame): frame = cv2.cvtColor(frame, cv2.COLOR_RGB2GRAY) # Pure # frame = cv2.cvtColor(frame[:177, 32:128, :], cv2.COLOR_RGB2GRAY) # Boxing # frame = cv2.cvtColor(frame[2:198, 7:-7, :], cv2.COLOR_RGB2GRAY) # Breakout frame = cv2.resize(frame, dsize=(self.input_dim, self.input_dim)).reshape( self.input_dim, self.input_dim).astype(np.uint8) return frame def get_state(self, action, skipped_frame=0): ''' num_frames: how many frames to be merged input_size: hight and width of input resized image skipped_frame: how many frames to be skipped ''' next_state = np.zeros( (self.input_frames, self.input_dim, self.input_dim)) rewards = 0 dones = 0 for i in range(self.input_frames): for j in range(skipped_frame): state, reward, done, _ = self.env.step(action) rewards += reward dones += int(done) state, reward, done, _ = self.env.step(action) next_state[i] = self.processing_resize_and_gray(state) rewards += reward dones += int(done) return rewards, next_state, dones def get_init_state(self): state = self.env.reset() action = self.env.action_space.sample() _, state, _ = self.get_state(action, skipped_frame=0) return state def store(self, state, action, reward, next_state, done): self.memory.store(state, action, reward, next_state, done) def update_current_q_net(self): batch = self.memory.batch_load() loss = self._compute_loss(batch) self.optimizer.zero_grad() loss.backward() self.optimizer.step() return loss.item() def target_soft_update(self): for target_param, current_param in zip(self.q_target.parameters(), self.q_current.parameters()): target_param.data.copy_(self.tau * current_param.data + (1.0 - self.tau) * target_param.data) def target_hard_update(self): self.update_cnt = (self.update_cnt + 1) % self.target_update_freq if self.update_cnt == 0: self.q_target.load_state_dict(self.q_current.state_dict()) def train(self): tic = time.time() losses = [] scores = [] epsilons = [] avg_scores = [[-1000]] score = 0 print("Storing initial buffer..") state = self.get_init_state() for frame_idx in range(1, self.update_start + 1): _, action = self.select_action(state) reward, next_state, done = self.get_state(action, skipped_frame=0) self.store(state, action, reward, next_state, done) state = next_state if done: state = self.get_init_state() print("Done. Start learning..") history_store = [] for frame_idx in range(1, self.num_frames + 1): Qs, action = self.select_action(state) reward, next_state, done = self.get_state(action, skipped_frame=0) self.store(state, action, reward, next_state, done) history_store.append([state, Qs, action, reward, next_state, done]) loss = self.update_current_q_net() if self.update_type == 'hard': self.target_hard_update() elif self.update_type == 'soft': self.target_soft_update() score += reward losses.append(loss) if done: scores.append(score) if np.mean(scores[-10:]) > max(avg_scores): torch.save( self.q_current.state_dict(), self.model_path + '{}_Score:{}.pt'.format( frame_idx, np.mean(scores[-10:]))) training_time = round((time.time() - tic) / 3600, 1) np.save( self.model_path + '{}_history_Score_{}_{}hrs.npy'.format( frame_idx, score, training_time), np.array(history_store)) print( " | Model saved. Recent scores: {}, Training time: {}hrs" .format(scores[-10:], training_time), ' /'.join(os.getcwd().split('/')[-3:])) avg_scores.append(np.mean(scores[-10:])) if self.plot_option == 'inline': scores.append(score) epsilons.append(self.epsilon) self._plot(frame_idx, scores, losses, epsilons) elif self.plot_option == 'wandb': wandb.log({ 'Score': score, 'loss(10 frames avg)': np.mean(losses[-10:]), 'Epsilon': self.epsilon }) print(score, end='\r') else: print(score, end='\r') score = 0 state = self.get_init_state() history_store = [] else: state = next_state self._epsilon_step() print("Total training time: {}(hrs)".format( (time.time() - tic) / 3600)) def _epsilon_step(self): ''' Epsilon decay control ''' eps_decay_init = 1 / 1200000 eps_decay = [ eps_decay_init, eps_decay_init / 2.5, eps_decay_init / 3.5, eps_decay_init / 5.5 ] if self.epsilon > 0.35: self.epsilon = max(self.epsilon - eps_decay[0], 0.1) elif self.epsilon > 0.27: self.epsilon = max(self.epsilon - eps_decay[1], 0.1) elif self.epsilon > 1.7: self.epsilon = max(self.epsilon - eps_decay[2], 0.1) else: self.epsilon = max(self.epsilon - eps_decay[3], 0.1) def _compute_loss(self, batch: "Dictionary (S, A, R', S', Dones)"): # If normalization is used, it must be applied to 'state' and 'next_state' here. ex) state/255 states = torch.FloatTensor(batch['states']).to(self.device) / 255 next_states = torch.FloatTensor(batch['next_states']).to( self.device) / 255 actions = torch.LongTensor(batch['actions'].reshape(-1, 1)).to(self.device) rewards = torch.FloatTensor(batch['rewards'].reshape(-1, 1)).to( self.device) dones = torch.FloatTensor(batch['dones'].reshape(-1, 1)).to(self.device) current_q = self.q_current(states).gather(1, actions) # The next line is the only difference from Vanila DQN. next_q = self.q_target(next_states).gather( 1, self.q_current(next_states).argmax(axis=1, keepdim=True)).detach() mask = 1 - dones target = (rewards + (mask * self.gamma * next_q)).to(self.device) loss = F.smooth_l1_loss(current_q, target) return loss def _plot(self, frame_idx, scores, losses, epsilons): clear_output(True) plt.figure(figsize=(20, 5), facecolor='w') plt.subplot(131) plt.title('frame %s. score: %s' % (frame_idx, np.mean(scores[-10:]))) plt.plot(scores) plt.subplot(132) plt.title('loss') plt.plot(losses) plt.subplot(133) plt.title('epsilons') plt.plot(epsilons) plt.show()
class Agent(): """Interacts with and learns from the environment.""" def __init__(self, state_size, action_size, seed): """Initialize an Agent object. Params ====== state_size (int): dimension of each state action_size (int): dimension of each action seed (int): random seed """ self.state_size = state_size self.action_size = action_size self.seed = random.seed(seed) # Q-Network self.qnetwork_local = QNetwork(state_size, action_size, seed).to(device) self.qnetwork_target = QNetwork(state_size, action_size, seed).to(device) self.optimizer = optim.Adam(self.qnetwork_local.parameters(), lr=LR) # Replay memory self.memory = ReplayBuffer(action_size, BUFFER_SIZE, BATCH_SIZE, seed) # Initialize time step (for updating every UPDATE_EVERY steps) self.t_step = 0 def step(self, state, action, reward, next_state, done): # Save experience in replay memory self.memory.add(state, action, reward, next_state, done) # Learn every UPDATE_EVERY time steps. self.t_step = (self.t_step + 1) % UPDATE_EVERY if self.t_step == 0: # If enough samples are available in memory, get random subset and learn if len(self.memory) > BATCH_SIZE: experiences = self.memory.sample() self.learn(experiences, GAMMA) def act(self, state, eps=0.0, training_mode=True): """Returns actions for given state as per current policy. Params ====== state (array_like): current state eps (float): epsilon, for epsilon-greedy action selection """ state = torch.from_numpy(state).float().unsqueeze(0).to(device) self.qnetwork_local.eval() with torch.no_grad(): action_values = self.qnetwork_local(state) if training_mode is True: self.qnetwork_local.train() # Epsilon-greedy action selection if random.random() > eps: action = np.argmax(action_values.cpu().data.numpy()) else: action = random.choice(np.arange(self.action_size)) action = np.int32(action) return action def learn(self, experiences, gamma): """Update value parameters using given batch of experience tuples. Params ====== experiences (Tuple[torch.Variable]): tuple of (s, a, r, s', done) tuples gamma (float): discount factor """ states, actions, rewards, next_states, dones = experiences # Get max predicted Q values (for next states) from target model Q_targets_next = self.qnetwork_target(next_states).detach().max( 1)[0].unsqueeze(1) # Compute Q targets for current states Q_targets = rewards + (gamma * Q_targets_next * (1 - dones)) # Get expected Q values from local model Q_expected = self.qnetwork_local(states).gather(1, actions) # Compute loss loss = F.mse_loss(Q_expected, Q_targets) # Minimize the loss self.optimizer.zero_grad() loss.backward() self.optimizer.step() # ------------------- update target network ------------------- # self.soft_update(self.qnetwork_local, self.qnetwork_target, TAU) def soft_update(self, local_model, target_model, tau): """Soft update model parameters. θ_target = τ*θ_local + (1 - τ)*θ_target Params ====== local_model (PyTorch model): weights will be copied from target_model (PyTorch model): weights will be copied to tau (float): interpolation parameter """ for target_param, local_param in zip(target_model.parameters(), local_model.parameters()): target_param.data.copy_(tau * local_param.data + (1.0 - tau) * target_param.data)
class DQN(object): def __init__(self,state_space,action_space,seed,update_every,batch_size,buffer_size,learning_rate): self.action_space = action_space self.state_space = state_space self.seed = random.seed(seed) self.batch_size = batch_size self.buffer_size = buffer_size self.learning_rate = learning_rate self.update_every = update_every self.qnetwork_local = QNetwork(state_space,action_space) self.qnetwork_target = QNetwork(state_space,action_space) self.optimizer = optim.Adam(self.qnetwork_local.parameters(),lr=learning_rate) # Initialize replaybuffer self.memory = ReplayBuffer(action_space,buffer_size,buffer_size,seed) # Initialize time step (for updating every UPDATE_EVERY steps) self.t_step = 0 def step(self,state,action,reward,next_state,done,GAMMA): # Save the experience self.memory.add_experience(state,action,reward,next_state,done) # learn from the experience self.t_step = (self.t_step + 1) % self.update_every if self.t_step == 0: if len(self.memory) > self.buffer_size: experiences = self.memory.sample() self.learn(experiences,GAMMA) def act(self,state,eps=0.): state = torch.from_numpy(state).float().unsqueeze(0).to(device) self.qnetwork_local.eval() with torch.no_grad(): action_values = self.qnetwork_local(state) self.qnetwork_local.train() if random.random() > eps: return np.argmax(action_values.cpu().data.numpy()) else: return random.sample(np.arange(self.action_space)) def learn(self,experiences,GAMMA): states,actions,rewards,next_states,dones = experiences target_values = self.qnetwork_target(next_states).detach().max(1)[0].unsqueeze(1) targets = reward + (GAMMA * target_values * (1-done)) action_values = self.qnetwork_local(states).gather(1,actions) loss = F.mse_loss(action_values,targets) loss.backward() self.optimizer.step() soft_update(TAU) def soft_update(self,tau): """Soft update model parameters. θ_target = τ*θ_local + (1 - τ)*θ_target """ for local_param,target_param in zip(self.qnetwork_local.parameters(),self.qnetwork_target.parameters()): local_param.data.copy_(tau*local_param.data + (1-tau)*target_param.data) # self.qnetwork_local.parameters() = TAU*self.qnetwork_local.parameters() + (1-TAU)*self.qnetwork_target.parameters()
class DQN_Agent(): """ Interacts an learns from the environment. """ def __init__(self, state_size, action_size, seed, GAMMA=GAMMA, TAU=TAU, LR=LR, UPDATE_EVERY=UPDATE_EVERY, BUFFER_SIZE=BUFFER_SIZE, BATCH_SIZE=BATCH_SIZE): """ Initialize the agent. ========== PARAMETERS ========== state_size (int) = observation dimension of the environment action_size (int) = dimension of each action seed (int) = random seed """ self.state_size = state_size self.action_size = action_size self.seed = random.seed(seed) self.gamma = GAMMA self.tau = TAU self.lr = LR self.update_every = UPDATE_EVERY self.buffer_size = BUFFER_SIZE self.batch_size = BATCH_SIZE self.device = torch.device( "cuda:0" if torch.cuda.is_available() else "cpu") # instantiate online local and target network for weight updates self.qnetwork_local = QNetwork(state_size, action_size, seed).to(self.device) self.qnetwork_target = QNetwork(state_size, action_size, seed).to(self.device) self.optimizer = optim.Adam(self.qnetwork_local.parameters(), lr=self.lr) # create a replay buffer self.memory = ReplayBuffer(action_size, self.buffer_size, self.batch_size, seed, self.device) # time steps for updating target network every time t_step % 4 == 0 self.t_step = 0 def step(self, state, action, reward, next_state, done): ''' Append a SARS sequence to memory, then every update_every steps learn from experiences''' self.memory.add(state, action, reward, next_state, done) self.t_step = (self.t_step + 1) % self.update_every if self.t_step == 0: # in case enough samples are available in internal memory, sample and learn if len(self.memory) > self.batch_size: experiences = self.memory.sample() self.learn(experiences, self.gamma) def act(self, state, eps=0.): """ Choose action from an epsilon-greedy policy ========== PARAMETERS ========== state (array) = current state space eps (float) = epsilon, for epsilon-greedy action choice """ state = torch.from_numpy(state).float().unsqueeze(0).to(self.device) self.qnetwork_local.eval() with torch.no_grad(): action_values = self.qnetwork_local.forward(state) self.qnetwork_local.train() if random.random() > eps: return np.argmax(action_values.cpu().data.numpy()) else: return random.choice(np.arange(self.action_size)) def learn(self, experiences, gamma): """ Update the value parameters using experience tuples sampled from ReplayBuffer ========== PARAMETERS ========== experiences = Tuple of torch.Variable: SARS', done gamma (float) = discount factor to weight rewards """ states, actions, rewards, next_states, dones = experiences # calculate max predicted Q values for the next states using target model Q_targets_next = self.qnetwork_target(next_states).detach().max( 1)[0].unsqueeze(1) Q_targets = rewards + (gamma * Q_targets_next * (1 - dones)) # calculate expected Q vaues from the local model Q_expected = self.qnetwork_local(states).gather(1, actions) # compute MSE Loss loss = F.mse_loss(Q_expected, Q_targets) self.optimizer.zero_grad() loss.backward() self.optimizer.step() self.soft_update(self.qnetwork_local, self.qnetwork_target, self.tau) def soft_update(self, local_model, target_model, tau): """ Soft update for model parameters, every update steps as defined above theta_target = tau * theta_local + (1-tau)*theta_target ========== PARAMETERS ========== local_model, target_model = PyTorch Models, weights will be copied from-to tau = interpolation parameter, type=float """ for target_param, local_param in zip(target_model.parameters(), local_model.parameters()): target_param.data.copy_(self.tau * local_param.data + (1.0 - self.tau) * target_param.data)