mirror of
https://github.com/wassname/pytorch-a2c-ppo-acktr.git
synced 2026-06-27 16:20:05 +08:00
Ilya Kostrikov
257 lines
10 KiB
Python
Executable File
257 lines
10 KiB
Python
Executable File
import glob
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import os
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import gym
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import numpy as np
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import torch
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import torch.nn as nn
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import torch.nn.functional as F
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import torch.optim as optim
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from torch.autograd import Variable
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from torch.utils.data.sampler import BatchSampler, SubsetRandomSampler
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from arguments import get_args
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from baselines.common.vec_env.subproc_vec_env import SubprocVecEnv
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from envs import make_env
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from kfac import KFACOptimizer
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from model import ActorCritic
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from vizualize_atari import visdom_plot
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args = get_args()
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assert args.algo in ['a2c', 'ppo', 'acktr']
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if args.algo == 'ppo':
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assert args.num_processes * args.num_steps % args.batch_size == 0
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num_updates = int(args.num_frames) // args.num_steps // args.num_processes
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torch.manual_seed(args.seed)
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if args.cuda:
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torch.cuda.manual_seed(args.seed)
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try:
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os.makedirs(args.log_dir)
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except OSError:
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files = glob.glob(os.path.join(args.log_dir, '*.monitor.json'))
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for f in files:
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os.remove(f)
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def main():
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print("#######")
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print("WARNING: All rewards are clipped so you need to use a monitor (see envs.py) or visdom plot to get true rewards")
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print("#######")
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os.environ['OMP_NUM_THREADS'] = '1'
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if args.vis:
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from visdom import Visdom
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viz = Visdom()
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win = None
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envs = SubprocVecEnv([
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make_env(args.env_name, args.seed, i, args.log_dir)
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for i in range(args.num_processes)
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])
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actor_critic = ActorCritic(envs.observation_space.shape[0] * args.num_stack, envs.action_space)
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if args.algo == 'ppo':
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actor_critic = nn.DataParallel(actor_critic)
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if args.cuda:
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actor_critic.cuda()
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if args.algo == 'a2c':
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optimizer = optim.RMSprop(actor_critic.parameters(), args.lr, eps=args.eps, alpha=args.alpha)
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elif args.algo == 'ppo':
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optimizer = optim.Adam(actor_critic.parameters(), eps=args.eps)
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elif args.algo == 'acktr':
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optimizer = KFACOptimizer(actor_critic)
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obs_shape = envs.observation_space.shape
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obs_shape = (obs_shape[0] * args.num_stack, obs_shape[1], obs_shape[2])
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states = torch.zeros(args.num_steps + 1, args.num_processes, *obs_shape)
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current_state = torch.zeros(args.num_processes, *obs_shape)
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counts = 0
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def update_current_state(state):
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state = torch.from_numpy(np.stack(state)).float()
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current_state[:, :-1] = current_state[:, 1:]
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current_state[:, -1] = state
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state = envs.reset()
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update_current_state(state)
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rewards = torch.zeros(args.num_steps, args.num_processes, 1)
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value_preds = torch.zeros(args.num_steps + 1, args.num_processes, 1)
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old_log_probs = torch.zeros(args.num_steps, args.num_processes, envs.action_space.n)
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returns = torch.zeros(args.num_steps + 1, args.num_processes, 1)
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actions = torch.LongTensor(args.num_steps, args.num_processes)
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masks = torch.zeros(args.num_steps, args.num_processes, 1)
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# These variables are used to compute average rewards for all processes.
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episode_rewards = torch.zeros([args.num_processes, 1])
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final_rewards = torch.zeros([args.num_processes, 1])
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if args.cuda:
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states = states.cuda()
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current_state = current_state.cuda()
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rewards = rewards.cuda()
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value_preds = value_preds.cuda()
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old_log_probs = old_log_probs.cuda()
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returns = returns.cuda()
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actions = actions.cuda()
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masks = masks.cuda()
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for j in range(num_updates):
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for step in range(args.num_steps):
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# Sample actions
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value, logits = actor_critic(Variable(states[step], volatile=True))
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probs = F.softmax(logits)
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log_probs = F.log_softmax(logits).data
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actions[step] = probs.multinomial().data
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cpu_actions = actions[step].cpu()
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cpu_actions = cpu_actions.numpy()
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# Obser reward and next state
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state, reward, done, info = envs.step(cpu_actions)
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reward = torch.from_numpy(np.expand_dims(np.stack(reward), 1)).float()
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episode_rewards += reward
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np_masks = np.array([0.0 if done_ else 1.0 for done_ in done])
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# If done then clean the history of observations.
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pt_masks = torch.from_numpy(np_masks.reshape(np_masks.shape[0], 1, 1, 1)).float()
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if args.cuda:
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pt_masks = pt_masks.cuda()
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current_state *= pt_masks
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update_current_state(state)
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states[step + 1].copy_(current_state)
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value_preds[step].copy_(value.data)
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old_log_probs[step].copy_(log_probs)
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rewards[step].copy_(reward)
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masks[step].copy_(torch.from_numpy(np_masks).unsqueeze(1))
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final_rewards *= masks[step].cpu()
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final_rewards += (1 - masks[step].cpu()) * episode_rewards
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episode_rewards *= masks[step].cpu()
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if args.use_gae:
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value_preds[-1] = actor_critic(Variable(states[-1], volatile=True))[0].data
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gae = 0
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for step in reversed(range(args.num_steps)):
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delta = rewards[step] + args.gamma * value_preds[step + 1] * masks[step] - value_preds[step]
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gae = delta + args.gamma * args.tau * masks[step] * gae
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returns[step] = gae + value_preds[step]
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else:
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returns[-1] = actor_critic(Variable(states[-1], volatile=True))[0].data
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for step in reversed(range(args.num_steps)):
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returns[step] = returns[step + 1] * \
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args.gamma * masks[step] + rewards[step]
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if args.algo in ['a2c', 'acktr']:
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# Reshape to do in a single forward pass for all steps
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values, logits = actor_critic(Variable(states[:-1].view(-1, *states.size()[-3:])))
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log_probs = F.log_softmax(logits)
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# Unreshape
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logits_size = (args.num_steps, args.num_processes, logits.size(-1))
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log_probs = F.log_softmax(logits).view(logits_size)
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probs = F.softmax(logits).view(logits_size)
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values = values.view(args.num_steps, args.num_processes, 1)
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logits = logits.view(logits_size)
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action_log_probs = log_probs.gather(2, Variable(actions.unsqueeze(2)))
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dist_entropy = -(log_probs * probs).sum(-1).mean()
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advantages = Variable(returns[:-1]) - values
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value_loss = advantages.pow(2).mean()
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action_loss = -(Variable(advantages.data) * action_log_probs).mean()
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if args.algo == 'acktr' and optimizer.steps % optimizer.Ts == 0:
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# Sampled fisher, see Martens 2014
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actor_critic.zero_grad()
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pg_fisher_loss = -action_log_probs.mean()
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value_noise = Variable(torch.randn(values[:-1].size()))
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if args.cuda:
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value_noise = value_noise.cuda()
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sample_values = values[:-1] + value_noise
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vf_fisher_loss = - (values[:-1] - Variable(sample_values.data)).pow(2).mean()
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fisher_loss = pg_fisher_loss + vf_fisher_loss
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optimizer.acc_stats = True
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fisher_loss.backward(retain_graph=True)
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optimizer.acc_stats = False
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optimizer.zero_grad()
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(value_loss * args.value_loss_coef + action_loss - dist_entropy * args.entropy_coef).backward()
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if args.algo == 'a2c':
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nn.utils.clip_grad_norm(actor_critic.parameters(), args.max_grad_norm)
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optimizer.step()
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elif args.algo == 'ppo':
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advantages = returns[:-1] - value_preds[:-1]
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advantages = (advantages - advantages.mean()) / advantages.std()
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for _ in range(args.ppo_epoch):
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sampler = BatchSampler(SubsetRandomSampler(range(args.num_processes * args.num_steps)), args.batch_size * args.num_processes, drop_last=False)
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for indices in sampler:
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states_batch = states[:-1].view(-1, *states.size()[-3:])[indices]
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actions_batch = actions.view(-1, 1)[indices]
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return_batch = returns[:-1].view(-1, 1)[indices]
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# Reshape to do in a single forward pass for all steps
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values, logits = actor_critic(Variable(states_batch))
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log_probs = F.log_softmax(logits)
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action_log_probs = log_probs.gather(1, Variable(actions_batch))
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old_log_probs_batch = old_log_probs.view(-1, old_log_probs.size(-1))[indices]
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old_action_log_probs = old_log_probs_batch.gather(1, actions_batch)
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ratio = torch.exp(action_log_probs - Variable(old_action_log_probs))
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adv_targ = Variable(advantages.view(-1, 1)[indices])
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surr1 = ratio * adv_targ
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surr2 = ratio.clamp(1.0 - args.clip_param, 1.0 + args.clip_param) * adv_targ
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action_loss = -torch.min(surr1, surr2).mean() # PPO's pessimistic surrogate (L^CLIP)
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log_probs = F.log_softmax(logits)
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probs = F.softmax(logits)
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dist_entropy = -(log_probs * probs).sum(-1).mean()
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value_loss = (Variable(return_batch) - values).pow(2).mean()
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optimizer.zero_grad()
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(value_loss + action_loss - dist_entropy * args.entropy_coef).backward()
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optimizer.step()
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states[0].copy_(states[-1])
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if j % args.log_interval == 0:
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print("Updates {}, num frames {}, mean/median reward {:.1f}/{:.1f}, min/max reward {:.1f}/{:.1f}, entropy {:.5f}, value loss {:.5f}, policy loss {:.5f}".
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format(j, j * args.num_processes * args.num_steps,
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final_rewards.mean(),
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final_rewards.median(),
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final_rewards.min(),
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final_rewards.max(), -dist_entropy.data[0],
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value_loss.data[0], action_loss.data[0]))
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if j % args.vis_interval == 0:
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win = visdom_plot(viz, win, args.log_dir, args.env_name, args.algo)
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if __name__ == "__main__":
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main()
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