-
Notifications
You must be signed in to change notification settings - Fork 1
/
sac.py
129 lines (100 loc) · 6.01 KB
/
sac.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
import os
import torch
import torch.nn.functional as F
from torch.optim import Adam
from utils import soft_update, hard_update
from model import GaussianPolicy, QNetwork, DeterministicPolicy
class SAC(object):
def __init__(self, num_inputs, action_space, args):
self.gamma = args.gamma
self.tau = args.tau
self.alpha = args.alpha
self.policy_type = args.policy
self.target_update_interval = args.target_update_interval
self.automatic_entropy_tuning = args.automatic_entropy_tuning
# self.device = torch.device("cuda" if args.cuda else "cpu")
self.device = torch.device("cuda:"+ str(args.cuda) if args.cuda else "cpu")
# self.device = torch.device("cpu")
print(self.device)
self.critic = QNetwork(num_inputs, action_space.shape[0], args.hidden_size).to(device=self.device)
self.critic_optim = Adam(self.critic.parameters(), lr=args.lr)
self.critic_target = QNetwork(num_inputs, action_space.shape[0], args.hidden_size).to(self.device)
hard_update(self.critic_target, self.critic)
if self.policy_type == "Gaussian":
# Target Entropy = −dim(A) (e.g. , -6 for HalfCheetah-v2) as given in the paper
if self.automatic_entropy_tuning is True:
self.target_entropy = -torch.prod(torch.Tensor(action_space.shape).to(self.device)).item()
self.log_alpha = torch.zeros(1, requires_grad=True, device=self.device)
self.alpha_optim = Adam([self.log_alpha], lr=args.lr)
self.policy = GaussianPolicy(num_inputs, action_space.shape[0], args.hidden_size, action_space).to(self.device)
self.policy_optim = Adam(self.policy.parameters(), lr=args.lr)
else:
self.alpha = 0
self.automatic_entropy_tuning = False
self.policy = DeterministicPolicy(num_inputs, action_space.shape[0], args.hidden_size, action_space).to(self.device)
self.policy_optim = Adam(self.policy.parameters(), lr=args.lr)
def select_action(self, state, evaluate=False):
state = torch.FloatTensor(state).to(self.device).unsqueeze(0)
if evaluate is False:
action, _, _ = self.policy.sample(state)
else:
_, _, action = self.policy.sample(state)
return action.detach().cpu().numpy()[0]
def update_parameters(self, memory, batch_size, updates):
# Sample a batch from memory
state_batch, action_batch, reward_batch, next_state_batch, mask_batch = memory.sample(batch_size=batch_size)
state_batch = torch.FloatTensor(state_batch).to(self.device)
next_state_batch = torch.FloatTensor(next_state_batch).to(self.device)
action_batch = torch.FloatTensor(action_batch).to(self.device)
reward_batch = torch.FloatTensor(reward_batch).to(self.device).unsqueeze(1)
mask_batch = torch.FloatTensor(mask_batch).to(self.device).unsqueeze(1)
with torch.no_grad():
next_state_action, next_state_log_pi, _ = self.policy.sample(next_state_batch)
qf1_next_target, qf2_next_target = self.critic_target(next_state_batch, next_state_action)
min_qf_next_target = torch.min(qf1_next_target, qf2_next_target) - self.alpha * next_state_log_pi
next_q_value = reward_batch + mask_batch * self.gamma * (min_qf_next_target)
qf1, qf2 = self.critic(state_batch, action_batch) # Two Q-functions to mitigate positive bias in the policy improvement step
qf1_loss = F.mse_loss(qf1, next_q_value) # JQ = 𝔼(st,at)~D[0.5(Q1(st,at) - r(st,at) - γ(𝔼st+1~p[V(st+1)]))^2]
qf2_loss = F.mse_loss(qf2, next_q_value) # JQ = 𝔼(st,at)~D[0.5(Q1(st,at) - r(st,at) - γ(𝔼st+1~p[V(st+1)]))^2]
qf_loss = qf1_loss + qf2_loss
self.critic_optim.zero_grad()
qf_loss.backward()
self.critic_optim.step()
pi, log_pi, _ = self.policy.sample(state_batch)
qf1_pi, qf2_pi = self.critic(state_batch, pi)
min_qf_pi = torch.min(qf1_pi, qf2_pi)
policy_loss = ((self.alpha * log_pi) - min_qf_pi).mean() # Jπ = 𝔼st∼D,εt∼N[α * logπ(f(εt;st)|st) − Q(st,f(εt;st))]
self.policy_optim.zero_grad()
policy_loss.backward()
self.policy_optim.step()
if self.automatic_entropy_tuning:
alpha_loss = -(self.log_alpha * (log_pi + self.target_entropy).detach()).mean()
self.alpha_optim.zero_grad()
alpha_loss.backward()
self.alpha_optim.step()
self.alpha = self.log_alpha.exp()
alpha_tlogs = self.alpha.clone() # For TensorboardX logs
else:
alpha_loss = torch.tensor(0.).to(self.device)
alpha_tlogs = torch.tensor(self.alpha) # For TensorboardX logs
if updates % self.target_update_interval == 0:
soft_update(self.critic_target, self.critic, self.tau)
return qf1_loss.item(), qf2_loss.item(), policy_loss.item(), alpha_loss.item(), alpha_tlogs.item()
# Save model parameters
def save_model(self, env_name, suffix="", actor_path=None, critic_path=None):
if not os.path.exists('models/'):
os.makedirs('models/')
if actor_path is None:
actor_path = "models/sac_actor_{}_{}".format(env_name, suffix)
if critic_path is None:
critic_path = "models/sac_critic_{}_{}".format(env_name, suffix)
print('Saving models to {} and {}'.format(actor_path, critic_path))
torch.save(self.policy.state_dict(), actor_path)
torch.save(self.critic.state_dict(), critic_path)
# Load model parameters
def load_model(self, actor_path, critic_path):
print('Loading models from {} and {}'.format(actor_path, critic_path))
if actor_path is not None:
self.policy.load_state_dict(torch.load(actor_path))
if critic_path is not None:
self.critic.load_state_dict(torch.load(critic_path))