def __init__(self,
state_size,
action_size,
gamma=0.99,
lr=5e-4,
buffer_size=int(1e5),
batch_size=64,
tau=1e-3):
# defining local and target networks
self.qnet_local = Qnetwork(state_size, action_size).to(device)
self.qnet_target = Qnetwork(state_size, action_size).to(device)
# set local and target parameters equal to each other
self.soft_update(tau=1.0)
# experience replay buffer
self.memory = ReplayBuffer(buffer_size, batch_size)
# defining variables
self.state_size = state_size
self.action_size = action_size
self.buffer_size = buffer_size
self.batch_size = batch_size
self.gamma = gamma
self.lr = lr
self.tau = tau
self.t_step = 0
# optimizer
self.optimizer = optim.Adam(self.qnet_local.parameters(), lr=self.lr)
def __init__(self, state_size, action_size):
self.state_size = state_size
self.action_size = action_size
self.Qlocal = Qnetwork(self.state_size,
self.action_size).to(device) # Local Network
self.Qtarget = Qnetwork(self.state_size,
self.action_size).to(device) # Taget Network
self.optim = optim.Adam(self.Qlocal.parameters(), lr)
self.buffer = replay_buffer(buffer_max_size,
batch_size) # replay buffer
self.t_step = 0 # used in updating the target network weights from local network
def __init__(self, state_size, action_size, seed):
self.state_size = state_size
self.action_size = action_size
#self.device=device
self.seed = random.seed(seed)
self.q_network_local = Qnetwork(state_size, action_size,
seed).to(device)
self.q_network_target = Qnetwork(state_size, action_size,
seed).to(device)
self.optimizer = optim.Adam(self.q_network_local.parameters(), lr=LR)
####REPLAY MEMORY########
self.memory = ReplayBuffer(action_size, BUFFER_SIZE, BATCH_SIZE, seed)
self.t_step = 0
def __init__(self, seed, state_size, action_size, net_type="dqn"):
"""if net_type is dqn, perform deep Q network; if ddqn, perform double deep Q network"""
self.state_size = state_size
self.action_size = action_size
self.seed = random.seed(seed)
self.net_type = net_type
# replay buffer
self.memory = replaybuffer(action_size, BATCH_SIZE, seed)
# define target and local Q network
self.qnetwork_local = Qnetwork(state_size, action_size,
seed).to(device)
self.qnetwork_target = Qnetwork(state_size, action_size,
seed).to(device)
# define optimizer for qnetwork_local
self.optim = optim.Adam(self.qnetwork_local.parameters(), lr=LR)
# define time step for soft updating cycle
self.time_step = 0
def __init__(self, state_size, action_size):
"""Initialize an Agent object.
Params
======
state_size (int): dimension of each state
action_size (int): dimension of each action
"""
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).to(device)
self.qnetwork_target = Qnetwork(state_size, action_size).to(device)
self.optimizer = optim.Adam(self.qnetwork_local.parameters(), lr=LR)
# Replay memory
self.memory = ReplayBuffer(action_size, BUFFER_SIZE, BATCH_SIZE)
# Initialize time step (for updating every UPDATE_EVERY steps)
self.t_step = 0
def __init__(self, state_size, action_size, double=False, duel=False):
self.state_size = state_size
self.action_size = action_size
self.discounted_factor = 0.99
self.learning_rate = 0.001
self.double = double
# Define Model
if duel:
self.local_model = Duel_Qnetwork(state_size,
action_size).to(device)
self.target_model = Duel_Qnetwork(state_size,
action_size).to(device)
else:
self.local_model = Qnetwork(state_size, action_size).to(device)
self.target_model = Qnetwork(state_size, action_size).to(device)
# Define optimizer
self.optimizer = optim.Adam(self.local_model.parameters(),
lr=self.learning_rate)
# Define Buffer
self.buffer = Replay_buffer(action_size,
buffer_size=BUFFER_SIZE,
batch_size=BATCH_SIZE)
# time_step, local_model update, target_model update
self.t_step = 0
self.target_update_t = 0
def __init__(self, state_size, action_size, seed):
"""Initialize an Agent
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)
#Qnetwork
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)
#init time step
self.t_step = 0
class smart_agent():
def __init__(self, state_size, action_size, seed):
self.state_size = state_size
self.action_size = action_size
#self.device=device
self.seed = random.seed(seed)
self.q_network_local = Qnetwork(state_size, action_size,
seed).to(device)
self.q_network_target = Qnetwork(state_size, action_size,
seed).to(device)
self.optimizer = optim.Adam(self.q_network_local.parameters(), lr=LR)
####REPLAY MEMORY########
self.memory = ReplayBuffer(action_size, BUFFER_SIZE, BATCH_SIZE, seed)
self.t_step = 0
def step(self, state, action, reward, next_state, done):
self.memory.add(state, action, reward, next_state, done)
self.t_step = (self.t_step + 1) % UPDATE_EVERY
if self.t_step == 0:
if len(self.memory) > BATCH_SIZE:
xp = self.memory.sample()
self.learn(xp, GAMMA)
def act(self, state, eps=0.):
state = torch.from_numpy(state).float().unsqueeze(0).to(device)
self.q_network_local.eval()
with torch.no_grad():
action_value = self.q_network_local(state)
self.q_network_local.train()
#Epsilon greedy selection
if random.random() > eps:
return np.argmax(action_value.cpu().data.numpy())
else:
return random.choice(np.arange(self.action_size))
def learn(self, xp, gamma):
state, action, reward, next_state, done = xp
q_target_next = self.q_network_target(next_state).detach().max(
1)[0].unsqueeze(1)
q_target = reward + (gamma * q_target_next * (1 - done))
q_expected = self.q_network_local(state).gather(1, action)
#MSE LOSS
loss = F.mse_loss(q_expected, q_target)
self.optimizer.zero_grad()
loss.backward()
self.optimizer.step()
self.soft_update(self.q_network_local, self.q_network_target, TAU)
def soft_update(self, local_model, target_model, tau):
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 Agent:
def __init__(self, seed, state_size, action_size, net_type="dqn"):
"""if net_type is dqn, perform deep Q network; if ddqn, perform double deep Q network"""
self.state_size = state_size
self.action_size = action_size
self.seed = random.seed(seed)
self.net_type = net_type
# replay buffer
self.memory = replaybuffer(action_size, BATCH_SIZE, seed)
# define target and local Q network
self.qnetwork_local = Qnetwork(state_size, action_size,
seed).to(device)
self.qnetwork_target = Qnetwork(state_size, action_size,
seed).to(device)
# define optimizer for qnetwork_local
self.optim = optim.Adam(self.qnetwork_local.parameters(), lr=LR)
# define time step for soft updating cycle
self.time_step = 0
def collect(self, state, action, reward, next_state, done):
# collect the new sample
self.memory.add(state, action, reward, next_state, done)
# use time step to decide if it needs to learn or not
self.time_step = (self.time_step + 1) % UPDATE_EVERY
if self.time_step == 0:
if len(self.memory) >= BATCH_SIZE:
experiences = self.memory.sample()
self.learn(experiences, ALPHA)
def act(self, state):
state = torch.from_numpy(state).unsqueeze(0).float().to(device)
# get action_values
self.qnetwork_local.eval()
with torch.no_grad():
action_vals = self.qnetwork_local(state)
self.qnetwork_local.train()
# use epsilon_greedy policies to decide which action to take
policy = np.ones(self.action_size) * (EPSILON / self.action_size)
best = torch.argmax(action_vals).item()
policy[best] = 1 - EPSILON + (EPSILON / self.action_size)
return np.random.choice(np.arange(self.action_size), p=policy)
def learn(self, experiences, alpha):
states, actions, rewards, next_states, dones = experiences
# parameter learning for local network
if self.net_type == "dqn":
TD_target = rewards + GAMMA * (self.qnetwork_target(
next_states).detach().max(1)[0].unsqueeze(1)) * (1 - dones)
if self.net_type == "ddqn":
best = self.qnetwork_local(next_states).detach().max(
1)[1].unsqueeze(1)
TD_target = rewards + GAMMA * (
self.qnetwork_target(next_states).detach().gather(1, best))
TD_estimate = self.qnetwork_local(states).gather(1, actions)
loss = F.mse_loss(TD_target, TD_estimate)
self.optim.zero_grad()
loss.backward()
self.optim.step()
# parameter soft updating for target network
self.soft_update(self.qnetwork_local, self.qnetwork_target, alpha)
def soft_update(self, local_network, target_network, alpha):
for local_params, target_params in zip(local_network.parameters(),
target_network.parameters()):
target_params.data.copy_(alpha * local_params.data +
(1 - alpha) * target_params.data)
class agent():
def __init__(self, state_size, action_size, seed):
"""Initialize an Agent
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)
#Qnetwork
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)
#init time step
self.t_step = 0
def step(self, state, action, reward, next_state, done):
#save step to replay memory
self.memory.add(state, action, reward, next_state, done)
#learn every update_every t_steps
self.t_step = (self.t_step + 1) % update_every
if self.t_step == 0:
#check if enough samples are in memory if there are then learn
if len(self.memory) > batch_size:
exps = self.memory.sample()
self.learn(exps, gamma)
def act(self, state, eps=0.):
'''Returns actions for a given state based on the 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)
self.Qnetwork_local.train()
#epsilon-greedy action selection
if random.random() > eps:
return np.argmax(action_values.cpu().data.numpy())
else:
return random.choice(np.arange(self.action_size))
def learn(self, exps, gamma):
"""Update value parameters using a 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, done = exps
#get max predicted Q values for next state 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 - done))
#calculate 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 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 DQNAgent():
def __init__(self, state_size, action_size, double=False, duel=False):
self.state_size = state_size
self.action_size = action_size
self.discounted_factor = 0.99
self.learning_rate = 0.001
self.double = double
# Define Model
if duel:
self.local_model = Duel_Qnetwork(state_size,
action_size).to(device)
self.target_model = Duel_Qnetwork(state_size,
action_size).to(device)
else:
self.local_model = Qnetwork(state_size, action_size).to(device)
self.target_model = Qnetwork(state_size, action_size).to(device)
# Define optimizer
self.optimizer = optim.Adam(self.local_model.parameters(),
lr=self.learning_rate)
# Define Buffer
self.buffer = Replay_buffer(action_size,
buffer_size=BUFFER_SIZE,
batch_size=BATCH_SIZE)
# time_step, local_model update, target_model update
self.t_step = 0
self.target_update_t = 0
def get_action(self, state, eps=0.0):
"""state (numpy.ndarray)"""
state = torch.from_numpy(state.reshape(
1, self.state_size)).float().to(device)
self.local_model.eval()
with torch.no_grad():
action_values = self.local_model(state) # .detach().cpu()
self.local_model.train()
# epsilon greedy policy
if random.random() < eps:
action = np.random.randint(4)
return action
else:
action = np.argmax(action_values.cpu().data.numpy())
return int(action)
def append_sample(self, state, action, reward, next_state, done):
self.buffer.add(state, action, reward, next_state, done)
self.t_step += 1
if self.t_step % LOCAL_UPDATE == 0:
"""If there are enough experiences"""
if self.buffer.__len__() > BATCH_SIZE:
experiences = self.buffer.sample()
self.learn(experiences)
# self.target_update_t += 1
# if self.target_update_t % TARGET_UPDATE == 0:
self.soft_target_model_update(TAU)
def learn(self, experiences):
"""experiences ;tensor """
states, actions, rewards, next_states, dones = experiences
pred_q = self.local_model(states).gather(1, actions)
if self.double:
_, argmax_actions = torch.max(
self.local_model.forward(next_states).detach(),
1,
keepdim=True)
pred_next_q = self.target_model.forward(next_states).gather(
1, argmax_actions)
else:
pred_next_q, _ = torch.max(
self.target_model.forward(next_states).detach(),
1,
keepdim=True)
target_q = rewards + (
(1 - dones) * self.discounted_factor * pred_next_q)
loss = F.mse_loss(target_q, pred_q)
self.optimizer.zero_grad()
loss.backward()
self.optimizer.step()
def soft_target_model_update(self, tau):
for target_param, local_param in zip(self.target_model.parameters(),
self.local_model.parameters()):
target_param.data.copy_(tau * local_param.data +
(1.0 - tau) * target_param.data)
class Agent:
def __init__(self,
state_size,
action_size,
gamma=0.99,
lr=5e-4,
buffer_size=int(1e5),
batch_size=64,
tau=1e-3):
# defining local and target networks
self.qnet_local = Qnetwork(state_size, action_size).to(device)
self.qnet_target = Qnetwork(state_size, action_size).to(device)
# set local and target parameters equal to each other
self.soft_update(tau=1.0)
# experience replay buffer
self.memory = ReplayBuffer(buffer_size, batch_size)
# defining variables
self.state_size = state_size
self.action_size = action_size
self.buffer_size = buffer_size
self.batch_size = batch_size
self.gamma = gamma
self.lr = lr
self.tau = tau
self.t_step = 0
# optimizer
self.optimizer = optim.Adam(self.qnet_local.parameters(), lr=self.lr)
def step(self, state, action, reward, next_state, done):
""" saves the step info in the memory buffer and perform a learning iteration
Input :
state,action,reward,state,done : non-batched numpy arrays
Output :
none
"""
# add sample to the memory buffer
self.memory.add(state, action, reward, next_state, done)
# Learn every UPDATE_EVERY time steps.
self.t_step = (self.t_step + 1) % UPDATE_EVERY
# use replay buffer to learn if it has enough samples
if self.t_step == 0:
if len(self.memory) > self.batch_size:
experiences = self.memory.sample()
self.learn(experiences)
def learn(self, experiences):
""" perform a learning iteration by using sampled experience batch
Input :
experience : tuple from the memory buffer
states, actions, rewards, next_states, dones = experiences
eg : states.shape = [N,state_size]
Output :
none
"""
states, actions, rewards, next_states, dones, wj, choose = experiences
#states, actions, rewards, next_states, dones = experiences
# set optimizer grdient to zero
self.optimizer.zero_grad()
# predicted action value
q_pred = self.qnet_local.forward(states).gather(1, actions)
# target action value
## use double DQNs, refer https://arxiv.org/abs/1509.06461
next_action_local = self.qnet_local.forward(next_states).max(1)[1]
q_target = rewards + self.gamma * (
1 - dones) * self.qnet_target.forward(next_states)[
range(self.batch_size), next_action_local].unsqueeze(1)
# compute td error
td_error = q_target - q_pred
# update td error in Replay buffer
self.memory.update_td_error(choose,
td_error.detach().cpu().numpy().squeeze())
# defining loss
loss = ((wj * td_error)**2).mean()
# running backprop and optimizer step
loss.backward()
self.optimizer.step()
# run soft update
self.soft_update(self.tau)
def act(self, state, eps=0.):
""" return the local model's predicted action for the given state
Input :
state : [state_size]
Output :
action : scalar action as action space is discrete with dim = 1
"""
state = torch.from_numpy(state).float().unsqueeze(dim=0).to(
device) # converts numpy array to torch tensor
self.qnet_local.eval() # put net in test mode
with torch.no_grad():
max_action = np.argmax(
self.qnet_local(state)[0].cpu().data.numpy())
self.qnet_local.train() # put net back in train mode
rand_num = np.random.rand(
) # sample a random number uniformly between 0 and 1
# implementing epsilon greedy policy
if rand_num < eps:
return np.random.randint(self.action_size)
else:
return max_action
def soft_update(self, tau):
"""Soft update model parameters.
θ_target = τ*θ_local + (1 - τ)*θ_target
"""
for target_param, local_param in zip(self.qnet_target.parameters(),
self.qnet_local.parameters()):
target_param.data.copy_(tau * local_param.data +
(1.0 - tau) * target_param.data)
op_holder = []
for idx, var in enumerate(tfVars[0:total_vars // 2]):
op_holder.append(
tfVars[idx + total_vars // 2].assign((var.value() * tau) + (
(1 - tau) * tfVars[idx + total_vars // 2].value())))
return op_holder
def updateTarget(op_holder, sess):
for op in op_holder:
sess.run(op)
# training
tf.reset_default_graph()
mainQN = Qnetwork(h_size, env)
targetQN = Qnetwork(h_size, env)
init = tf.global_variables_initializer()
saver = tf.train.Saver()
trainables = tf.trainable_variables()
targetOps = updateTargetGraph(trainables, tau)
myBuffer = experience_buffer()
# Set the rate of random action decrease.
e = startE
stepDrop = (startE - endE) / anneling_steps
class Agent():
'''
Agent interacts with env and learn the optimal policy by learning optimal value function
'''
def __init__(self, state_size, action_size):
self.state_size = state_size
self.action_size = action_size
self.Qlocal = Qnetwork(self.state_size,
self.action_size).to(device) # Local Network
self.Qtarget = Qnetwork(self.state_size,
self.action_size).to(device) # Taget Network
self.optim = optim.Adam(self.Qlocal.parameters(), lr)
self.buffer = replay_buffer(buffer_max_size,
batch_size) # replay buffer
self.t_step = 0 # used in updating the target network weights from local network
def learn(self, exp, gamma):
'''
takes exp and gamma for training the local network in predicting proper q value
calculates the next time step q value from next state
'''
state, action, reward, next_state, done = exp
index = self.Qlocal(next_state).detach().max(1)[1].unsqueeze(
1
) # double q learning to get max value of action from secondary network
q_val = self.Qtarget(next_state).detach().gather(
1, index) # get the q value from the index which gave max value
y_onehot = torch.zeros(
batch_size,
self.action_size).cuda() # update the values for choosen action
y_onehot.scatter_(1, action, 1) # creating the one hot vector
Q_val_n = reward + (gamma * q_val * (1 - done)
) # Estimated the Target Q value for state
Q_target = y_onehot * Q_val_n # Traget network Qvalue for given action
pre = self.Qlocal(state) # Qvalue estimated by the local network
Q_local = y_onehot * pre # Local network Qvalue for given action
loss = F.mse_loss(Q_local, Q_target) # Loss function
self.optim.zero_grad()
loss.backward()
self.optim.step()
self.update(
self.Qlocal, self.Qtarget, tau
) # updating the Target network weight with Local network weight
def step(self, state, action, reward, next_state, done):
'''
Interacts with the env to get the one step experience and update the replay buffer
trains Local network one in four times it interacts with env
'''
self.buffer.add(state, action, reward, next_state,
done) # Adding to replay buffer
self.t_step += 1
if (self.t_step % 4 == 0): # Training ones in four times
if (len(self.buffer) > batch_size):
experiences = self.buffer.sample()
self.learn(experiences, gamma)
def act(self, state, eps):
'''
Given the state provide the appropriate action given by e-greedy policy
'''
state = torch.from_numpy(state).float().unsqueeze(0).to(device)
self.Qlocal.eval() # network in eval mode to calculate the q value
with torch.no_grad():
action_values = self.Qlocal(
state) # Q value estimate for given state
self.Qlocal.train() # network in train mode
if random.random(
) > eps: # e-greedy policy for choosing the action from q values
return np.argmax(action_values.cpu().data.numpy())
else:
return random.choice(np.arange(self.action_size))
def update(self, local_model, target_model, tau):
'''
Updates the Target network with some part of local network
'''
for l, t in zip(local_model.parameters(), target_model.parameters()):
t.data.copy_(t.data * (1.0 - tau) + l.data * tau)
class Agent():
"""Interacts with and learns from the environment."""
def __init__(self, state_size, action_size):
"""Initialize an Agent object.
Params
======
state_size (int): dimension of each state
action_size (int): dimension of each action
"""
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).to(device)
self.qnetwork_target = Qnetwork(state_size, action_size).to(device)
self.optimizer = optim.Adam(self.qnetwork_local.parameters(), lr=LR)
# Replay memory
self.memory = ReplayBuffer(action_size, BUFFER_SIZE, BATCH_SIZE)
# 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) > 1000:
experiences = self.memory.sample()
self.learn(experiences, GAMMA)
def act(self, state, eps=0.):
"""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)
self.qnetwork_local.train()
# Epsilon-greedy action selection
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 value parameters using given batch of experience tuples.
Params
======
experiences (Tuple[torch.Tensor]): tuple of (s, a, r, s', done) tuples
gamma (float): discount factor
"""
states, actions, rewards, next_states, dones = experiences
## TODO: compute and minimize the loss
"*** YOUR CODE HERE ***"
nxt_pred = 0.04 * torch.log(
torch.exp(self.qnetwork_target(next_states) *
25.0).sum(-1)).detach().unsqueeze(1)
y_onehot = torch.zeros(BATCH_SIZE, self.action_size).to(device)
y_onehot.scatter_(1, actions, 1)
Q_val_n = rewards + (gamma * nxt_pred * (1 - dones))
Q_target = y_onehot * Q_val_n
pre = self.qnetwork_local(states)
Q_local = y_onehot * pre
loss = F.mse_loss(Q_local, Q_target)
self.optimizer.zero_grad()
loss.backward()
torch.nn.utils.clip_grad_norm_(self.qnetwork_local.parameters(), 1)
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)