class GaussActor(nn.Module):
""" Actor which learns mean and standard deviation of Gaussian
stochastic policy. Actions obtained from the policy are squashed
with (out_activation).
"""
def __init__(self,
state_shape,
action_size,
hiddens,
layer_fn,
activation_fn=nn.ReLU,
norm_fn=None,
bias=True,
out_activation=nn.Sigmoid):
super().__init__()
# hack to prevent cycle imports
from catalyst.modules.modules import name2nn
self.n_action = action_size
layer_fn = name2nn(layer_fn)
activation_fn = name2nn(activation_fn)
norm_fn = name2nn(norm_fn)
out_activation = name2nn(out_activation)
state_size = reduce(lambda x, y: x * y, state_shape)
self.feature_net = SequentialNet(hiddens=[state_size] + hiddens,
layer_fn=layer_fn,
activation_fn=activation_fn,
norm_fn=norm_fn,
bias=bias)
self.policy_net = SequentialNet(hiddens=[hiddens[-1], action_size * 2],
layer_fn=nn.Linear,
activation_fn=None,
norm_fn=None,
bias=bias)
self.squasher = SquashingLayer(out_activation)
inner_init = create_optimal_inner_init(nonlinearity=activation_fn)
self.feature_net.apply(inner_init)
self.policy_net.apply(outer_init)
def forward(self, observation, with_log_pi=False):
observation = observation.view(observation.shape[0], -1)
x = observation
x = self.feature_net.forward(x)
x = self.policy_net.forward(x)
mu, log_sigma = x[:, :self.n_action], x[:, self.n_action:]
log_sigma = torch.clamp(log_sigma, LOG_SIG_MIN, LOG_SIG_MAX)
sigma = torch.exp(log_sigma)
z = normal_sample(mu, sigma)
log_pi = normal_log_prob(mu, sigma, z)
action, log_pi = self.squasher.forward(z, log_pi)
if with_log_pi:
return action, log_pi, mu, log_sigma
return action
class ValueCritic(nn.Module):
""" Critic which learns value function V(s).
"""
def __init__(self,
state_shape,
hiddens,
layer_fn,
n_atoms=1,
activation_fn=nn.ReLU,
norm_fn=None,
bias=True,
out_activation=None):
super().__init__()
# hack to prevent cycle imports
from catalyst.modules.modules import name2nn
layer_fn = name2nn(layer_fn)
activation_fn = name2nn(activation_fn)
norm_fn = name2nn(norm_fn)
out_activation = name2nn(out_activation)
self.n_atoms = n_atoms
state_size = reduce(lambda x, y: x * y, state_shape)
hiddens_ = [state_size] + hiddens
self.feature_net = SequentialNet(hiddens=hiddens_,
layer_fn=layer_fn,
activation_fn=activation_fn,
norm_fn=norm_fn,
bias=bias)
self.value_net = SequentialNet(hiddens=[hiddens[-1], n_atoms],
layer_fn=nn.Linear,
activation_fn=out_activation,
norm_fn=None,
bias=True)
inner_init = create_optimal_inner_init(nonlinearity=activation_fn)
self.feature_net.apply(inner_init)
self.value_net.apply(outer_init)
def forward(self, observation):
x = observation.view(observation.shape[0], -1)
x = self.feature_net.forward(x)
x = self.value_net.forward(x)
return x
class Actor(nn.Module):
""" Actor which learns deterministic policy.
"""
def __init__(self,
state_shape,
action_size,
hiddens,
layer_fn,
activation_fn=nn.ReLU,
norm_fn=None,
bias=True,
out_activation=nn.Tanh):
super().__init__()
# hack to prevent cycle imports
from catalyst.modules.modules import name2nn
layer_fn = name2nn(layer_fn)
activation_fn = name2nn(activation_fn)
norm_fn = name2nn(norm_fn)
out_activation = name2nn(out_activation)
state_size = reduce(lambda x, y: x * y, state_shape)
self.feature_net = SequentialNet(hiddens=[state_size] + hiddens,
layer_fn=layer_fn,
activation_fn=activation_fn,
norm_fn=norm_fn,
bias=bias)
self.policy_net = SequentialNet(hiddens=[hiddens[-1], action_size],
layer_fn=nn.Linear,
activation_fn=out_activation,
norm_fn=None,
bias=True)
inner_init = create_optimal_inner_init(nonlinearity=activation_fn)
self.feature_net.apply(inner_init)
self.policy_net.apply(outer_init)
def forward(self, states):
x = states.view(states.shape[0], -1)
x = self.feature_net.forward(x)
x = self.policy_net.forward(x)
return x
class Critic(nn.Module):
""" Critic which learns state-action value function Q(s,a).
"""
def __init__(self,
state_shape,
action_size,
hiddens,
layer_fn,
concat_at=1,
n_atoms=1,
activation_fn=nn.ReLU,
norm_fn=None,
bias=True,
out_activation=None):
super().__init__()
# hack to prevent cycle imports
from catalyst.modules.modules import name2nn
layer_fn = name2nn(layer_fn)
activation_fn = name2nn(activation_fn)
norm_fn = name2nn(norm_fn)
out_activation = name2nn(out_activation)
self.n_atoms = n_atoms
state_size = reduce(lambda x, y: x * y, state_shape)
if concat_at > 0:
hiddens_ = [state_size] + hiddens[0:concat_at]
self.observation_net = SequentialNet(hiddens=hiddens_,
layer_fn=layer_fn,
activation_fn=activation_fn,
norm_fn=norm_fn,
bias=bias)
hiddens_ = \
[hiddens[concat_at - 1] + action_size] + hiddens[concat_at:]
self.feature_net = SequentialNet(hiddens=hiddens_,
layer_fn=layer_fn,
activation_fn=activation_fn,
norm_fn=norm_fn,
bias=bias)
else:
self.observation_net = None
hiddens_ = [state_size + action_size] + hiddens
self.feature_net = SequentialNet(hiddens=hiddens_,
layer_fn=layer_fn,
activation_fn=activation_fn,
norm_fn=norm_fn,
bias=bias)
self.value_net = SequentialNet(hiddens=[hiddens[-1], n_atoms],
layer_fn=nn.Linear,
activation_fn=out_activation,
norm_fn=None,
bias=True)
inner_init = create_optimal_inner_init(nonlinearity=activation_fn)
if self.observation_net is not None:
self.observation_net.apply(inner_init)
self.feature_net.apply(inner_init)
self.value_net.apply(outer_init)
def forward(self, observation, action):
observation = observation.view(observation.shape[0], -1)
if self.observation_net is not None:
observation = self.observation_net(observation)
x = torch.cat((observation, action), dim=1)
x = self.feature_net.forward(x)
x = self.value_net.forward(x)
return x
class RealNVPActor(nn.Module):
""" Actor which learns policy based on Real NVP Bijector.
Such policy transforms samples from N(z|0,I) into actions and
then squashes them with (out activation).
"""
def __init__(self,
state_shape,
action_size,
hiddens,
layer_fn,
activation_fn=nn.ReLU,
norm_fn=None,
bias=True,
out_activation=nn.Sigmoid):
super().__init__()
# hack to prevent cycle imports
from catalyst.modules.modules import name2nn
self.n_action = action_size
layer_fn = name2nn(layer_fn)
activation_fn = name2nn(activation_fn)
norm_fn = name2nn(norm_fn)
out_activation = name2nn(out_activation)
state_size = reduce(lambda x, y: x * y, state_shape)
self.feature_net = SequentialNet(hiddens=[state_size] + hiddens,
layer_fn=layer_fn,
activation_fn=activation_fn,
norm_fn=norm_fn,
bias=bias)
self.embedding_net = SequentialNet(
hiddens=[hiddens[-1], action_size * 2],
layer_fn=layer_fn,
activation_fn=None,
norm_fn=norm_fn,
bias=bias)
self.coupling1 = CouplingLayer(action_size=action_size,
layer_fn=layer_fn,
activation_fn=activation_fn,
norm_fn=None,
bias=bias,
parity="odd")
self.coupling2 = CouplingLayer(action_size=action_size,
layer_fn=layer_fn,
activation_fn=activation_fn,
norm_fn=None,
bias=bias,
parity="even")
self.squasher = SquashingLayer(out_activation)
inner_init = create_optimal_inner_init(nonlinearity=activation_fn)
self.feature_net.apply(inner_init)
self.embedding_net.apply(inner_init)
def forward(self, observation, with_log_pi=False):
observation = observation.view(observation.shape[0], -1)
x = observation
x = self.feature_net.forward(x)
state_embedding = self.embedding_net.forward(x)
mu = torch.zeros((observation.shape[0], self.n_action)).to(x.device)
sigma = torch.ones_like(mu).to(x.device)
z = normal_sample(mu, sigma)
log_pi = normal_log_prob(mu, sigma, z)
z, log_pi = self.coupling1.forward(z, state_embedding, log_pi)
z, log_pi = self.coupling2.forward(z, state_embedding, log_pi)
action, log_pi = self.squasher.forward(z, log_pi)
if with_log_pi:
return action, log_pi
return action