class DDPG(object):
def __init__(self,
actor,
critic,
memory,
observation_shape,
action_shape,
param_noise=None,
action_noise=None,
gamma=0.99,
tau=0.001,
normalize_returns=False,
enable_popart=False,
normalize_observations=True,
batch_size=128,
observation_range=(-5., 5.),
action_range=(-1., 1.),
return_range=(-np.inf, np.inf),
critic_l2_reg=0.,
actor_lr=1e-4,
critic_lr=1e-3,
clip_norm=None,
reward_scale=1.):
# Inputs.
self.obs0 = tf.placeholder(tf.float32,
shape=(None, ) + observation_shape,
name='obs0')
self.obs1 = tf.placeholder(tf.float32,
shape=(None, ) + observation_shape,
name='obs1')
self.terminals1 = tf.placeholder(tf.float32,
shape=(None, 1),
name='terminals1')
self.rewards = tf.placeholder(tf.float32,
shape=(None, 1),
name='rewards')
self.actions = tf.placeholder(tf.float32,
shape=(None, ) + action_shape,
name='actions')
self.critic_target = tf.placeholder(tf.float32,
shape=(None, 1),
name='critic_target')
self.param_noise_stddev = tf.placeholder(tf.float32,
shape=(),
name='param_noise_stddev')
# Parameters.
self.gamma = gamma
self.tau = tau
self.memory = memory
self.normalize_observations = normalize_observations
self.normalize_returns = normalize_returns
self.action_noise = action_noise
self.param_noise = param_noise
self.action_range = action_range
self.return_range = return_range
self.observation_range = observation_range
self.critic = critic
self.actor = actor
self.actor_lr = actor_lr
self.critic_lr = critic_lr
self.clip_norm = clip_norm
self.enable_popart = enable_popart
self.reward_scale = reward_scale
self.batch_size = batch_size
self.stats_sample = None
self.critic_l2_reg = critic_l2_reg
# Observation normalization.
if self.normalize_observations:
with tf.variable_scope('obs_rms'):
self.obs_rms = RunningMeanStd(shape=observation_shape)
else:
self.obs_rms = None
normalized_obs0 = tf.clip_by_value(normalize(self.obs0, self.obs_rms),
self.observation_range[0],
self.observation_range[1])
normalized_obs1 = tf.clip_by_value(normalize(self.obs1, self.obs_rms),
self.observation_range[0],
self.observation_range[1])
# Return normalization.
if self.normalize_returns:
with tf.variable_scope('ret_rms'):
self.ret_rms = RunningMeanStd()
else:
self.ret_rms = None
# Create target networks.
target_actor = copy(actor)
target_actor.name = 'target_actor'
self.target_actor = target_actor
target_critic = copy(critic)
target_critic.name = 'target_critic'
self.target_critic = target_critic
# Create networks and core TF parts that are shared across setup parts.
self.actor_tf = actor(normalized_obs0)
self.normalized_critic_tf, self.normalized_critic_ve, self.normalized_critic_fs = critic(
normalized_obs0, self.actions)
self.critic_tf = denormalize(
tf.clip_by_value(self.normalized_critic_tf, self.return_range[0],
self.return_range[1]), self.ret_rms)
self.normalized_critic_with_actor_tf, _, _ = critic(normalized_obs0,
self.actor_tf,
reuse=True)
self.critic_with_actor_tf = denormalize(
tf.clip_by_value(self.normalized_critic_with_actor_tf,
self.return_range[0], self.return_range[1]),
self.ret_rms)
Q_obs1, _, _ = denormalize(
target_critic(normalized_obs1, target_actor(normalized_obs1)),
self.ret_rms)
self.target_Q = self.rewards + (1. - self.terminals1) * gamma * Q_obs1
# Set up parts.
if self.param_noise is not None:
self.setup_param_noise(normalized_obs0)
self.setup_actor_optimizer()
self.setup_critic_optimizer()
if self.normalize_returns and self.enable_popart:
self.setup_popart()
self.setup_stats()
self.setup_target_network_updates()
self.initial_state = None # recurrent architectures not supported yet
def setup_target_network_updates(self):
actor_init_updates, actor_soft_updates = get_target_updates(
self.actor.vars, self.target_actor.vars, self.tau)
critic_init_updates, critic_soft_updates = get_target_updates(
self.critic.vars, self.target_critic.vars, self.tau)
self.target_init_updates = [actor_init_updates, critic_init_updates]
self.target_soft_updates = [actor_soft_updates, critic_soft_updates]
def setup_param_noise(self, normalized_obs0):
assert self.param_noise is not None
# Configure perturbed actor.
param_noise_actor = copy(self.actor)
param_noise_actor.name = 'param_noise_actor'
self.perturbed_actor_tf = param_noise_actor(normalized_obs0)
logger.info('setting up param noise')
self.perturb_policy_ops = get_perturbed_actor_updates(
self.actor, param_noise_actor, self.param_noise_stddev)
# Configure separate copy for stddev adoption.
adaptive_param_noise_actor = copy(self.actor)
adaptive_param_noise_actor.name = 'adaptive_param_noise_actor'
adaptive_actor_tf = adaptive_param_noise_actor(normalized_obs0)
self.perturb_adaptive_policy_ops = get_perturbed_actor_updates(
self.actor, adaptive_param_noise_actor, self.param_noise_stddev)
self.adaptive_policy_distance = tf.sqrt(
tf.reduce_mean(tf.square(self.actor_tf - adaptive_actor_tf)))
def setup_actor_optimizer(self):
logger.info('setting up actor optimizer')
self.actor_loss = -tf.reduce_mean(self.critic_with_actor_tf)
actor_shapes = [
var.get_shape().as_list() for var in self.actor.trainable_vars
]
actor_nb_params = sum(
[reduce(lambda x, y: x * y, shape) for shape in actor_shapes])
logger.info(' actor shapes: {}'.format(actor_shapes))
logger.info(' actor params: {}'.format(actor_nb_params))
self.actor_grads = U.flatgrad(self.actor_loss,
self.actor.trainable_vars,
clip_norm=self.clip_norm)
self.actor_optimizer = MpiAdam(var_list=self.actor.trainable_vars,
beta1=0.9,
beta2=0.999,
epsilon=1e-08)
def setup_critic_optimizer(self):
logger.info('setting up critic optimizer')
normalized_critic_target_tf = tf.clip_by_value(
normalize(self.critic_target, self.ret_rms), self.return_range[0],
self.return_range[1])
# Variance explained (Vexp)
_, var_r = tf.nn.moments(normalized_critic_target_tf, axes=0)
_, var_rv = tf.nn.moments(normalized_critic_target_tf -
self.normalized_critic_tf,
axes=0)
ve = 1 - var_rv / var_r
# Final Vexp loss
self.ve_loss = tf.reduce_mean(tf.square(ve -
self.normalized_critic_ve))
# NSA loss
self.fs_loss = tf.losses.cosine_distance(
tf.nn.l2_normalize(self.obs0[1:], 1),
tf.nn.l2_normalize(self.normalized_critic_fs[:-1], 1),
axis=1,
reduction=Reduction.MEAN)
self.vf_loss = tf.reduce_mean(
tf.square(self.normalized_critic_tf - normalized_critic_target_tf))
self.critic_loss = self.vf_loss + 0.5 * self.ve_loss + 0.01 * self.fs_loss
if self.critic_l2_reg > 0.:
critic_reg_vars = [
var for var in self.critic.trainable_vars
if var.name.endswith('/w:0') and 'output' not in var.name
]
for var in critic_reg_vars:
logger.info(' regularizing: {}'.format(var.name))
logger.info(' applying l2 regularization with {}'.format(
self.critic_l2_reg))
critic_reg = tc.layers.apply_regularization(
tc.layers.l2_regularizer(self.critic_l2_reg),
weights_list=critic_reg_vars)
self.critic_loss += critic_reg
critic_shapes = [
var.get_shape().as_list() for var in self.critic.trainable_vars
]
critic_nb_params = sum(
[reduce(lambda x, y: x * y, shape) for shape in critic_shapes])
logger.info(' critic shapes: {}'.format(critic_shapes))
logger.info(' critic params: {}'.format(critic_nb_params))
self.critic_grads = U.flatgrad(self.critic_loss,
self.critic.trainable_vars,
clip_norm=self.clip_norm)
self.critic_optimizer = MpiAdam(var_list=self.critic.trainable_vars,
beta1=0.9,
beta2=0.999,
epsilon=1e-08)
def setup_popart(self):
# See https://arxiv.org/pdf/1602.07714.pdf for details.
self.old_std = tf.placeholder(tf.float32, shape=[1], name='old_std')
new_std = self.ret_rms.std
self.old_mean = tf.placeholder(tf.float32, shape=[1], name='old_mean')
new_mean = self.ret_rms.mean
self.renormalize_Q_outputs_op = []
for vs in [self.critic.output_vars, self.target_critic.output_vars]:
assert len(vs) == 2
M, b = vs
assert 'kernel' in M.name
assert 'bias' in b.name
assert M.get_shape()[-1] == 1
assert b.get_shape()[-1] == 1
self.renormalize_Q_outputs_op += [
M.assign(M * self.old_std / new_std)
]
self.renormalize_Q_outputs_op += [
b.assign(
(b * self.old_std + self.old_mean - new_mean) / new_std)
]
def setup_stats(self):
ops = []
names = []
if self.normalize_returns:
ops += [self.ret_rms.mean, self.ret_rms.std]
names += ['ret_rms_mean', 'ret_rms_std']
if self.normalize_observations:
ops += [
tf.reduce_mean(self.obs_rms.mean),
tf.reduce_mean(self.obs_rms.std)
]
names += ['obs_rms_mean', 'obs_rms_std']
ops += [tf.reduce_mean(self.critic_tf)]
names += ['reference_Q_mean']
ops += [reduce_std(self.critic_tf)]
names += ['reference_Q_std']
ops += [tf.reduce_mean(self.critic_with_actor_tf)]
names += ['reference_actor_Q_mean']
ops += [reduce_std(self.critic_with_actor_tf)]
names += ['reference_actor_Q_std']
ops += [tf.reduce_mean(self.actor_tf)]
names += ['reference_action_mean']
ops += [reduce_std(self.actor_tf)]
names += ['reference_action_std']
if self.param_noise:
ops += [tf.reduce_mean(self.perturbed_actor_tf)]
names += ['reference_perturbed_action_mean']
ops += [reduce_std(self.perturbed_actor_tf)]
names += ['reference_perturbed_action_std']
self.stats_ops = ops
self.stats_names = names
def step(self, obs, apply_noise=True, compute_Q=True):
if self.param_noise is not None and apply_noise:
actor_tf = self.perturbed_actor_tf
else:
actor_tf = self.actor_tf
feed_dict = {self.obs0: U.adjust_shape(self.obs0, [obs])}
if compute_Q:
action, q = self.sess.run([actor_tf, self.critic_with_actor_tf],
feed_dict=feed_dict)
else:
action = self.sess.run(actor_tf, feed_dict=feed_dict)
q = None
if self.action_noise is not None and apply_noise:
noise = self.action_noise()
assert noise.shape == action[0].shape
action += noise
action = np.clip(action, self.action_range[0], self.action_range[1])
return action, q, None, None
def store_transition(self, obs0, action, reward, obs1, terminal1):
reward *= self.reward_scale
B = obs0.shape[0]
for b in range(B):
self.memory.append(obs0[b], action[b], reward[b], obs1[b],
terminal1[b])
if self.normalize_observations:
self.obs_rms.update(np.array([obs0[b]]))
def train(self):
# Get a batch.
batch = self.memory.sample(batch_size=self.batch_size)
if self.normalize_returns and self.enable_popart:
old_mean, old_std, target_Q = self.sess.run(
[self.ret_rms.mean, self.ret_rms.std, self.target_Q],
feed_dict={
self.obs1: batch['obs1'],
self.rewards: batch['rewards'],
self.terminals1: batch['terminals1'].astype('float32'),
})
self.ret_rms.update(target_Q.flatten())
self.sess.run(self.renormalize_Q_outputs_op,
feed_dict={
self.old_std: np.array([old_std]),
self.old_mean: np.array([old_mean]),
})
# Run sanity check. Disabled by default since it slows down things considerably.
# print('running sanity check')
# target_Q_new, new_mean, new_std = self.sess.run([self.target_Q, self.ret_rms.mean, self.ret_rms.std], feed_dict={
# self.obs1: batch['obs1'],
# self.rewards: batch['rewards'],
# self.terminals1: batch['terminals1'].astype('float32'),
# })
# print(target_Q_new, target_Q, new_mean, new_std)
# assert (np.abs(target_Q - target_Q_new) < 1e-3).all()
else:
target_Q = self.sess.run(self.target_Q,
feed_dict={
self.obs1:
batch['obs1'],
self.rewards:
batch['rewards'],
self.terminals1:
batch['terminals1'].astype('float32'),
})
# Get all gradients and perform a synced update.
ops = [
self.actor_grads, self.actor_loss, self.critic_grads,
self.critic_loss
]
actor_grads, actor_loss, critic_grads, critic_loss = self.sess.run(
ops,
feed_dict={
self.obs0: batch['obs0'],
self.actions: batch['actions'],
self.critic_target: target_Q,
})
self.actor_optimizer.update(actor_grads, stepsize=self.actor_lr)
self.critic_optimizer.update(critic_grads, stepsize=self.critic_lr)
return critic_loss, actor_loss
def initialize(self, sess):
self.sess = sess
self.sess.run(tf.global_variables_initializer())
self.actor_optimizer.sync()
self.critic_optimizer.sync()
self.sess.run(self.target_init_updates)
def update_target_net(self):
self.sess.run(self.target_soft_updates)
def get_stats(self):
if self.stats_sample is None:
# Get a sample and keep that fixed for all further computations.
# This allows us to estimate the change in value for the same set of inputs.
self.stats_sample = self.memory.sample(batch_size=self.batch_size)
values = self.sess.run(self.stats_ops,
feed_dict={
self.obs0: self.stats_sample['obs0'],
self.actions: self.stats_sample['actions'],
})
names = self.stats_names[:]
assert len(names) == len(values)
stats = dict(zip(names, values))
if self.param_noise is not None:
stats = {**stats, **self.param_noise.get_stats()}
return stats
def adapt_param_noise(self):
try:
from mpi4py import MPI
except ImportError:
MPI = None
if self.param_noise is None:
return 0.
# Perturb a separate copy of the policy to adjust the scale for the next "real" perturbation.
batch = self.memory.sample(batch_size=self.batch_size)
self.sess.run(self.perturb_adaptive_policy_ops,
feed_dict={
self.param_noise_stddev:
self.param_noise.current_stddev,
})
distance = self.sess.run(self.adaptive_policy_distance,
feed_dict={
self.obs0:
batch['obs0'],
self.param_noise_stddev:
self.param_noise.current_stddev,
})
if MPI is not None:
mean_distance = MPI.COMM_WORLD.allreduce(
distance, op=MPI.SUM) / MPI.COMM_WORLD.Get_size()
else:
mean_distance = distance
if MPI is not None:
mean_distance = MPI.COMM_WORLD.allreduce(
distance, op=MPI.SUM) / MPI.COMM_WORLD.Get_size()
else:
mean_distance = distance
self.param_noise.adapt(mean_distance)
return mean_distance
def reset(self):
# Reset internal state after an episode is complete.
if self.action_noise is not None:
self.action_noise.reset()
if self.param_noise is not None:
self.sess.run(self.perturb_policy_ops,
feed_dict={
self.param_noise_stddev:
self.param_noise.current_stddev,
})
def __init__(self,
actor,
critic,
memory,
observation_shape,
action_shape,
param_noise=None,
action_noise=None,
gamma=0.99,
tau=0.001,
normalize_returns=False,
enable_popart=False,
normalize_observations=True,
batch_size=128,
observation_range=(-5., 5.),
action_range=(-1., 1.),
return_range=(-np.inf, np.inf),
critic_l2_reg=0.,
actor_lr=1e-4,
critic_lr=1e-3,
clip_norm=None,
reward_scale=1.):
# Inputs.
self.obs0 = tf.placeholder(tf.float32,
shape=(None, ) + observation_shape,
name='obs0')
self.obs1 = tf.placeholder(tf.float32,
shape=(None, ) + observation_shape,
name='obs1')
self.terminals1 = tf.placeholder(tf.float32,
shape=(None, 1),
name='terminals1')
self.rewards = tf.placeholder(tf.float32,
shape=(None, 1),
name='rewards')
self.actions = tf.placeholder(tf.float32,
shape=(None, ) + action_shape,
name='actions')
self.critic_target = tf.placeholder(tf.float32,
shape=(None, 1),
name='critic_target')
self.param_noise_stddev = tf.placeholder(tf.float32,
shape=(),
name='param_noise_stddev')
# Parameters.
self.gamma = gamma
self.tau = tau
self.memory = memory
self.normalize_observations = normalize_observations
self.normalize_returns = normalize_returns
self.action_noise = action_noise
self.param_noise = param_noise
self.action_range = action_range
self.return_range = return_range
self.observation_range = observation_range
self.critic = critic
self.actor = actor
self.actor_lr = actor_lr
self.critic_lr = critic_lr
self.clip_norm = clip_norm
self.enable_popart = enable_popart
self.reward_scale = reward_scale
self.batch_size = batch_size
self.stats_sample = None
self.critic_l2_reg = critic_l2_reg
# Observation normalization.
if self.normalize_observations:
with tf.variable_scope('obs_rms'):
self.obs_rms = RunningMeanStd(shape=observation_shape)
else:
self.obs_rms = None
normalized_obs0 = tf.clip_by_value(normalize(self.obs0, self.obs_rms),
self.observation_range[0],
self.observation_range[1])
normalized_obs1 = tf.clip_by_value(normalize(self.obs1, self.obs_rms),
self.observation_range[0],
self.observation_range[1])
# Return normalization.
if self.normalize_returns:
with tf.variable_scope('ret_rms'):
self.ret_rms = RunningMeanStd()
else:
self.ret_rms = None
# Create target networks.
target_actor = copy(actor)
target_actor.name = 'target_actor'
self.target_actor = target_actor
target_critic = copy(critic)
target_critic.name = 'target_critic'
self.target_critic = target_critic
# Create networks and core TF parts that are shared across setup parts.
self.actor_tf = actor(normalized_obs0)
self.normalized_critic_tf, self.normalized_critic_ve, self.normalized_critic_fs = critic(
normalized_obs0, self.actions)
self.critic_tf = denormalize(
tf.clip_by_value(self.normalized_critic_tf, self.return_range[0],
self.return_range[1]), self.ret_rms)
self.normalized_critic_with_actor_tf, _, _ = critic(normalized_obs0,
self.actor_tf,
reuse=True)
self.critic_with_actor_tf = denormalize(
tf.clip_by_value(self.normalized_critic_with_actor_tf,
self.return_range[0], self.return_range[1]),
self.ret_rms)
Q_obs1, _, _ = denormalize(
target_critic(normalized_obs1, target_actor(normalized_obs1)),
self.ret_rms)
self.target_Q = self.rewards + (1. - self.terminals1) * gamma * Q_obs1
# Set up parts.
if self.param_noise is not None:
self.setup_param_noise(normalized_obs0)
self.setup_actor_optimizer()
self.setup_critic_optimizer()
if self.normalize_returns and self.enable_popart:
self.setup_popart()
self.setup_stats()
self.setup_target_network_updates()
self.initial_state = None # recurrent architectures not supported yet
def _normalize_clip_observation(x, clip_range=[-5.0, 5.0]):
rms = RunningMeanStd(shape=x.shape[1:])
norm_x = tf.clip_by_value((x - rms.mean) / rms.std, min(clip_range),
max(clip_range))
return norm_x, rms