def td3(env_fn,
actor_critic=core.mlp_actor_critic,
ac_kwargs=dict(),
seed=0,
steps_per_epoch=4000,
epochs=100,
replay_size=int(1e6),
gamma=0.99,
polyak=0.995,
pi_lr=1e-3,
q_lr=1e-3,
batch_size=100,
start_steps=10000,
update_after=1000,
update_every=50,
act_noise=0.1,
target_noise=0.2,
noise_clip=0.5,
policy_delay=2,
num_test_episodes=10,
max_ep_len=1000,
logger_kwargs=dict(),
save_freq=1):
"""
Twin Delayed Deep Deterministic Policy Gradient (TD3)
Args:
env_fn : A function which creates a copy of the environment.
The environment must satisfy the OpenAI Gym API.
actor_critic: A function which takes in placeholder symbols
for state, ``x_ph``, and action, ``a_ph``, and returns the main
outputs from the agent's Tensorflow computation graph:
=========== ================ ======================================
Symbol Shape Description
=========== ================ ======================================
``pi`` (batch, act_dim) | Deterministically computes actions
| from policy given states.
``q1`` (batch,) | Gives one estimate of Q* for
| states in ``x_ph`` and actions in
| ``a_ph``.
``q2`` (batch,) | Gives another estimate of Q* for
| states in ``x_ph`` and actions in
| ``a_ph``.
``q1_pi`` (batch,) | Gives the composition of ``q1`` and
| ``pi`` for states in ``x_ph``:
| q1(x, pi(x)).
=========== ================ ======================================
ac_kwargs (dict): Any kwargs appropriate for the actor_critic
function you provided to TD3.
seed (int): Seed for random number generators.
steps_per_epoch (int): Number of steps of interaction (state-action pairs)
for the agent and the environment in each epoch.
epochs (int): Number of epochs to run and train agent.
replay_size (int): Maximum length of replay buffer.
gamma (float): Discount factor. (Always between 0 and 1.)
polyak (float): Interpolation factor in polyak averaging for target
networks. Target networks are updated towards main networks
according to:
.. math:: \\theta_{\\text{targ}} \\leftarrow
\\rho \\theta_{\\text{targ}} + (1-\\rho) \\theta
where :math:`\\rho` is polyak. (Always between 0 and 1, usually
close to 1.)
pi_lr (float): Learning rate for policy.
q_lr (float): Learning rate for Q-networks.
batch_size (int): Minibatch size for SGD.
start_steps (int): Number of steps for uniform-random action selection,
before running real policy. Helps exploration.
update_after (int): Number of env interactions to collect before
starting to do gradient descent updates. Ensures replay buffer
is full enough for useful updates.
update_every (int): Number of env interactions that should elapse
between gradient descent updates. Note: Regardless of how long
you wait between updates, the ratio of env steps to gradient steps
is locked to 1.
act_noise (float): Stddev for Gaussian exploration noise added to
policy at training time. (At test time, no noise is added.)
target_noise (float): Stddev for smoothing noise added to target
policy.
noise_clip (float): Limit for absolute value of target policy
smoothing noise.
policy_delay (int): Policy will only be updated once every
policy_delay times for each update of the Q-networks.
num_test_episodes (int): Number of episodes to test the deterministic
policy at the end of each epoch.
max_ep_len (int): Maximum length of trajectory / episode / rollout.
logger_kwargs (dict): Keyword args for EpochLogger.
save_freq (int): How often (in terms of gap between epochs) to save
the current policy and value function.
"""
logger = EpochLogger(**logger_kwargs)
logger.save_config(locals())
tf.set_random_seed(seed)
np.random.seed(seed)
env, test_env = env_fn(), env_fn()
obs_dim = env.observation_space.shape[0]
act_dim = env.action_space.shape[0]
# Action limit for clamping: critically, assumes all dimensions share the same bound!
act_limit = env.action_space.high[0]
# Share information about action space with policy architecture
ac_kwargs['action_space'] = env.action_space
# Inputs to computation graph
x_ph, a_ph, x2_ph, r_ph, d_ph = core.placeholders(obs_dim, act_dim,
obs_dim, None, None)
#=========================================================================#
# #
# All of your code goes in the space below. #
# #
#=========================================================================#
# Main outputs from computation graph
with tf.variable_scope('main'):
#######################
# #
# YOUR CODE HERE #
# #
#######################
# pi, q1, q2, q1_pi =
pass
# Target policy network
with tf.variable_scope('target'):
#######################
# #
# YOUR CODE HERE #
# #
#######################
# pi_targ =
pass
# Target Q networks
with tf.variable_scope('target', reuse=True):
# Target policy smoothing, by adding clipped noise to target actions
#######################
# #
# YOUR CODE HERE #
# #
#######################
# Target Q-values, using action from smoothed target policy
#######################
# #
# YOUR CODE HERE #
# #
#######################
pass
# Experience buffer
replay_buffer = ReplayBuffer(obs_dim=obs_dim,
act_dim=act_dim,
size=replay_size)
# Count variables
var_counts = tuple(
core.count_vars(scope)
for scope in ['main/pi', 'main/q1', 'main/q2', 'main'])
print(
'\nNumber of parameters: \t pi: %d, \t q1: %d, \t q2: %d, \t total: %d\n'
% var_counts)
# Bellman backup for Q functions, using Clipped Double-Q targets
#######################
# #
# YOUR CODE HERE #
# #
#######################
# TD3 losses
#######################
# #
# YOUR CODE HERE #
# #
#######################
# pi_loss =
# q1_loss =
# q2_loss =
# q_loss =
#=========================================================================#
# #
# All of your code goes in the space above. #
# #
#=========================================================================#
# Separate train ops for pi, q
pi_optimizer = tf.train.AdamOptimizer(learning_rate=pi_lr)
q_optimizer = tf.train.AdamOptimizer(learning_rate=q_lr)
train_pi_op = pi_optimizer.minimize(pi_loss, var_list=get_vars('main/pi'))
train_q_op = q_optimizer.minimize(q_loss, var_list=get_vars('main/q'))
# Polyak averaging for target variables
target_update = tf.group([
tf.assign(v_targ, polyak * v_targ + (1 - polyak) * v_main)
for v_main, v_targ in zip(get_vars('main'), get_vars('target'))
])
# Initializing targets to match main variables
target_init = tf.group([
tf.assign(v_targ, v_main)
for v_main, v_targ in zip(get_vars('main'), get_vars('target'))
])
sess = tf.Session()
sess.run(tf.global_variables_initializer())
sess.run(target_init)
# Setup model saving
logger.setup_tf_saver(sess,
inputs={
'x': x_ph,
'a': a_ph
},
outputs={
'pi': pi,
'q1': q1,
'q2': q2
})
def get_action(o, noise_scale):
a = sess.run(pi, feed_dict={x_ph: o.reshape(1, -1)})[0]
a += noise_scale * np.random.randn(act_dim)
return np.clip(a, -act_limit, act_limit)
def test_agent():
for j in range(num_test_episodes):
o, d, ep_ret, ep_len = test_env.reset(), False, 0, 0
while not (d or (ep_len == max_ep_len)):
# Take deterministic actions at test time (noise_scale=0)
o, r, d, _ = test_env.step(get_action(o, 0))
ep_ret += r
ep_len += 1
logger.store(TestEpRet=ep_ret, TestEpLen=ep_len)
start_time = time.time()
o, ep_ret, ep_len = env.reset(), 0, 0
total_steps = steps_per_epoch * epochs
# Main loop: collect experience in env and update/log each epoch
for t in range(total_steps):
# Until start_steps have elapsed, randomly sample actions
# from a uniform distribution for better exploration. Afterwards,
# use the learned policy (with some noise, via act_noise).
if t > start_steps:
a = get_action(o, act_noise)
else:
a = env.action_space.sample()
# Step the env
o2, r, d, _ = env.step(a)
ep_ret += r
ep_len += 1
# Ignore the "done" signal if it comes from hitting the time
# horizon (that is, when it's an artificial terminal signal
# that isn't based on the agent's state)
d = False if ep_len == max_ep_len else d
# Store experience to replay buffer
replay_buffer.store(o, a, r, o2, d)
# Super critical, easy to overlook step: make sure to update
# most recent observation!
o = o2
# End of trajectory handling
if d or (ep_len == max_ep_len):
logger.store(EpRet=ep_ret, EpLen=ep_len)
o, ep_ret, ep_len = env.reset(), 0, 0
# Update handling
if t >= update_after and t % update_every == 0:
for j in range(update_every):
batch = replay_buffer.sample_batch(batch_size)
feed_dict = {
x_ph: batch['obs1'],
x2_ph: batch['obs2'],
a_ph: batch['acts'],
r_ph: batch['rews'],
d_ph: batch['done']
}
q_step_ops = [q_loss, q1, q2, train_q_op]
outs = sess.run(q_step_ops, feed_dict)
logger.store(LossQ=outs[0], Q1Vals=outs[1], Q2Vals=outs[2])
if j % policy_delay == 0:
# Delayed policy update
outs = sess.run([pi_loss, train_pi_op, target_update],
feed_dict)
logger.store(LossPi=outs[0])
# End of epoch wrap-up
if (t + 1) % steps_per_epoch == 0:
epoch = (t + 1) // steps_per_epoch
# Save model
if (epoch % save_freq == 0) or (epoch == epochs):
logger.save_state({'env': env}, None)
# Test the performance of the deterministic version of the agent.
test_agent()
# Log info about epoch
logger.log_tabular('Epoch', epoch)
logger.log_tabular('EpRet', with_min_and_max=True)
logger.log_tabular('TestEpRet', with_min_and_max=True)
logger.log_tabular('EpLen', average_only=True)
logger.log_tabular('TestEpLen', average_only=True)
logger.log_tabular('TotalEnvInteracts', t)
logger.log_tabular('Q1Vals', with_min_and_max=True)
logger.log_tabular('Q2Vals', with_min_and_max=True)
logger.log_tabular('LossPi', average_only=True)
logger.log_tabular('LossQ', average_only=True)
logger.log_tabular('Time', time.time() - start_time)
logger.dump_tabular()
def train_mnist(steps_per_epoch=100,
epochs=5,
lr=1e-3,
layers=2,
hidden_size=64,
logger_kwargs=dict(),
save_freq=1):
logger = EpochLogger(**logger_kwargs)
logger.save_config(locals())
# Load and preprocess MNIST data
(x_train, y_train), _ = tf.keras.datasets.mnist.load_data()
x_train = x_train.reshape(-1, 28 * 28) / 255.0
# Define inputs & main outputs from computation graph
x_ph = tf.placeholder(tf.float32, shape=(None, 28 * 28))
y_ph = tf.placeholder(tf.int32, shape=(None, ))
logits = mlp(x_ph,
hidden_sizes=[hidden_size] * layers + [10],
activation=tf.nn.relu)
predict = tf.argmax(logits, axis=1, output_type=tf.int32)
# Define loss function, accuracy, and training op
y = tf.one_hot(y_ph, 10)
loss = tf.losses.softmax_cross_entropy(y, logits)
acc = tf.reduce_mean(tf.cast(tf.equal(y_ph, predict), tf.float32))
train_op = tf.train.AdamOptimizer().minimize(loss)
# Prepare session
sess = tf.Session()
sess.run(tf.global_variables_initializer())
# Setup model saving
logger.setup_tf_saver(sess,
inputs={'x': x_ph},
outputs={
'logits': logits,
'predict': predict
})
start_time = time.time()
# Run main training loop
for epoch in range(epochs):
for t in range(steps_per_epoch):
idxs = np.random.randint(0, len(x_train), 32)
feed_dict = {x_ph: x_train[idxs], y_ph: y_train[idxs]}
outs = sess.run([loss, acc, train_op], feed_dict=feed_dict)
logger.store(Loss=outs[0], Acc=outs[1])
# Save model
if (epoch % save_freq == 0) or (epoch == epochs - 1):
logger.save_state(state_dict=dict(), itr=None)
# Log info about epoch
logger.log_tabular('Epoch', epoch)
logger.log_tabular('Acc', with_min_and_max=True)
logger.log_tabular('Loss', average_only=True)
logger.log_tabular('TotalGradientSteps', (epoch + 1) * steps_per_epoch)
logger.log_tabular('Time', time.time() - start_time)
logger.dump_tabular()