import time
from contextlib import contextmanager
from collections import deque
import gym
from mpi4py import MPI
import tensorflow as tf
import numpy as np
import stable_baselines.common.tf_util as tf_util
from stable_baselines.common.tf_util import total_episode_reward_logger
from stable_baselines.common import explained_variance, zipsame, dataset, fmt_row, colorize, ActorCriticRLModel, \
SetVerbosity, TensorboardWriter
from stable_baselines import logger
from stable_baselines.common.mpi_adam import MpiAdam
from stable_baselines.common.cg import conjugate_gradient
from stable_baselines.common.policies import ActorCriticPolicy
from stable_baselines.common.misc_util import flatten_lists
from stable_baselines.common.runners import traj_segment_generator
from stable_baselines.trpo_mpi.utils import add_vtarg_and_adv
[docs]class TRPO(ActorCriticRLModel):
"""
Trust Region Policy Optimization (https://arxiv.org/abs/1502.05477)
:param policy: (ActorCriticPolicy or str) The policy model to use (MlpPolicy, CnnPolicy, CnnLstmPolicy, ...)
:param env: (Gym environment or str) The environment to learn from (if registered in Gym, can be str)
:param gamma: (float) the discount value
:param timesteps_per_batch: (int) the number of timesteps to run per batch (horizon)
:param max_kl: (float) the Kullback-Leibler loss threshold
:param cg_iters: (int) the number of iterations for the conjugate gradient calculation
:param lam: (float) GAE factor
:param entcoeff: (float) the weight for the entropy loss
:param cg_damping: (float) the compute gradient dampening factor
:param vf_stepsize: (float) the value function stepsize
:param vf_iters: (int) the value function's number iterations for learning
:param verbose: (int) the verbosity level: 0 none, 1 training information, 2 tensorflow debug
:param tensorboard_log: (str) the log location for tensorboard (if None, no logging)
:param _init_setup_model: (bool) Whether or not to build the network at the creation of the instance
:param policy_kwargs: (dict) additional arguments to be passed to the policy on creation
:param full_tensorboard_log: (bool) enable additional logging when using tensorboard
WARNING: this logging can take a lot of space quickly
:param seed: (int) Seed for the pseudo-random generators (python, numpy, tensorflow).
If None (default), use random seed. Note that if you want completely deterministic
results, you must set `n_cpu_tf_sess` to 1.
:param n_cpu_tf_sess: (int) The number of threads for TensorFlow operations
If None, the number of cpu of the current machine will be used.
"""
def __init__(self, policy, env, gamma=0.99, timesteps_per_batch=1024, max_kl=0.01, cg_iters=10, lam=0.98,
entcoeff=0.0, cg_damping=1e-2, vf_stepsize=3e-4, vf_iters=3, verbose=0, tensorboard_log=None,
_init_setup_model=True, policy_kwargs=None, full_tensorboard_log=False,
seed=None, n_cpu_tf_sess=1):
super(TRPO, self).__init__(policy=policy, env=env, verbose=verbose, requires_vec_env=False,
_init_setup_model=_init_setup_model, policy_kwargs=policy_kwargs,
seed=seed, n_cpu_tf_sess=n_cpu_tf_sess)
self.using_gail = False
self.timesteps_per_batch = timesteps_per_batch
self.cg_iters = cg_iters
self.cg_damping = cg_damping
self.gamma = gamma
self.lam = lam
self.max_kl = max_kl
self.vf_iters = vf_iters
self.vf_stepsize = vf_stepsize
self.entcoeff = entcoeff
self.tensorboard_log = tensorboard_log
self.full_tensorboard_log = full_tensorboard_log
# GAIL Params
self.hidden_size_adversary = 100
self.adversary_entcoeff = 1e-3
self.expert_dataset = None
self.g_step = 1
self.d_step = 1
self.d_stepsize = 3e-4
self.graph = None
self.sess = None
self.policy_pi = None
self.loss_names = None
self.assign_old_eq_new = None
self.compute_losses = None
self.compute_lossandgrad = None
self.compute_fvp = None
self.compute_vflossandgrad = None
self.d_adam = None
self.vfadam = None
self.get_flat = None
self.set_from_flat = None
self.timed = None
self.allmean = None
self.nworkers = None
self.rank = None
self.reward_giver = None
self.step = None
self.proba_step = None
self.initial_state = None
self.params = None
self.summary = None
if _init_setup_model:
self.setup_model()
def _get_pretrain_placeholders(self):
policy = self.policy_pi
action_ph = policy.pdtype.sample_placeholder([None])
if isinstance(self.action_space, gym.spaces.Discrete):
return policy.obs_ph, action_ph, policy.policy
return policy.obs_ph, action_ph, policy.deterministic_action
[docs] def setup_model(self):
# prevent import loops
from stable_baselines.gail.adversary import TransitionClassifier
with SetVerbosity(self.verbose):
assert issubclass(self.policy, ActorCriticPolicy), "Error: the input policy for the TRPO model must be " \
"an instance of common.policies.ActorCriticPolicy."
self.nworkers = MPI.COMM_WORLD.Get_size()
self.rank = MPI.COMM_WORLD.Get_rank()
np.set_printoptions(precision=3)
self.graph = tf.Graph()
with self.graph.as_default():
self.set_random_seed(self.seed)
self.sess = tf_util.make_session(num_cpu=self.n_cpu_tf_sess, graph=self.graph)
if self.using_gail:
self.reward_giver = TransitionClassifier(self.observation_space, self.action_space,
self.hidden_size_adversary,
entcoeff=self.adversary_entcoeff)
# Construct network for new policy
self.policy_pi = self.policy(self.sess, self.observation_space, self.action_space, self.n_envs, 1,
None, reuse=False, **self.policy_kwargs)
# Network for old policy
with tf.variable_scope("oldpi", reuse=False):
old_policy = self.policy(self.sess, self.observation_space, self.action_space, self.n_envs, 1,
None, reuse=False, **self.policy_kwargs)
with tf.variable_scope("loss", reuse=False):
atarg = tf.placeholder(dtype=tf.float32, shape=[None]) # Target advantage function (if applicable)
ret = tf.placeholder(dtype=tf.float32, shape=[None]) # Empirical return
observation = self.policy_pi.obs_ph
action = self.policy_pi.pdtype.sample_placeholder([None])
kloldnew = old_policy.proba_distribution.kl(self.policy_pi.proba_distribution)
ent = self.policy_pi.proba_distribution.entropy()
meankl = tf.reduce_mean(kloldnew)
meanent = tf.reduce_mean(ent)
entbonus = self.entcoeff * meanent
vferr = tf.reduce_mean(tf.square(self.policy_pi.value_flat - ret))
# advantage * pnew / pold
ratio = tf.exp(self.policy_pi.proba_distribution.logp(action) -
old_policy.proba_distribution.logp(action))
surrgain = tf.reduce_mean(ratio * atarg)
optimgain = surrgain + entbonus
losses = [optimgain, meankl, entbonus, surrgain, meanent]
self.loss_names = ["optimgain", "meankl", "entloss", "surrgain", "entropy"]
dist = meankl
all_var_list = tf_util.get_trainable_vars("model")
var_list = [v for v in all_var_list if "/vf" not in v.name and "/q/" not in v.name]
vf_var_list = [v for v in all_var_list if "/pi" not in v.name and "/logstd" not in v.name]
self.get_flat = tf_util.GetFlat(var_list, sess=self.sess)
self.set_from_flat = tf_util.SetFromFlat(var_list, sess=self.sess)
klgrads = tf.gradients(dist, var_list)
flat_tangent = tf.placeholder(dtype=tf.float32, shape=[None], name="flat_tan")
shapes = [var.get_shape().as_list() for var in var_list]
start = 0
tangents = []
for shape in shapes:
var_size = tf_util.intprod(shape)
tangents.append(tf.reshape(flat_tangent[start: start + var_size], shape))
start += var_size
gvp = tf.add_n([tf.reduce_sum(grad * tangent)
for (grad, tangent) in zipsame(klgrads, tangents)]) # pylint: disable=E1111
# Fisher vector products
fvp = tf_util.flatgrad(gvp, var_list)
tf.summary.scalar('entropy_loss', meanent)
tf.summary.scalar('policy_gradient_loss', optimgain)
tf.summary.scalar('value_function_loss', surrgain)
tf.summary.scalar('approximate_kullback-leibler', meankl)
tf.summary.scalar('loss', optimgain + meankl + entbonus + surrgain + meanent)
self.assign_old_eq_new = \
tf_util.function([], [], updates=[tf.assign(oldv, newv) for (oldv, newv) in
zipsame(tf_util.get_globals_vars("oldpi"),
tf_util.get_globals_vars("model"))])
self.compute_losses = tf_util.function([observation, old_policy.obs_ph, action, atarg], losses)
self.compute_fvp = tf_util.function([flat_tangent, observation, old_policy.obs_ph, action, atarg],
fvp)
self.compute_vflossandgrad = tf_util.function([observation, old_policy.obs_ph, ret],
tf_util.flatgrad(vferr, vf_var_list))
@contextmanager
def timed(msg):
if self.rank == 0 and self.verbose >= 1:
print(colorize(msg, color='magenta'))
start_time = time.time()
yield
print(colorize("done in {:.3f} seconds".format((time.time() - start_time)),
color='magenta'))
else:
yield
def allmean(arr):
assert isinstance(arr, np.ndarray)
out = np.empty_like(arr)
MPI.COMM_WORLD.Allreduce(arr, out, op=MPI.SUM)
out /= self.nworkers
return out
tf_util.initialize(sess=self.sess)
th_init = self.get_flat()
MPI.COMM_WORLD.Bcast(th_init, root=0)
self.set_from_flat(th_init)
with tf.variable_scope("Adam_mpi", reuse=False):
self.vfadam = MpiAdam(vf_var_list, sess=self.sess)
if self.using_gail:
self.d_adam = MpiAdam(self.reward_giver.get_trainable_variables(), sess=self.sess)
self.d_adam.sync()
self.vfadam.sync()
with tf.variable_scope("input_info", reuse=False):
tf.summary.scalar('discounted_rewards', tf.reduce_mean(ret))
tf.summary.scalar('learning_rate', tf.reduce_mean(self.vf_stepsize))
tf.summary.scalar('advantage', tf.reduce_mean(atarg))
tf.summary.scalar('kl_clip_range', tf.reduce_mean(self.max_kl))
if self.full_tensorboard_log:
tf.summary.histogram('discounted_rewards', ret)
tf.summary.histogram('learning_rate', self.vf_stepsize)
tf.summary.histogram('advantage', atarg)
tf.summary.histogram('kl_clip_range', self.max_kl)
if tf_util.is_image(self.observation_space):
tf.summary.image('observation', observation)
else:
tf.summary.histogram('observation', observation)
self.timed = timed
self.allmean = allmean
self.step = self.policy_pi.step
self.proba_step = self.policy_pi.proba_step
self.initial_state = self.policy_pi.initial_state
self.params = tf_util.get_trainable_vars("model") + tf_util.get_trainable_vars("oldpi")
if self.using_gail:
self.params.extend(self.reward_giver.get_trainable_variables())
self.summary = tf.summary.merge_all()
self.compute_lossandgrad = \
tf_util.function([observation, old_policy.obs_ph, action, atarg, ret],
[self.summary, tf_util.flatgrad(optimgain, var_list)] + losses)
def _initialize_dataloader(self):
"""Initialize dataloader."""
batchsize = self.timesteps_per_batch // self.d_step
self.expert_dataset.init_dataloader(batchsize)
[docs] def learn(self, total_timesteps, callback=None, log_interval=100, tb_log_name="TRPO",
reset_num_timesteps=True):
new_tb_log = self._init_num_timesteps(reset_num_timesteps)
callback = self._init_callback(callback)
with SetVerbosity(self.verbose), TensorboardWriter(self.graph, self.tensorboard_log, tb_log_name, new_tb_log) \
as writer:
self._setup_learn()
with self.sess.as_default():
callback.on_training_start(locals(), globals())
seg_gen = traj_segment_generator(self.policy_pi, self.env, self.timesteps_per_batch,
reward_giver=self.reward_giver,
gail=self.using_gail, callback=callback)
episodes_so_far = 0
timesteps_so_far = 0
iters_so_far = 0
t_start = time.time()
len_buffer = deque(maxlen=40) # rolling buffer for episode lengths
reward_buffer = deque(maxlen=40) # rolling buffer for episode rewards
true_reward_buffer = None
if self.using_gail:
true_reward_buffer = deque(maxlen=40)
self._initialize_dataloader()
# Stats not used for now
# TODO: replace with normal tb logging
# g_loss_stats = Stats(loss_names)
# d_loss_stats = Stats(reward_giver.loss_name)
# ep_stats = Stats(["True_rewards", "Rewards", "Episode_length"])
while True:
if timesteps_so_far >= total_timesteps:
break
logger.log("********** Iteration %i ************" % iters_so_far)
def fisher_vector_product(vec):
return self.allmean(self.compute_fvp(vec, *fvpargs, sess=self.sess)) + self.cg_damping * vec
# ------------------ Update G ------------------
logger.log("Optimizing Policy...")
# g_step = 1 when not using GAIL
mean_losses = None
vpredbefore = None
tdlamret = None
observation = None
action = None
seg = None
for k in range(self.g_step):
with self.timed("sampling"):
seg = seg_gen.__next__()
# Stop training early (triggered by the callback)
if not seg.get('continue_training', True): # pytype: disable=attribute-error
break
add_vtarg_and_adv(seg, self.gamma, self.lam)
# ob, ac, atarg, ret, td1ret = map(np.concatenate, (obs, acs, atargs, rets, td1rets))
observation, action = seg["observations"], seg["actions"]
atarg, tdlamret = seg["adv"], seg["tdlamret"]
vpredbefore = seg["vpred"] # predicted value function before update
atarg = (atarg - atarg.mean()) / (atarg.std() + 1e-8) # standardized advantage function estimate
# true_rew is the reward without discount
if writer is not None:
total_episode_reward_logger(self.episode_reward,
seg["true_rewards"].reshape(
(self.n_envs, -1)),
seg["dones"].reshape((self.n_envs, -1)),
writer, self.num_timesteps)
args = seg["observations"], seg["observations"], seg["actions"], atarg
# Subsampling: see p40-42 of John Schulman thesis
# http://joschu.net/docs/thesis.pdf
fvpargs = [arr[::5] for arr in args]
self.assign_old_eq_new(sess=self.sess)
with self.timed("computegrad"):
steps = self.num_timesteps + (k + 1) * (seg["total_timestep"] / self.g_step)
run_options = tf.RunOptions(trace_level=tf.RunOptions.FULL_TRACE)
run_metadata = tf.RunMetadata() if self.full_tensorboard_log else None
# run loss backprop with summary, and save the metadata (memory, compute time, ...)
if writer is not None:
summary, grad, *lossbefore = self.compute_lossandgrad(*args, tdlamret, sess=self.sess,
options=run_options,
run_metadata=run_metadata)
if self.full_tensorboard_log:
writer.add_run_metadata(run_metadata, 'step%d' % steps)
writer.add_summary(summary, steps)
else:
_, grad, *lossbefore = self.compute_lossandgrad(*args, tdlamret, sess=self.sess,
options=run_options,
run_metadata=run_metadata)
lossbefore = self.allmean(np.array(lossbefore))
grad = self.allmean(grad)
if np.allclose(grad, 0):
logger.log("Got zero gradient. not updating")
else:
with self.timed("conjugate_gradient"):
stepdir = conjugate_gradient(fisher_vector_product, grad, cg_iters=self.cg_iters,
verbose=self.rank == 0 and self.verbose >= 1)
assert np.isfinite(stepdir).all()
shs = .5 * stepdir.dot(fisher_vector_product(stepdir))
# abs(shs) to avoid taking square root of negative values
lagrange_multiplier = np.sqrt(abs(shs) / self.max_kl)
# logger.log("lagrange multiplier:", lm, "gnorm:", np.linalg.norm(g))
fullstep = stepdir / lagrange_multiplier
expectedimprove = grad.dot(fullstep)
surrbefore = lossbefore[0]
stepsize = 1.0
thbefore = self.get_flat()
for _ in range(10):
thnew = thbefore + fullstep * stepsize
self.set_from_flat(thnew)
mean_losses = surr, kl_loss, *_ = self.allmean(
np.array(self.compute_losses(*args, sess=self.sess)))
improve = surr - surrbefore
logger.log("Expected: %.3f Actual: %.3f" % (expectedimprove, improve))
if not np.isfinite(mean_losses).all():
logger.log("Got non-finite value of losses -- bad!")
elif kl_loss > self.max_kl * 1.5:
logger.log("violated KL constraint. shrinking step.")
elif improve < 0:
logger.log("surrogate didn't improve. shrinking step.")
else:
logger.log("Stepsize OK!")
break
stepsize *= .5
else:
logger.log("couldn't compute a good step")
self.set_from_flat(thbefore)
if self.nworkers > 1 and iters_so_far % 20 == 0:
# list of tuples
paramsums = MPI.COMM_WORLD.allgather((thnew.sum(), self.vfadam.getflat().sum()))
assert all(np.allclose(ps, paramsums[0]) for ps in paramsums[1:])
for (loss_name, loss_val) in zip(self.loss_names, mean_losses):
logger.record_tabular(loss_name, loss_val)
with self.timed("vf"):
for _ in range(self.vf_iters):
# NOTE: for recurrent policies, use shuffle=False?
for (mbob, mbret) in dataset.iterbatches((seg["observations"], seg["tdlamret"]),
include_final_partial_batch=False,
batch_size=128,
shuffle=True):
grad = self.allmean(self.compute_vflossandgrad(mbob, mbob, mbret, sess=self.sess))
self.vfadam.update(grad, self.vf_stepsize)
# Stop training early (triggered by the callback)
if not seg.get('continue_training', True): # pytype: disable=attribute-error
break
logger.record_tabular("explained_variance_tdlam_before",
explained_variance(vpredbefore, tdlamret))
if self.using_gail:
# ------------------ Update D ------------------
logger.log("Optimizing Discriminator...")
logger.log(fmt_row(13, self.reward_giver.loss_name))
assert len(observation) == self.timesteps_per_batch
batch_size = self.timesteps_per_batch // self.d_step
# NOTE: uses only the last g step for observation
d_losses = [] # list of tuples, each of which gives the loss for a minibatch
# NOTE: for recurrent policies, use shuffle=False?
for ob_batch, ac_batch in dataset.iterbatches((observation, action),
include_final_partial_batch=False,
batch_size=batch_size,
shuffle=True):
ob_expert, ac_expert = self.expert_dataset.get_next_batch()
# update running mean/std for reward_giver
if self.reward_giver.normalize:
self.reward_giver.obs_rms.update(np.concatenate((ob_batch, ob_expert), 0))
# Reshape actions if needed when using discrete actions
if isinstance(self.action_space, gym.spaces.Discrete):
if len(ac_batch.shape) == 2:
ac_batch = ac_batch[:, 0]
if len(ac_expert.shape) == 2:
ac_expert = ac_expert[:, 0]
*newlosses, grad = self.reward_giver.lossandgrad(ob_batch, ac_batch, ob_expert, ac_expert)
self.d_adam.update(self.allmean(grad), self.d_stepsize)
d_losses.append(newlosses)
logger.log(fmt_row(13, np.mean(d_losses, axis=0)))
# lr: lengths and rewards
lr_local = (seg["ep_lens"], seg["ep_rets"], seg["ep_true_rets"]) # local values
list_lr_pairs = MPI.COMM_WORLD.allgather(lr_local) # list of tuples
lens, rews, true_rets = map(flatten_lists, zip(*list_lr_pairs))
true_reward_buffer.extend(true_rets)
else:
# lr: lengths and rewards
lr_local = (seg["ep_lens"], seg["ep_rets"]) # local values
list_lr_pairs = MPI.COMM_WORLD.allgather(lr_local) # list of tuples
lens, rews = map(flatten_lists, zip(*list_lr_pairs))
len_buffer.extend(lens)
reward_buffer.extend(rews)
if len(len_buffer) > 0:
logger.record_tabular("EpLenMean", np.mean(len_buffer))
logger.record_tabular("EpRewMean", np.mean(reward_buffer))
if self.using_gail:
logger.record_tabular("EpTrueRewMean", np.mean(true_reward_buffer))
logger.record_tabular("EpThisIter", len(lens))
episodes_so_far += len(lens)
current_it_timesteps = MPI.COMM_WORLD.allreduce(seg["total_timestep"])
timesteps_so_far += current_it_timesteps
self.num_timesteps += current_it_timesteps
iters_so_far += 1
logger.record_tabular("EpisodesSoFar", episodes_so_far)
logger.record_tabular("TimestepsSoFar", self.num_timesteps)
logger.record_tabular("TimeElapsed", time.time() - t_start)
if self.verbose >= 1 and self.rank == 0:
logger.dump_tabular()
callback.on_training_end()
return self
[docs] def save(self, save_path, cloudpickle=False):
data = {
"gamma": self.gamma,
"timesteps_per_batch": self.timesteps_per_batch,
"max_kl": self.max_kl,
"cg_iters": self.cg_iters,
"lam": self.lam,
"entcoeff": self.entcoeff,
"cg_damping": self.cg_damping,
"vf_stepsize": self.vf_stepsize,
"vf_iters": self.vf_iters,
"hidden_size_adversary": self.hidden_size_adversary,
"adversary_entcoeff": self.adversary_entcoeff,
"expert_dataset": self.expert_dataset,
"g_step": self.g_step,
"d_step": self.d_step,
"d_stepsize": self.d_stepsize,
"using_gail": self.using_gail,
"verbose": self.verbose,
"policy": self.policy,
"observation_space": self.observation_space,
"action_space": self.action_space,
"n_envs": self.n_envs,
"n_cpu_tf_sess": self.n_cpu_tf_sess,
"seed": self.seed,
"_vectorize_action": self._vectorize_action,
"policy_kwargs": self.policy_kwargs
}
params_to_save = self.get_parameters()
self._save_to_file(save_path, data=data, params=params_to_save, cloudpickle=cloudpickle)