def ppo(
env_fn,
actor_critic=core.ActorCritic,
ac_kwargs=dict(),
seed=0,
steps_per_epoch=4000,
epochs=50,
gamma=0.99,
clip_ratio=0.2,
pi_lr=3e-4,
vf_lr=1e-3,
train_pi_iters=80,
train_v_iters=80,
lam=0.97,
max_ep_len=1000,
target_kl=0.01,
logger_kwargs=dict(),
save_freq=10,
use_gpu=False,
gpu_parallel=False,
):
"""
Args:
env_fn : A function which creates a copy of the environment.
The environment must satisfy the OpenAI Gym API.
actor_critic: The agent's main model which is composed of
the policy and value function model, where the policy takes
some state, ``x`` and action ``a``, and value function takes
the state ``x``. The model returns a tuple of:
=========== ================ ======================================
Symbol Shape Description
=========== ================ ======================================
``pi`` (batch, act_dim) | Samples actions from policy given
| states.
``logp`` (batch,) | Gives log probability, according to
| the policy, of taking actions ``a``
| in states ``x``.
``logp_pi`` (batch,) | Gives log probability, according to
| the policy, of the action sampled by
| ``pi``.
``v`` (batch,) | Gives the value estimate for states
| in ``x``. (Critical: make sure
| to flatten this via .squeeze()!)
=========== ================ ======================================
ac_kwargs (dict): Any kwargs appropriate for the actor_critic
class you provided to PPO.
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 of interaction (equivalent to
number of policy updates) to perform.
gamma (float): Discount factor. (Always between 0 and 1.)
clip_ratio (float): Hyperparameter for clipping in the policy objective.
Roughly: how far can the new policy go from the old policy while
still profiting (improving the objective function)? The new policy
can still go farther than the clip_ratio says, but it doesn't help
on the objective anymore. (Usually small, 0.1 to 0.3.)
pi_lr (float): Learning rate for policy optimizer.
vf_lr (float): Learning rate for value function optimizer.
train_pi_iters (int): Maximum number of gradient descent steps to take
on policy loss per epoch. (Early stopping may cause optimizer
to take fewer than this.)
train_v_iters (int): Number of gradient descent steps to take on
value function per epoch.
lam (float): Lambda for GAE-Lambda. (Always between 0 and 1,
close to 1.)
max_ep_len (int): Maximum length of trajectory / episode / rollout.
target_kl (float): Roughly what KL divergence we think is appropriate
between new and old policies after an update. This will get used
for early stopping. (Usually small, 0.01 or 0.05.)
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())
seed += 10000 * proc_id()
torch.manual_seed(seed)
np.random.seed(seed)
env = env_fn()
obs_dim = env.observation_space.shape
act_dim = env.action_space.shape
# Share information about action space with policy architecture
ac_kwargs['action_space'] = env.action_space
# Main model
actor_critic = actor_critic(in_features=obs_dim[0], **ac_kwargs)
# actor_critic = torch.nn.DataParallel(actor_critic).to(device)
# gpu是否使用
# device = torch.device("cpu" if USE_DEVICE=="cpu" else "cuda")
if torch.cuda.is_available():
device = torch.device("cuda" if use_gpu else "cpu")
if gpu_parallel:
actor_critic = torch.nn.DataParallel(actor_critic)
else:
use_gpu = False
use_parallel = False
device = torch.device("cpu")
actor_critic = actor_critic.to(device)
# Experience buffer
local_steps_per_epoch = int(steps_per_epoch / num_procs())
buf = PPOBuffer(obs_dim, act_dim, local_steps_per_epoch, gamma, lam)
# Count variables
var_counts = tuple(
core.count_vars(module)
for module in [actor_critic.policy, actor_critic.value_function])
logger.log('\nNumber of parameters: \t pi: %d, \t v: %d\n' % var_counts)
# Optimizers
train_pi = torch.optim.Adam(actor_critic.policy.parameters(), lr=pi_lr)
train_v = torch.optim.Adam(actor_critic.value_function.parameters(),
lr=vf_lr)
# Sync params across processes
sync_all_params(actor_critic.parameters())
def update():
temp_get = buf.get()
obs, act, adv, ret, logp_old = [
torch.Tensor(x).to(device) for x in temp_get
]
# Training policy
_, logp, _ = actor_critic.policy(obs, act)
ratio = (logp - logp_old).exp()
min_adv = torch.where(adv > 0, (1 + clip_ratio) * adv,
(1 - clip_ratio) * adv)
pi_l_old = -(torch.min(ratio * adv, min_adv)).mean()
ent = (-logp).mean() # a sample estimate for entropy
for i in range(train_pi_iters):
# Output from policy function graph
_, logp, _ = actor_critic.policy(obs, act)
# PPO policy objective
ratio = (logp - logp_old).exp()
min_adv = torch.where(adv > 0, (1 + clip_ratio) * adv,
(1 - clip_ratio) * adv)
pi_loss = -(torch.min(ratio * adv, min_adv)).mean()
# Policy gradient step
train_pi.zero_grad()
pi_loss.backward()
average_gradients(train_pi.param_groups)
train_pi.step()
_, logp, _ = actor_critic.policy(obs, act)
kl = (logp_old - logp).mean()
kl = mpi_avg(kl.item())
if kl > 1.5 * target_kl:
logger.log(
'Early stopping at step %d due to reaching max kl.' % i)
break
logger.store(StopIter=i)
# Training value function
v = actor_critic.value_function(obs)
v_l_old = F.mse_loss(v, ret)
for _ in range(train_v_iters):
# Output from value function graph
v = actor_critic.value_function(obs)
# PPO value function objective
v_loss = F.mse_loss(v, ret)
# Value function gradient step
train_v.zero_grad()
v_loss.backward()
average_gradients(train_v.param_groups)
train_v.step()
# Log changes from update
_, logp, _, v = actor_critic(obs, act)
ratio = (logp - logp_old).exp()
min_adv = torch.where(adv > 0, (1 + clip_ratio) * adv,
(1 - clip_ratio) * adv)
pi_l_new = -(torch.min(ratio * adv, min_adv)).mean()
v_l_new = F.mse_loss(v, ret)
kl = (logp_old - logp).mean() # a sample estimate for KL-divergence
clipped = (ratio > (1 + clip_ratio)) | (ratio < (1 - clip_ratio))
cf = (clipped.float()).mean()
logger.store(LossPi=pi_l_old,
LossV=v_l_old,
KL=kl,
Entropy=ent,
ClipFrac=cf,
DeltaLossPi=(pi_l_new - pi_l_old),
DeltaLossV=(v_l_new - v_l_old))
start_time = time.time()
o, r, d, ep_ret, ep_len = env.reset(), 0, False, 0, 0
# Main loop: collect experience in env and update/log each epoch
for epoch in range(epochs):
actor_critic.eval()
for t in range(local_steps_per_epoch):
a, _, logp_t, v_t = actor_critic(
torch.Tensor(o.reshape(1, -1)).to(device))
# save and log
buf.store(o,
a.cpu().detach().numpy(), r, v_t.item(),
logp_t.cpu().detach().numpy())
logger.store(VVals=v_t)
o, r, d, _ = env.step(a.cpu().detach().numpy()[0])
ep_ret += r
ep_len += 1
terminal = d or (ep_len == max_ep_len)
if terminal or (t == local_steps_per_epoch - 1):
if not (terminal):
print('Warning: trajectory cut off by epoch at %d steps.' %
ep_len)
# if trajectory didn't reach terminal state, bootstrap value target
last_val = r if d else actor_critic.value_function(
torch.Tensor(o.reshape(1, -1)).to(device)).item()
buf.finish_path(last_val)
if terminal:
# only save EpRet / EpLen if trajectory finished
logger.store(EpRet=ep_ret, EpLen=ep_len)
o, r, d, ep_ret, ep_len = env.reset(), 0, False, 0, 0
# Save model
if (epoch % save_freq == 0) or (epoch == epochs - 1):
logger.save_state({'env': env}, actor_critic, None)
# Perform PPO update!
actor_critic.train()
update()
# Log info about epoch
logger.log_tabular('Epoch', epoch)
logger.log_tabular('EpRet', with_min_and_max=True)
logger.log_tabular('EpLen', average_only=True)
logger.log_tabular('VVals', with_min_and_max=True)
logger.log_tabular('TotalEnvInteracts', (epoch + 1) * steps_per_epoch)
logger.log_tabular('LossPi', average_only=True)
logger.log_tabular('LossV', average_only=True)
logger.log_tabular('DeltaLossPi', average_only=True)
logger.log_tabular('DeltaLossV', average_only=True)
logger.log_tabular('Entropy', average_only=True)
logger.log_tabular('KL', average_only=True)
logger.log_tabular('ClipFrac', average_only=True)
logger.log_tabular('StopIter', average_only=True)
logger.log_tabular('Time', time.time() - start_time)
logger.dump_tabular()
def trpo(
env_fn,
actor_critic=core.ActorCritic,
ac_kwargs=dict(),
seed=0,
steps_per_epoch=4000,
epochs=50,
gamma=0.99,
delta=0.01,
vf_lr=1e-3,
train_v_iters=80,
damping_coeff=0.1,
cg_iters=10,
backtrack_iters=10,
backtrack_coeff=0.8,
lam=0.97,
max_ep_len=1000,
logger_kwargs=dict(),
save_freq=10,
algo="trpo",
):
"""
Args:
env_fn : A function which creates a copy of the environment.
The environment must satisfy the OpenAI Gym API.
actor_critic: The agent's main model which for state ``x`` and
action, ``a`` returns the following outputs:
============ ================ ========================================
Symbol Shape Description
============ ================ ========================================
``pi`` (batch, act_dim) | Samples actions from policy given
| states.
``logp`` (batch,) | Gives log probability, according to
| the policy, of taking actions ``a``
| in states ``x``.
``logp_pi`` (batch,) | Gives log probability, according to
| the policy, of the action sampled by
| ``pi``.
``info`` N/A | A dict of any intermediate quantities
| (from calculating the policy or log
| probabilities) which are needed for
| analytically computing KL divergence.
| (eg sufficient statistics of the
| distributions)
``info_phs`` N/A | A dict of placeholders for old values
| of the entries in ``info``.
``d_kl`` () | The mean KL
| divergence between the current policy
| (``pi``) and the old policy (as
| specified by the inputs to
| ``info``) over the batch of
| states given in ``x``.
``v`` (batch,) | Gives the value estimate for states
| in ``x``. (Critical: make sure
| to flatten this!)
============ ================ ========================================
ac_kwargs (dict): Any kwargs appropriate for the actor_critic
function you provided to TRPO.
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 of interaction (equivalent to
number of policy updates) to perform.
gamma (float): Discount factor. (Always between 0 and 1.)
delta (float): KL-divergence limit for TRPO / NPG update.
(Should be small for stability. Values like 0.01, 0.05.)
vf_lr (float): Learning rate for value function optimizer.
train_v_iters (int): Number of gradient descent steps to take on
value function per epoch.
damping_coeff (float): Artifact for numerical stability, should be
smallish. Adjusts Hessian-vector product calculation:
.. math:: Hv \\rightarrow (\\alpha I + H)v
where :math:`\\alpha` is the damping coefficient.
Probably don't play with this hyperparameter.
cg_iters (int): Number of iterations of conjugate gradient to perform.
Increasing this will lead to a more accurate approximation
to :math:`H^{-1} g`, and possibly slightly-improved performance,
but at the cost of slowing things down.
Also probably don't play with this hyperparameter.
backtrack_iters (int): Maximum number of steps allowed in the
backtracking line search. Since the line search usually doesn't
backtrack, and usually only steps back once when it does, this
hyperparameter doesn't often matter.
backtrack_coeff (float): How far back to step during backtracking line
search. (Always between 0 and 1, usually above 0.5.)
lam (float): Lambda for GAE-Lambda. (Always between 0 and 1,
close to 1.)
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.
algo: Either 'trpo' or 'npg': this code supports both, since they are
almost the same.
"""
setup_pytorch_for_mpi()
logger = EpochLogger(**logger_kwargs)
logger.save_config(locals())
seed += 10000 * proc_id()
torch.manual_seed(seed)
np.random.seed(seed)
env = env_fn()
obs_dim = env.observation_space.shape
act_dim = env.action_space.shape
# Share information about action space with policy architecture
ac_kwargs["action_space"] = env.action_space
# Main model
actor_critic = actor_critic(in_features=obs_dim[0], **ac_kwargs)
# Experience buffer
local_steps_per_epoch = int(steps_per_epoch / num_procs())
if isinstance(env.action_space, Box):
info_shapes = {
"old_mu": [env.action_space.shape[-1]],
"old_log_std": [env.action_space.shape[-1]],
}
else:
info_shapes = {"old_logits": [env.action_space.n]}
buf = GAEBuffer(obs_dim, act_dim, local_steps_per_epoch, info_shapes,
gamma, lam)
# Count variables
var_counts = tuple(
core.count_vars(module)
for module in [actor_critic.policy, actor_critic.value_function])
logger.log("\nNumber of parameters: \t pi: %d, \t v: %d\n" % var_counts)
# Optimizer for value function
train_vf = torch.optim.Adam(actor_critic.value_function.parameters(),
lr=vf_lr)
# Sync params across processes
sync_all_params(actor_critic.parameters())
def cg(Ax, b):
"""
Conjugate gradient algorithm
(see https://en.wikipedia.org/wiki/Conjugate_gradient_method)
"""
x = torch.zeros_like(b)
r = b # Note: should be 'b - Ax(x)', but for x=0, Ax(x)=0. Change if doing warm start.
p = b
r_dot_old = torch.dot(r, r)
for _ in range(cg_iters):
z = Ax(p)
alpha = r_dot_old / (torch.dot(p, z) + EPS)
x += alpha * p
r -= alpha * z
r_dot_new = torch.dot(r, r)
p = r + (r_dot_new / r_dot_old) * p
r_dot_old = r_dot_new
return x
def update():
inputs = [torch.Tensor(x) for x in buf.get()]
obs, act, adv, ret, logp_old = inputs[:-len(buf.sorted_info_keys)]
policy_args = dict(
zip(buf.sorted_info_keys, inputs[-len(buf.sorted_info_keys):]))
# Main outputs from computation graph
_, logp, _, _, d_kl, v = actor_critic(obs, act, **policy_args)
# Prepare hessian func, gradient eval
ratio = (logp - logp_old).exp() # pi(a|s) / pi_old(a|s)
pi_l_old = -(ratio * adv).mean()
v_l_old = F.mse_loss(v, ret)
g = core.flat_grad(pi_l_old,
actor_critic.policy.parameters(),
retain_graph=True)
g = torch.from_numpy(mpi_avg(g.numpy()))
pi_l_old = mpi_avg(pi_l_old.item())
def Hx(x):
hvp = core.hessian_vector_product(d_kl, actor_critic.policy, x)
if damping_coeff > 0:
hvp += damping_coeff * x
return torch.from_numpy(mpi_avg(hvp.numpy()))
# Core calculations for TRPO or NPG
x = cg(Hx, g)
alpha = torch.sqrt(2 * delta / (torch.dot(x, Hx(x)) + EPS))
old_params = parameters_to_vector(actor_critic.policy.parameters())
def set_and_eval(step):
vector_to_parameters(old_params - alpha * x * step,
actor_critic.policy.parameters())
_, logp, _, _, d_kl = actor_critic.policy(obs, act, **policy_args)
ratio = (logp - logp_old).exp()
pi_loss = -(ratio * adv).mean()
return mpi_avg(d_kl.item()), mpi_avg(pi_loss.item())
if algo == "npg":
kl, pi_l_new = set_and_eval(step=1.0)
elif algo == "trpo":
for j in range(backtrack_iters):
kl, pi_l_new = set_and_eval(step=backtrack_coeff**j)
if kl <= delta and pi_l_new <= pi_l_old:
logger.log(
"Accepting new params at step %d of line search." % j)
logger.store(BacktrackIters=j)
break
if j == backtrack_iters - 1:
logger.log("Line search failed! Keeping old params.")
logger.store(BacktrackIters=j)
kl, pi_l_new = set_and_eval(step=0.0)
# Value function updates
for _ in range(train_v_iters):
v = actor_critic.value_function(obs)
v_loss = F.mse_loss(v, ret)
# Value function gradient step
train_vf.zero_grad()
v_loss.backward()
average_gradients(train_vf.param_groups)
train_vf.step()
v = actor_critic.value_function(obs)
v_l_new = F.mse_loss(v, ret)
# Log changes from update
logger.store(
LossPi=pi_l_old,
LossV=v_l_old,
KL=kl,
DeltaLossPi=(pi_l_new - pi_l_old),
DeltaLossV=(v_l_new - v_l_old),
)
start_time = time.time()
o, r, d, ep_ret, ep_len = env.reset(), 0, False, 0, 0
# Main loop: collect experience in env and update/log each epoch
for epoch in range(epochs):
actor_critic.eval()
for t in range(local_steps_per_epoch):
a, _, logp_t, info_t, _, v_t = actor_critic(
torch.Tensor(o.reshape(1, -1)))
# save and log
buf.store(
o,
a.detach().numpy(),
r,
v_t.item(),
logp_t.detach().numpy(),
core.values_as_sorted_list(info_t),
)
logger.store(VVals=v_t)
o, r, d, _ = env.step(a.detach().numpy()[0])
ep_ret += r
ep_len += 1
terminal = d or (ep_len == max_ep_len)
if terminal or (t == local_steps_per_epoch - 1):
if not (terminal):
print("Warning: trajectory cut off by epoch at %d steps." %
ep_len)
# if trajectory didn't reach terminal state, bootstrap value target
last_val = (r if d else actor_critic.value_function(
torch.Tensor(o.reshape(1, -1))).item())
buf.finish_path(last_val)
if terminal:
# only save EpRet / EpLen if trajectory finished
logger.store(EpRet=ep_ret, EpLen=ep_len)
o, r, d, ep_ret, ep_len = env.reset(), 0, False, 0, 0
# Save model
if (epoch % save_freq == 0) or (epoch == epochs - 1):
logger.save_state({"env": env}, actor_critic, None)
# Perform TRPO or NPG update!
actor_critic.train()
update()
# Log info about epoch
logger.log_tabular("Epoch", epoch)
logger.log_tabular("EpRet", with_min_and_max=True)
logger.log_tabular("EpLen", average_only=True)
logger.log_tabular("VVals", with_min_and_max=True)
logger.log_tabular("TotalEnvInteracts", (epoch + 1) * steps_per_epoch)
logger.log_tabular("LossPi", average_only=True)
logger.log_tabular("LossV", average_only=True)
logger.log_tabular("DeltaLossPi", average_only=True)
logger.log_tabular("DeltaLossV", average_only=True)
logger.log_tabular("KL", average_only=True)
if algo == "trpo":
logger.log_tabular("BacktrackIters", average_only=True)
logger.log_tabular("Time", time.time() - start_time)
logger.dump_tabular()
def vpg(env_fn,
actor_critic=core.ActorCritic,
ac_kwargs=dict(),
seed=0,
steps_per_epoch=4000,
epochs=50,
gamma=0.99,
pi_lr=3e-4,
vf_lr=1e-3,
train_v_iters=80,
lam=0.97,
max_ep_len=1000,
logger_kwargs=dict(),
save_freq=10):
"""
Args:
env_fn : A function which creates a copy of the environment.
The environment must satisfy the OpenAI Gym API.
actor_critic: The agent's main model which is composed of
the policy and value function model, where the policy takes
some state, ``x``, and action, ``a``, and value function takes
the state ``x`` and returns a tuple of:
=========== ================ ======================================
Symbol Shape Description
=========== ================ ======================================
``pi`` (batch, act_dim) | Samples actions from policy given
| states.
``logp`` (batch,) | Gives log probability, according to
| the policy, of taking actions ``a``
| in states ``x``.
``logp_pi`` (batch,) | Gives log probability, according to
| the policy, of the action sampled by
| ``pi``.
``v`` (batch,) | Gives the value estimate for states
| in ``x``. (Critical: make sure
| to flatten this via .item()!)
=========== ================ ======================================
ac_kwargs (dict): Any kwargs appropriate for the actor_critic
class you provided to VPG.
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 of interaction (equivalent to
number of policy updates) to perform.
gamma (float): Discount factor. (Always between 0 and 1.)
pi_lr (float): Learning rate for policy optimizer.
vf_lr (float): Learning rate for value function optimizer.
train_v_iters (int): Number of gradient descent steps to take on
value function per epoch.
lam (float): Lambda for GAE-Lambda. (Always between 0 and 1,
close to 1.)
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())
seed += 10000 * proc_id()
torch.manual_seed(seed)
np.random.seed(seed)
env = env_fn()
obs_dim = env.observation_space.shape
act_dim = env.action_space.shape
# Share information about action space with policy architecture
ac_kwargs['action_space'] = env.action_space
# Main model
actor_critic = actor_critic(in_features=obs_dim[0], **ac_kwargs)
# Experience buffer
local_steps_per_epoch = int(steps_per_epoch / num_procs())
buf = VPGBuffer(obs_dim, act_dim, local_steps_per_epoch, gamma, lam)
# Count variables
var_counts = tuple(
core.count_vars(module)
for module in [actor_critic.policy, actor_critic.value_function])
logger.log('\nNumber of parameters: \t pi: %d, \t v: %d\n' % var_counts)
# Optimizers
train_pi = torch.optim.Adam(actor_critic.policy.parameters(), lr=pi_lr)
train_v = torch.optim.Adam(actor_critic.value_function.parameters(),
lr=vf_lr)
# Sync params across processes
sync_all_params(actor_critic.parameters())
def update():
obs, act, adv, ret, logp_old = [torch.Tensor(x) for x in buf.get()]
# Policy gradient step
_, logp, _ = actor_critic.policy(obs, act)
ent = (-logp).mean() # a sample estimate for entropy
# VPG policy objective
pi_loss = -(logp * adv).mean()
# Policy gradient step
train_pi.zero_grad()
pi_loss.backward()
average_gradients(train_pi.param_groups)
train_pi.step()
# Value function learning
v = actor_critic.value_function(obs)
v_l_old = F.mse_loss(v, ret)
for _ in range(train_v_iters):
# Output from value function graph
v = actor_critic.value_function(obs)
# VPG value objective
v_loss = F.mse_loss(v, ret)
# Value function gradient step
train_v.zero_grad()
v_loss.backward()
average_gradients(train_v.param_groups)
train_v.step()
# Log changes from update
_, logp, _, v = actor_critic(obs, act)
pi_l_new = -(logp * adv).mean()
v_l_new = F.mse_loss(v, ret)
kl = (logp_old - logp).mean() # a sample estimate for KL-divergence
logger.store(LossPi=pi_loss,
LossV=v_l_old,
KL=kl,
Entropy=ent,
DeltaLossPi=(pi_l_new - pi_loss),
DeltaLossV=(v_l_new - v_l_old))
start_time = time.time()
o, r, d, ep_ret, ep_len = env.reset(), 0, False, 0, 0
# Main loop: collect experience in env and update/log each epoch
for epoch in range(epochs):
actor_critic.eval()
for t in range(local_steps_per_epoch):
a, _, logp_t, v_t = actor_critic(torch.Tensor(o.reshape(1, -1)))
# save and log
buf.store(o,
a.detach().numpy(), r, v_t.item(),
logp_t.detach().numpy())
logger.store(VVals=v_t)
o, r, d, _ = env.step(a.detach().numpy()[0])
ep_ret += r
ep_len += 1
terminal = d or (ep_len == max_ep_len)
if terminal or (t == local_steps_per_epoch - 1):
if not (terminal):
print('Warning: trajectory cut off by epoch at %d steps.' %
ep_len)
# if trajectory didn't reach terminal state, bootstrap value target
last_val = r if d else actor_critic.value_function(
torch.Tensor(o.reshape(1, -1))).item()
buf.finish_path(last_val)
if terminal:
# only save EpRet / EpLen if trajectory finished
logger.store(EpRet=ep_ret, EpLen=ep_len)
o, r, d, ep_ret, ep_len = env.reset(), 0, False, 0, 0
# Save model
if (epoch % save_freq == 0) or (epoch == epochs - 1):
logger.save_state({'env': env}, actor_critic, None)
# Perform VPG update!
actor_critic.train()
update()
# Log info about epoch
logger.log_tabular('Epoch', epoch)
logger.log_tabular('EpRet', with_min_and_max=True)
logger.log_tabular('EpLen', average_only=True)
logger.log_tabular('VVals', with_min_and_max=True)
logger.log_tabular('TotalEnvInteracts', (epoch + 1) * steps_per_epoch)
logger.log_tabular('LossPi', average_only=True)
logger.log_tabular('LossV', average_only=True)
logger.log_tabular('DeltaLossPi', average_only=True)
logger.log_tabular('DeltaLossV', average_only=True)
logger.log_tabular('Entropy', average_only=True)
logger.log_tabular('KL', average_only=True)
logger.log_tabular('Time', time.time() - start_time)
logger.dump_tabular()