import os.path as osp
import time
import joblib
import numpy as np
import tensorflow as tf
from baselines import logger
from baselines.common import set_global_seeds, explained_variance
from baselines.common.runners import AbstractEnvRunner
from baselines.common import tf_util
from baselines.a2c.utils import discount_with_dones
from baselines.a2c.utils import Scheduler, make_path, find_trainable_variables
from baselines.a2c.utils import cat_entropy, mse
class Model(object):
def __init__(self, policy, ob_space, ac_space, nenvs, nsteps,
ent_coef=0.01, vf_coef=0.5, max_grad_norm=0.5, lr=7e-4,
alpha=0.99, epsilon=1e-5, total_timesteps=int(80e6), lrschedule='linear'):
sess = tf_util.make_session()
nbatch = nenvs*nsteps
A = tf.placeholder(tf.int32, [nbatch])
ADV = tf.placeholder(tf.float32, [nbatch])
R = tf.placeholder(tf.float32, [nbatch])
LR = tf.placeholder(tf.float32, [])
step_model = policy(sess, ob_space, ac_space, nenvs, 1, reuse=False)
train_model = policy(sess, ob_space, ac_space, nenvs*nsteps, nsteps, reuse=True)
neglogpac = tf.nn.sparse_softmax_cross_entropy_with_logits(logits=train_model.pi, labels=A)
pg_loss = tf.reduce_mean(ADV * neglogpac)
vf_loss = tf.reduce_mean(mse(tf.squeeze(train_model.vf), R))
entropy = tf.reduce_mean(cat_entropy(train_model.pi))
loss = pg_loss - entropy*ent_coef + vf_loss * vf_coef
params = find_trainable_variables("model")
grads = tf.gradients(loss, params)
if max_grad_norm is not None:
grads, grad_norm = tf.clip_by_global_norm(grads, max_grad_norm)
grads = list(zip(grads, params))
trainer = tf.train.RMSPropOptimizer(learning_rate=LR, decay=alpha, epsilon=epsilon)
_train = trainer.apply_gradients(grads)
lr = Scheduler(v=lr, nvalues=total_timesteps, schedule=lrschedule)
def train(obs, states, rewards, masks, actions, values):
advs = rewards - values
for step in range(len(obs)):
cur_lr = lr.value()
td_map = {train_model.X:obs, A:actions, ADV:advs, R:rewards, LR:cur_lr}
if states is not None:
td_map[train_model.S] = states
td_map[train_model.M] = masks
policy_loss, value_loss, policy_entropy, _ = sess.run(
[pg_loss, vf_loss, entropy, _train],
td_map
)
return policy_loss, value_loss, policy_entropy
def save(save_path):
ps = sess.run(params)
make_path(osp.dirname(save_path))
joblib.dump(ps, save_path)
def load(load_path):
loaded_params = joblib.load(load_path)
restores = []
for p, loaded_p in zip(params, loaded_params):
restores.append(p.assign(loaded_p))
sess.run(restores)
self.train = train
self.train_model = train_model
self.step_model = step_model
self.step = step_model.step
self.value = step_model.value
self.initial_state = step_model.initial_state
self.save = save
self.load = load
tf.global_variables_initializer().run(session=sess)
class Runner(AbstractEnvRunner):
def __init__(self, env, model, nsteps=5, gamma=0.99):
super().__init__(env=env, model=model, nsteps=nsteps)
self.gamma = gamma
def run(self):
mb_obs, mb_rewards, mb_actions, mb_values, mb_dones = [],[],[],[],[]
mb_states = self.states
for n in range(self.nsteps):
actions, values, states, _ = self.model.step(self.obs, self.states, self.dones)
mb_obs.append(np.copy(self.obs))
mb_actions.append(actions)
mb_values.append(values)
mb_dones.append(self.dones)
obs, rewards, dones, _ = self.env.step(actions)
self.states = states
self.dones = dones
for n, done in enumerate(dones):
if done:
self.obs[n] = self.obs[n]*0
self.obs = obs
mb_rewards.append(rewards)
mb_dones.append(self.dones)
#batch of steps to batch of rollouts
mb_obs = np.asarray(mb_obs, dtype=np.uint8).swapaxes(1, 0).reshape(self.batch_ob_shape)
mb_rewards = np.asarray(mb_rewards, dtype=np.float32).swapaxes(1, 0)
mb_actions = np.asarray(mb_actions, dtype=np.int32).swapaxes(1, 0)
mb_values = np.asarray(mb_values, dtype=np.float32).swapaxes(1, 0)
mb_dones = np.asarray(mb_dones, dtype=np.bool).swapaxes(1, 0)
mb_masks = mb_dones[:, :-1]
mb_dones = mb_dones[:, 1:]
last_values = self.model.value(self.obs, self.states, self.dones).tolist()
#discount/bootstrap off value fn
for n, (rewards, dones, value) in enumerate(zip(mb_rewards, mb_dones, last_values)):
rewards = rewards.tolist()
dones = dones.tolist()
if dones[-1] == 0:
rewards = discount_with_dones(rewards+[value], dones+[0], self.gamma)[:-1]
else:
rewards = discount_with_dones(rewards, dones, self.gamma)
mb_rewards[n] = rewards
mb_rewards = mb_rewards.flatten()
mb_actions = mb_actions.flatten()
mb_values = mb_values.flatten()
mb_masks = mb_masks.flatten()
return mb_obs, mb_states, mb_rewards, mb_masks, mb_actions, mb_values
def learn(policy, env, seed, nsteps=5, total_timesteps=int(80e6), vf_coef=0.5, ent_coef=0.01, max_grad_norm=0.5, lr=7e-4, lrschedule='linear', epsilon=1e-5, alpha=0.99, gamma=0.99, log_interval=100):
set_global_seeds(seed)
nenvs = env.num_envs
ob_space = env.observation_space
ac_space = env.action_space
model = Model(policy=policy, ob_space=ob_space, ac_space=ac_space, nenvs=nenvs, nsteps=nsteps, ent_coef=ent_coef, vf_coef=vf_coef,
max_grad_norm=max_grad_norm, lr=lr, alpha=alpha, epsilon=epsilon, total_timesteps=total_timesteps, lrschedule=lrschedule)
runner = Runner(env, model, nsteps=nsteps, gamma=gamma)
nbatch = nenvs*nsteps
tstart = time.time()
for update in range(1, total_timesteps//nbatch+1):
obs, states, rewards, masks, actions, values = runner.run()
policy_loss, value_loss, policy_entropy = model.train(obs, states, rewards, masks, actions, values)
nseconds = time.time()-tstart
fps = int((update*nbatch)/nseconds)
if update % log_interval == 0 or update == 1:
ev = explained_variance(values, rewards)
logger.record_tabular("nupdates", update)
logger.record_tabular("total_timesteps", update*nbatch)
logger.record_tabular("fps", fps)
logger.record_tabular("policy_entropy", float(policy_entropy))
logger.record_tabular("value_loss", float(value_loss))
logger.record_tabular("explained_variance", float(ev))
logger.dump_tabular()
env.close()
return model
Datasets
Models
