import time
import torch
import warnings
import numpy as np
from tianshou.env import BaseVectorEnv
from tianshou.data import Batch, ReplayBuffer, \
ListReplayBuffer
from tianshou.utils import MovAvg
[docs]class Collector(object):
"""The :class:`~tianshou.data.Collector` enables the policy to interact
with different types of environments conveniently.
:param policy: an instance of the :class:`~tianshou.policy.BasePolicy`
class.
:param env: an environment or an instance of the
:class:`~tianshou.env.BaseVectorEnv` class.
:param buffer: an instance of the :class:`~tianshou.data.ReplayBuffer`
class, or a list of :class:`~tianshou.data.ReplayBuffer`. If set to
``None``, it will automatically assign a small-size
:class:`~tianshou.data.ReplayBuffer`.
:param int stat_size: for the moving average of recording speed, defaults
to 100.
:param bool store_obs_next: whether to store the obs_next to replay
buffer, defaults to ``True``.
Example:
::
policy = PGPolicy(...) # or other policies if you wish
env = gym.make('CartPole-v0')
replay_buffer = ReplayBuffer(size=10000)
# here we set up a collector with a single environment
collector = Collector(policy, env, buffer=replay_buffer)
# the collector supports vectorized environments as well
envs = VectorEnv([lambda: gym.make('CartPole-v0') for _ in range(3)])
buffers = [ReplayBuffer(size=5000) for _ in range(3)]
# you can also pass a list of replay buffer to collector, for multi-env
# collector = Collector(policy, envs, buffer=buffers)
collector = Collector(policy, envs, buffer=replay_buffer)
# collect at least 3 episodes
collector.collect(n_episode=3)
# collect 1 episode for the first env, 3 for the third env
collector.collect(n_episode=[1, 0, 3])
# collect at least 2 steps
collector.collect(n_step=2)
# collect episodes with visual rendering (the render argument is the
# sleep time between rendering consecutive frames)
collector.collect(n_episode=1, render=0.03)
# sample data with a given number of batch-size:
batch_data = collector.sample(batch_size=64)
# policy.learn(batch_data) # btw, vanilla policy gradient only
# supports on-policy training, so here we pick all data in the buffer
batch_data = collector.sample(batch_size=0)
policy.learn(batch_data)
# on-policy algorithms use the collected data only once, so here we
# clear the buffer
collector.reset_buffer()
For the scenario of collecting data from multiple environments to a single
buffer, the cache buffers will turn on automatically. It may return the
data more than the given limitation.
.. note::
Please make sure the given environment has a time limitation.
"""
def __init__(self, policy, env, buffer=None, stat_size=100,
store_obs_next=True, **kwargs):
super().__init__()
self.env = env
self.env_num = 1
self.collect_step = 0
self.collect_episode = 0
self.collect_time = 0
if buffer is None:
self.buffer = ReplayBuffer(100)
else:
self.buffer = buffer
self.policy = policy
self.process_fn = policy.process_fn
self._multi_env = isinstance(env, BaseVectorEnv)
self._multi_buf = False # True if buf is a list
# need multiple cache buffers only if storing in one buffer
self._cached_buf = []
if self._multi_env:
self.env_num = len(env)
if isinstance(self.buffer, list):
assert len(self.buffer) == self.env_num, \
'The number of data buffer does not match the number of ' \
'input env.'
self._multi_buf = True
elif isinstance(self.buffer, ReplayBuffer):
self._cached_buf = [
ListReplayBuffer() for _ in range(self.env_num)]
else:
raise TypeError('The buffer in data collector is invalid!')
self.reset_env()
self.reset_buffer()
# state over batch is either a list, an np.ndarray, or a torch.Tensor
self.state = None
self.step_speed = MovAvg(stat_size)
self.episode_speed = MovAvg(stat_size)
self._save_s_ = store_obs_next
[docs] def reset_buffer(self):
"""Reset the main data buffer."""
if self._multi_buf:
for b in self.buffer:
b.reset()
else:
self.buffer.reset()
[docs] def get_env_num(self):
"""Return the number of environments the collector has."""
return self.env_num
[docs] def reset_env(self):
"""Reset all of the environment(s)' states and reset all of the cache
buffers (if need).
"""
self._obs = self.env.reset()
self._act = self._rew = self._done = self._info = None
if self._multi_env:
self.reward = np.zeros(self.env_num)
self.length = np.zeros(self.env_num)
else:
self.reward, self.length = 0, 0
for b in self._cached_buf:
b.reset()
[docs] def seed(self, seed=None):
"""Reset all the seed(s) of the given environment(s)."""
if hasattr(self.env, 'seed'):
return self.env.seed(seed)
[docs] def render(self, **kwargs):
"""Render all the environment(s)."""
if hasattr(self.env, 'render'):
return self.env.render(**kwargs)
[docs] def close(self):
"""Close the environment(s)."""
if hasattr(self.env, 'close'):
self.env.close()
def _make_batch(self, data):
if isinstance(data, np.ndarray):
return data[None]
else:
return np.array([data])
[docs] def collect(self, n_step=0, n_episode=0, render=0):
"""Collect a specified number of step or episode.
:param int n_step: how many steps you want to collect.
:param n_episode: how many episodes you want to collect (in each
environment).
:type n_episode: int or list
:param float render: the sleep time between rendering consecutive
frames. No rendering if it is ``0`` (default option).
.. note::
One and only one collection number specification is permitted,
either ``n_step`` or ``n_episode``.
:return: A dict including the following keys
* ``n/ep`` the collected number of episodes.
* ``n/st`` the collected number of steps.
* ``v/st`` the speed of steps per second.
* ``v/ep`` the speed of episode per second.
* ``rew`` the mean reward over collected episodes.
* ``len`` the mean length over collected episodes.
"""
warning_count = 0
if not self._multi_env:
n_episode = np.sum(n_episode)
start_time = time.time()
assert sum([(n_step != 0), (n_episode != 0)]) == 1, \
"One and only one collection number specification is permitted!"
cur_step = 0
cur_episode = np.zeros(self.env_num) if self._multi_env else 0
reward_sum = 0
length_sum = 0
while True:
if warning_count >= 100000:
warnings.warn(
'There are already many steps in an episode. '
'You should add a time limitation to your environment!',
Warning)
if self._multi_env:
batch_data = Batch(
obs=self._obs, act=self._act, rew=self._rew,
done=self._done, obs_next=None, info=self._info)
else:
batch_data = Batch(
obs=self._make_batch(self._obs),
act=self._make_batch(self._act),
rew=self._make_batch(self._rew),
done=self._make_batch(self._done),
obs_next=None,
info=self._make_batch(self._info))
with torch.no_grad():
result = self.policy(batch_data, self.state)
self.state = result.state if hasattr(result, 'state') else None
if isinstance(result.act, torch.Tensor):
self._act = result.act.detach().cpu().numpy()
elif not isinstance(self._act, np.ndarray):
self._act = np.array(result.act)
else:
self._act = result.act
obs_next, self._rew, self._done, self._info = self.env.step(
self._act if self._multi_env else self._act[0])
if render > 0:
self.env.render()
time.sleep(render)
self.length += 1
self.reward += self._rew
if self._multi_env:
for i in range(self.env_num):
data = {
'obs': self._obs[i], 'act': self._act[i],
'rew': self._rew[i], 'done': self._done[i],
'obs_next': obs_next[i] if self._save_s_ else None,
'info': self._info[i]}
if self._cached_buf:
warning_count += 1
self._cached_buf[i].add(**data)
elif self._multi_buf:
warning_count += 1
self.buffer[i].add(**data)
cur_step += 1
else:
warning_count += 1
self.buffer.add(**data)
cur_step += 1
if self._done[i]:
if n_step != 0 or np.isscalar(n_episode) or \
cur_episode[i] < n_episode[i]:
cur_episode[i] += 1
reward_sum += self.reward[i]
length_sum += self.length[i]
if self._cached_buf:
cur_step += len(self._cached_buf[i])
self.buffer.update(self._cached_buf[i])
self.reward[i], self.length[i] = 0, 0
if self._cached_buf:
self._cached_buf[i].reset()
if isinstance(self.state, list):
self.state[i] = None
elif self.state is not None:
if isinstance(self.state[i], dict):
self.state[i] = {}
else:
self.state[i] = self.state[i] * 0
if isinstance(self.state, torch.Tensor):
# remove ref count in pytorch (?)
self.state = self.state.detach()
if sum(self._done):
obs_next = self.env.reset(np.where(self._done)[0])
if n_episode != 0:
if isinstance(n_episode, list) and \
(cur_episode >= np.array(n_episode)).all() or \
np.isscalar(n_episode) and \
cur_episode.sum() >= n_episode:
break
else:
self.buffer.add(
self._obs, self._act[0], self._rew,
self._done, obs_next if self._save_s_ else None,
self._info)
cur_step += 1
if self._done:
cur_episode += 1
reward_sum += self.reward
length_sum += self.length
self.reward, self.length = 0, 0
self.state = None
obs_next = self.env.reset()
if n_episode != 0 and cur_episode >= n_episode:
break
if n_step != 0 and cur_step >= n_step:
break
self._obs = obs_next
self._obs = obs_next
if self._multi_env:
cur_episode = sum(cur_episode)
duration = time.time() - start_time
self.step_speed.add(cur_step / duration)
self.episode_speed.add(cur_episode / duration)
self.collect_step += cur_step
self.collect_episode += cur_episode
self.collect_time += duration
if isinstance(n_episode, list):
n_episode = np.sum(n_episode)
else:
n_episode = max(cur_episode, 1)
return {
'n/ep': cur_episode,
'n/st': cur_step,
'v/st': self.step_speed.get(),
'v/ep': self.episode_speed.get(),
'rew': reward_sum / n_episode,
'len': length_sum / n_episode,
}
[docs] def sample(self, batch_size):
"""Sample a data batch from the internal replay buffer. It will call
:meth:`~tianshou.policy.BasePolicy.process_fn` before returning
the final batch data.
:param int batch_size: ``0`` means it will extract all the data from
the buffer, otherwise it will extract the data with the given
batch_size.
"""
if self._multi_buf:
if batch_size > 0:
lens = [len(b) for b in self.buffer]
total = sum(lens)
batch_index = np.random.choice(
total, batch_size, p=np.array(lens) / total)
else:
batch_index = np.array([])
batch_data = Batch()
for i, b in enumerate(self.buffer):
cur_batch = (batch_index == i).sum()
if batch_size and cur_batch or batch_size <= 0:
batch, indice = b.sample(cur_batch)
batch = self.process_fn(batch, b, indice)
batch_data.append(batch)
else:
batch_data, indice = self.buffer.sample(batch_size)
batch_data = self.process_fn(batch_data, self.buffer, indice)
return batch_data