import time
import warnings
from typing import Any, Callable, Dict, List, Optional, Union
import gym
import numpy as np
import torch
from tianshou.data import (
Batch,
CachedReplayBuffer,
ReplayBuffer,
ReplayBufferManager,
VectorReplayBuffer,
to_numpy,
)
from tianshou.data.batch import _alloc_by_keys_diff
from tianshou.env import BaseVectorEnv, DummyVectorEnv
from tianshou.policy import BasePolicy
[docs]class Collector(object):
"""Collector enables the policy to interact with different types of envs with \
exact number of steps or episodes.
:param policy: an instance of the :class:`~tianshou.policy.BasePolicy` class.
:param env: a ``gym.Env`` environment or an instance of the
:class:`~tianshou.env.BaseVectorEnv` class.
:param buffer: an instance of the :class:`~tianshou.data.ReplayBuffer` class.
If set to None, it will not store the data. Default to None.
:param function preprocess_fn: a function called before the data has been added to
the buffer, see issue #42 and :ref:`preprocess_fn`. Default to None.
:param bool exploration_noise: determine whether the action needs to be modified
with corresponding policy's exploration noise. If so, "policy.
exploration_noise(act, batch)" will be called automatically to add the
exploration noise into action. Default to False.
The "preprocess_fn" is a function called before the data has been added to the
buffer with batch format. It will receive only "obs" and "env_id" when the
collector resets the environment, and will receive six keys "obs_next", "rew",
"done", "info", "policy" and "env_id" in a normal env step. It returns either a
dict or a :class:`~tianshou.data.Batch` with the modified keys and values. Examples
are in "test/base/test_collector.py".
.. note::
Please make sure the given environment has a time limitation if using n_episode
collect option.
"""
def __init__(
self,
policy: BasePolicy,
env: Union[gym.Env, BaseVectorEnv],
buffer: Optional[ReplayBuffer] = None,
preprocess_fn: Optional[Callable[..., Batch]] = None,
exploration_noise: bool = False,
) -> None:
super().__init__()
if isinstance(env, gym.Env) and not hasattr(env, "__len__"):
warnings.warn("Single environment detected, wrap to DummyVectorEnv.")
env = DummyVectorEnv([lambda: env])
self.env = env
self.env_num = len(env)
self.exploration_noise = exploration_noise
self._assign_buffer(buffer)
self.policy = policy
self.preprocess_fn = preprocess_fn
self._action_space = env.action_space
# avoid creating attribute outside __init__
self.reset()
def _assign_buffer(self, buffer: Optional[ReplayBuffer]) -> None:
"""Check if the buffer matches the constraint."""
if buffer is None:
buffer = VectorReplayBuffer(self.env_num, self.env_num)
elif isinstance(buffer, ReplayBufferManager):
assert buffer.buffer_num >= self.env_num
if isinstance(buffer, CachedReplayBuffer):
assert buffer.cached_buffer_num >= self.env_num
else: # ReplayBuffer or PrioritizedReplayBuffer
assert buffer.maxsize > 0
if self.env_num > 1:
if type(buffer) == ReplayBuffer:
buffer_type = "ReplayBuffer"
vector_type = "VectorReplayBuffer"
else:
buffer_type = "PrioritizedReplayBuffer"
vector_type = "PrioritizedVectorReplayBuffer"
raise TypeError(
f"Cannot use {buffer_type}(size={buffer.maxsize}, ...) to collect "
f"{self.env_num} envs,\n\tplease use {vector_type}(total_size="
f"{buffer.maxsize}, buffer_num={self.env_num}, ...) instead."
)
self.buffer = buffer
[docs] def reset(self) -> None:
"""Reset all related variables in the collector."""
# use empty Batch for "state" so that self.data supports slicing
# convert empty Batch to None when passing data to policy
self.data = Batch(
obs={}, act={}, rew={}, done={}, obs_next={}, info={}, policy={}
)
self.reset_env()
self.reset_buffer()
self.reset_stat()
[docs] def reset_stat(self) -> None:
"""Reset the statistic variables."""
self.collect_step, self.collect_episode, self.collect_time = 0, 0, 0.0
[docs] def reset_buffer(self, keep_statistics: bool = False) -> None:
"""Reset the data buffer."""
self.buffer.reset(keep_statistics=keep_statistics)
[docs] def reset_env(self) -> None:
"""Reset all of the environments."""
obs = self.env.reset()
if self.preprocess_fn:
obs = self.preprocess_fn(obs=obs,
env_id=np.arange(self.env_num)).get("obs", obs)
self.data.obs = obs
def _reset_state(self, id: Union[int, List[int]]) -> None:
"""Reset the hidden state: self.data.state[id]."""
if hasattr(self.data.policy, "hidden_state"):
state = self.data.policy.hidden_state # it is a reference
if isinstance(state, torch.Tensor):
state[id].zero_()
elif isinstance(state, np.ndarray):
state[id] = None if state.dtype == object else 0
elif isinstance(state, Batch):
state.empty_(id)
[docs] def collect(
self,
n_step: Optional[int] = None,
n_episode: Optional[int] = None,
random: bool = False,
render: Optional[float] = None,
no_grad: bool = True,
) -> Dict[str, Any]:
"""Collect a specified number of step or episode.
To ensure unbiased sampling result with n_episode option, this function will
first collect ``n_episode - env_num`` episodes, then for the last ``env_num``
episodes, they will be collected evenly from each env.
:param int n_step: how many steps you want to collect.
:param int n_episode: how many episodes you want to collect.
:param bool random: whether to use random policy for collecting data. Default
to False.
:param float render: the sleep time between rendering consecutive frames.
Default to None (no rendering).
:param bool no_grad: whether to retain gradient in policy.forward(). Default to
True (no gradient retaining).
.. 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`` collected number of episodes.
* ``n/st`` collected number of steps.
* ``rews`` array of episode reward over collected episodes.
* ``lens`` array of episode length over collected episodes.
* ``idxs`` array of episode start index in buffer over collected episodes.
"""
assert not self.env.is_async, "Please use AsyncCollector if using async venv."
if n_step is not None:
assert n_episode is None, (
f"Only one of n_step or n_episode is allowed in Collector."
f"collect, got n_step={n_step}, n_episode={n_episode}."
)
assert n_step > 0
if not n_step % self.env_num == 0:
warnings.warn(
f"n_step={n_step} is not a multiple of #env ({self.env_num}), "
"which may cause extra transitions collected into the buffer."
)
ready_env_ids = np.arange(self.env_num)
elif n_episode is not None:
assert n_episode > 0
ready_env_ids = np.arange(min(self.env_num, n_episode))
self.data = self.data[:min(self.env_num, n_episode)]
else:
raise TypeError(
"Please specify at least one (either n_step or n_episode) "
"in AsyncCollector.collect()."
)
start_time = time.time()
step_count = 0
episode_count = 0
episode_rews = []
episode_lens = []
episode_start_indices = []
while True:
assert len(self.data) == len(ready_env_ids)
# restore the state: if the last state is None, it won't store
last_state = self.data.policy.pop("hidden_state", None)
# get the next action
if random:
self.data.update(
act=[self._action_space[i].sample() for i in ready_env_ids]
)
else:
if no_grad:
with torch.no_grad(): # faster than retain_grad version
# self.data.obs will be used by agent to get result
result = self.policy(self.data, last_state)
else:
result = self.policy(self.data, last_state)
# update state / act / policy into self.data
policy = result.get("policy", Batch())
assert isinstance(policy, Batch)
state = result.get("state", None)
if state is not None:
policy.hidden_state = state # save state into buffer
act = to_numpy(result.act)
if self.exploration_noise:
act = self.policy.exploration_noise(act, self.data)
self.data.update(policy=policy, act=act)
# get bounded and remapped actions first (not saved into buffer)
action_remap = self.policy.map_action(self.data.act)
# step in env
result = self.env.step(action_remap, ready_env_ids) # type: ignore
obs_next, rew, done, info = result
self.data.update(obs_next=obs_next, rew=rew, done=done, info=info)
if self.preprocess_fn:
self.data.update(
self.preprocess_fn(
obs_next=self.data.obs_next,
rew=self.data.rew,
done=self.data.done,
info=self.data.info,
policy=self.data.policy,
env_id=ready_env_ids,
)
)
if render:
self.env.render()
if render > 0 and not np.isclose(render, 0):
time.sleep(render)
# add data into the buffer
ptr, ep_rew, ep_len, ep_idx = self.buffer.add(
self.data, buffer_ids=ready_env_ids
)
# collect statistics
step_count += len(ready_env_ids)
if np.any(done):
env_ind_local = np.where(done)[0]
env_ind_global = ready_env_ids[env_ind_local]
episode_count += len(env_ind_local)
episode_lens.append(ep_len[env_ind_local])
episode_rews.append(ep_rew[env_ind_local])
episode_start_indices.append(ep_idx[env_ind_local])
# now we copy obs_next to obs, but since there might be
# finished episodes, we have to reset finished envs first.
obs_reset = self.env.reset(env_ind_global)
if self.preprocess_fn:
obs_reset = self.preprocess_fn(
obs=obs_reset, env_id=env_ind_global
).get("obs", obs_reset)
self.data.obs_next[env_ind_local] = obs_reset
for i in env_ind_local:
self._reset_state(i)
# remove surplus env id from ready_env_ids
# to avoid bias in selecting environments
if n_episode:
surplus_env_num = len(ready_env_ids) - (n_episode - episode_count)
if surplus_env_num > 0:
mask = np.ones_like(ready_env_ids, dtype=bool)
mask[env_ind_local[:surplus_env_num]] = False
ready_env_ids = ready_env_ids[mask]
self.data = self.data[mask]
self.data.obs = self.data.obs_next
if (n_step and step_count >= n_step) or \
(n_episode and episode_count >= n_episode):
break
# generate statistics
self.collect_step += step_count
self.collect_episode += episode_count
self.collect_time += max(time.time() - start_time, 1e-9)
if n_episode:
self.data = Batch(
obs={}, act={}, rew={}, done={}, obs_next={}, info={}, policy={}
)
self.reset_env()
if episode_count > 0:
rews, lens, idxs = list(
map(
np.concatenate,
[episode_rews, episode_lens, episode_start_indices]
)
)
else:
rews, lens, idxs = np.array([]), np.array([], int), np.array([], int)
return {
"n/ep": episode_count,
"n/st": step_count,
"rews": rews,
"lens": lens,
"idxs": idxs,
}
[docs]class AsyncCollector(Collector):
"""Async Collector handles async vector environment.
The arguments are exactly the same as :class:`~tianshou.data.Collector`, please
refer to :class:`~tianshou.data.Collector` for more detailed explanation.
"""
def __init__(
self,
policy: BasePolicy,
env: BaseVectorEnv,
buffer: Optional[ReplayBuffer] = None,
preprocess_fn: Optional[Callable[..., Batch]] = None,
exploration_noise: bool = False,
) -> None:
assert env.is_async
super().__init__(policy, env, buffer, preprocess_fn, exploration_noise)
[docs] def reset_env(self) -> None:
super().reset_env()
self._ready_env_ids = np.arange(self.env_num)
[docs] def collect(
self,
n_step: Optional[int] = None,
n_episode: Optional[int] = None,
random: bool = False,
render: Optional[float] = None,
no_grad: bool = True,
) -> Dict[str, Any]:
"""Collect a specified number of step or episode with async env setting.
This function doesn't collect exactly n_step or n_episode number of
transitions. Instead, in order to support async setting, it may collect more
than given n_step or n_episode transitions and save into buffer.
:param int n_step: how many steps you want to collect.
:param int n_episode: how many episodes you want to collect.
:param bool random: whether to use random policy for collecting data. Default
to False.
:param float render: the sleep time between rendering consecutive frames.
Default to None (no rendering).
:param bool no_grad: whether to retain gradient in policy.forward(). Default to
True (no gradient retaining).
.. 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`` collected number of episodes.
* ``n/st`` collected number of steps.
* ``rews`` array of episode reward over collected episodes.
* ``lens`` array of episode length over collected episodes.
* ``idxs`` array of episode start index in buffer over collected episodes.
"""
# collect at least n_step or n_episode
if n_step is not None:
assert n_episode is None, (
"Only one of n_step or n_episode is allowed in Collector."
f"collect, got n_step={n_step}, n_episode={n_episode}."
)
assert n_step > 0
elif n_episode is not None:
assert n_episode > 0
else:
raise TypeError(
"Please specify at least one (either n_step or n_episode) "
"in AsyncCollector.collect()."
)
warnings.warn("Using async setting may collect extra transitions into buffer.")
ready_env_ids = self._ready_env_ids
start_time = time.time()
step_count = 0
episode_count = 0
episode_rews = []
episode_lens = []
episode_start_indices = []
while True:
whole_data = self.data
self.data = self.data[ready_env_ids]
assert len(whole_data) == self.env_num # major difference
# restore the state: if the last state is None, it won't store
last_state = self.data.policy.pop("hidden_state", None)
# get the next action
if random:
self.data.update(
act=[self._action_space[i].sample() for i in ready_env_ids]
)
else:
if no_grad:
with torch.no_grad(): # faster than retain_grad version
# self.data.obs will be used by agent to get result
result = self.policy(self.data, last_state)
else:
result = self.policy(self.data, last_state)
# update state / act / policy into self.data
policy = result.get("policy", Batch())
assert isinstance(policy, Batch)
state = result.get("state", None)
if state is not None:
policy.hidden_state = state # save state into buffer
act = to_numpy(result.act)
if self.exploration_noise:
act = self.policy.exploration_noise(act, self.data)
self.data.update(policy=policy, act=act)
# save act/policy before env.step
try:
whole_data.act[ready_env_ids] = self.data.act
whole_data.policy[ready_env_ids] = self.data.policy
except ValueError:
_alloc_by_keys_diff(whole_data, self.data, self.env_num, False)
whole_data[ready_env_ids] = self.data # lots of overhead
# get bounded and remapped actions first (not saved into buffer)
action_remap = self.policy.map_action(self.data.act)
# step in env
result = self.env.step(action_remap, ready_env_ids) # type: ignore
obs_next, rew, done, info = result
# change self.data here because ready_env_ids has changed
ready_env_ids = np.array([i["env_id"] for i in info])
self.data = whole_data[ready_env_ids]
self.data.update(obs_next=obs_next, rew=rew, done=done, info=info)
if self.preprocess_fn:
self.data.update(
self.preprocess_fn(
obs_next=self.data.obs_next,
rew=self.data.rew,
done=self.data.done,
info=self.data.info,
env_id=ready_env_ids,
)
)
if render:
self.env.render()
if render > 0 and not np.isclose(render, 0):
time.sleep(render)
# add data into the buffer
ptr, ep_rew, ep_len, ep_idx = self.buffer.add(
self.data, buffer_ids=ready_env_ids
)
# collect statistics
step_count += len(ready_env_ids)
if np.any(done):
env_ind_local = np.where(done)[0]
env_ind_global = ready_env_ids[env_ind_local]
episode_count += len(env_ind_local)
episode_lens.append(ep_len[env_ind_local])
episode_rews.append(ep_rew[env_ind_local])
episode_start_indices.append(ep_idx[env_ind_local])
# now we copy obs_next to obs, but since there might be
# finished episodes, we have to reset finished envs first.
obs_reset = self.env.reset(env_ind_global)
if self.preprocess_fn:
obs_reset = self.preprocess_fn(
obs=obs_reset, env_id=env_ind_global
).get("obs", obs_reset)
self.data.obs_next[env_ind_local] = obs_reset
for i in env_ind_local:
self._reset_state(i)
try:
whole_data.obs[ready_env_ids] = self.data.obs_next
whole_data.rew[ready_env_ids] = self.data.rew
whole_data.done[ready_env_ids] = self.data.done
whole_data.info[ready_env_ids] = self.data.info
except ValueError:
_alloc_by_keys_diff(whole_data, self.data, self.env_num, False)
self.data.obs = self.data.obs_next
whole_data[ready_env_ids] = self.data # lots of overhead
self.data = whole_data
if (n_step and step_count >= n_step) or \
(n_episode and episode_count >= n_episode):
break
self._ready_env_ids = ready_env_ids
# generate statistics
self.collect_step += step_count
self.collect_episode += episode_count
self.collect_time += max(time.time() - start_time, 1e-9)
if episode_count > 0:
rews, lens, idxs = list(
map(
np.concatenate,
[episode_rews, episode_lens, episode_start_indices]
)
)
else:
rews, lens, idxs = np.array([]), np.array([], int), np.array([], int)
return {
"n/ep": episode_count,
"n/st": step_count,
"rews": rews,
"lens": lens,
"idxs": idxs,
}