import time
import tqdm
from torch.utils.tensorboard import SummaryWriter
from typing import Dict, List, Union, Callable, Optional
from tianshou.data import Collector
from tianshou.policy import BasePolicy
from tianshou.utils import tqdm_config, MovAvg
from tianshou.trainer import test_episode, gather_info
[docs]def offpolicy_trainer(
policy: BasePolicy,
train_collector: Collector,
test_collector: Collector,
max_epoch: int,
step_per_epoch: int,
collect_per_step: int,
episode_per_test: Union[int, List[int]],
batch_size: int,
update_per_step: int = 1,
train_fn: Optional[Callable[[int], None]] = None,
test_fn: Optional[Callable[[int], None]] = None,
stop_fn: Optional[Callable[[float], bool]] = None,
save_fn: Optional[Callable[[BasePolicy], None]] = None,
log_fn: Optional[Callable[[dict], None]] = None,
writer: Optional[SummaryWriter] = None,
log_interval: int = 1,
verbose: bool = True,
**kwargs
) -> Dict[str, Union[float, str]]:
"""A wrapper for off-policy trainer procedure.
:param policy: an instance of the :class:`~tianshou.policy.BasePolicy`
class.
:param train_collector: the collector used for training.
:type train_collector: :class:`~tianshou.data.Collector`
:param test_collector: the collector used for testing.
:type test_collector: :class:`~tianshou.data.Collector`
:param int max_epoch: the maximum of epochs for training. The training
process might be finished before reaching the ``max_epoch``.
:param int step_per_epoch: the number of step for updating policy network
in one epoch.
:param int collect_per_step: the number of frames the collector would
collect before the network update. In other words, collect some frames
and do some policy network update.
:param episode_per_test: the number of episodes for one policy evaluation.
:param int batch_size: the batch size of sample data, which is going to
feed in the policy network.
:param int update_per_step: the number of times the policy network would
be updated after frames be collected. In other words, collect some
frames and do some policy network update.
:param function train_fn: a function receives the current number of epoch
index and performs some operations at the beginning of training in this
epoch.
:param function test_fn: a function receives the current number of epoch
index and performs some operations at the beginning of testing in this
epoch.
:param function save_fn: a function for saving policy when the undiscounted
average mean reward in evaluation phase gets better.
:param function stop_fn: a function receives the average undiscounted
returns of the testing result, return a boolean which indicates whether
reaching the goal.
:param function log_fn: a function receives env info for logging.
:param torch.utils.tensorboard.SummaryWriter writer: a TensorBoard
SummaryWriter.
:param int log_interval: the log interval of the writer.
:param bool verbose: whether to print the information.
:return: See :func:`~tianshou.trainer.gather_info`.
"""
global_step = 0
best_epoch, best_reward = -1, -1
stat = {}
start_time = time.time()
test_in_train = train_collector.policy == policy
for epoch in range(1, 1 + max_epoch):
# train
policy.train()
if train_fn:
train_fn(epoch)
with tqdm.tqdm(total=step_per_epoch, desc=f'Epoch #{epoch}',
**tqdm_config) as t:
while t.n < t.total:
result = train_collector.collect(n_step=collect_per_step,
log_fn=log_fn)
data = {}
if test_in_train and stop_fn and stop_fn(result['rew']):
test_result = test_episode(
policy, test_collector, test_fn,
epoch, episode_per_test)
if stop_fn and stop_fn(test_result['rew']):
if save_fn:
save_fn(policy)
for k in result.keys():
data[k] = f'{result[k]:.2f}'
t.set_postfix(**data)
return gather_info(
start_time, train_collector, test_collector,
test_result['rew'])
else:
policy.train()
if train_fn:
train_fn(epoch)
for i in range(update_per_step * min(
result['n/st'] // collect_per_step, t.total - t.n)):
global_step += 1
losses = policy.learn(train_collector.sample(batch_size))
for k in result.keys():
data[k] = f'{result[k]:.2f}'
if writer and global_step % log_interval == 0:
writer.add_scalar(
k, result[k], global_step=global_step)
for k in losses.keys():
if stat.get(k) is None:
stat[k] = MovAvg()
stat[k].add(losses[k])
data[k] = f'{stat[k].get():.6f}'
if writer and global_step % log_interval == 0:
writer.add_scalar(
k, stat[k].get(), global_step=global_step)
t.update(1)
t.set_postfix(**data)
if t.n <= t.total:
t.update()
# test
result = test_episode(
policy, test_collector, test_fn, epoch, episode_per_test)
if best_epoch == -1 or best_reward < result['rew']:
best_reward = result['rew']
best_epoch = epoch
if save_fn:
save_fn(policy)
if verbose:
print(f'Epoch #{epoch}: test_reward: {result["rew"]:.6f}, '
f'best_reward: {best_reward:.6f} in #{best_epoch}')
if stop_fn and stop_fn(best_reward):
break
return gather_info(
start_time, train_collector, test_collector, best_reward)