522f7fbf98
This PR adds strict typing to the output of `update` and `learn` in all
policies. This will likely be the last large refactoring PR before the
next release (0.6.0, not 1.0.0), so it requires some attention. Several
difficulties were encountered on the path to that goal:
1. The policy hierarchy is actually "broken" in the sense that the keys
of dicts that were output by `learn` did not follow the same enhancement
(inheritance) pattern as the policies. This is a real problem and should
be addressed in the near future. Generally, several aspects of the
policy design and hierarchy might deserve a dedicated discussion.
2. Each policy needs to be generic in the stats return type, because one
might want to extend it at some point and then also extend the stats.
Even within the source code base this pattern is necessary in many
places.
3. The interaction between learn and update is a bit quirky, we
currently handle it by having update modify special field inside
TrainingStats, whereas all other fields are handled by learn.
4. The IQM module is a policy wrapper and required a
TrainingStatsWrapper. The latter relies on a bunch of black magic.
They were addressed by:
1. Live with the broken hierarchy, which is now made visible by bounds
in generics. We use type: ignore where appropriate.
2. Make all policies generic with bounds following the policy
inheritance hierarchy (which is incorrect, see above). We experimented a
bit with nested TrainingStats classes, but that seemed to add more
complexity and be harder to understand. Unfortunately, mypy thinks that
the code below is wrong, wherefore we have to add `type: ignore` to the
return of each `learn`
```python
T = TypeVar("T", bound=int)
def f() -> T:
return 3
```
3. See above
4. Write representative tests for the `TrainingStatsWrapper`. Still, the
black magic might cause nasty surprises down the line (I am not proud of
it)...
Closes #933
---------
Co-authored-by: Maximilian Huettenrauch <m.huettenrauch@appliedai.de>
Co-authored-by: Michael Panchenko <m.panchenko@appliedai.de>
189 lines
7.1 KiB
Python
189 lines
7.1 KiB
Python
import argparse
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import os
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import pprint
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import gymnasium as gym
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import numpy as np
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import pytest
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import torch
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from gymnasium.spaces import Box
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from torch.utils.tensorboard import SummaryWriter
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from tianshou.data import Collector, VectorReplayBuffer
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from tianshou.policy import A2CPolicy, ImitationPolicy
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from tianshou.trainer import OffpolicyTrainer, OnpolicyTrainer
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from tianshou.utils import TensorboardLogger
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from tianshou.utils.net.common import ActorCritic, Net
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from tianshou.utils.net.discrete import Actor, Critic
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try:
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import envpool
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except ImportError:
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envpool = None
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def get_args():
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parser = argparse.ArgumentParser()
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parser.add_argument("--task", type=str, default="CartPole-v0")
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parser.add_argument("--reward-threshold", type=float, default=None)
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parser.add_argument("--seed", type=int, default=1)
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parser.add_argument("--buffer-size", type=int, default=20000)
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parser.add_argument("--lr", type=float, default=1e-3)
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parser.add_argument("--il-lr", type=float, default=1e-3)
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parser.add_argument("--gamma", type=float, default=0.9)
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parser.add_argument("--epoch", type=int, default=10)
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parser.add_argument("--step-per-epoch", type=int, default=50000)
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parser.add_argument("--il-step-per-epoch", type=int, default=1000)
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parser.add_argument("--episode-per-collect", type=int, default=16)
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parser.add_argument("--step-per-collect", type=int, default=16)
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parser.add_argument("--update-per-step", type=float, default=1 / 16)
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parser.add_argument("--repeat-per-collect", type=int, default=1)
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parser.add_argument("--batch-size", type=int, default=64)
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parser.add_argument("--hidden-sizes", type=int, nargs="*", default=[64, 64])
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parser.add_argument("--imitation-hidden-sizes", type=int, nargs="*", default=[128])
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parser.add_argument("--training-num", type=int, default=16)
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parser.add_argument("--test-num", type=int, default=100)
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parser.add_argument("--logdir", type=str, default="log")
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parser.add_argument("--render", type=float, default=0.0)
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parser.add_argument(
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"--device",
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type=str,
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default="cuda" if torch.cuda.is_available() else "cpu",
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)
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# a2c special
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parser.add_argument("--vf-coef", type=float, default=0.5)
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parser.add_argument("--ent-coef", type=float, default=0.0)
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parser.add_argument("--max-grad-norm", type=float, default=None)
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parser.add_argument("--gae-lambda", type=float, default=1.0)
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parser.add_argument("--rew-norm", action="store_true", default=False)
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return parser.parse_known_args()[0]
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@pytest.mark.skipif(envpool is None, reason="EnvPool doesn't support this platform")
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def test_a2c_with_il(args=get_args()):
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# if you want to use python vector env, please refer to other test scripts
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train_envs = env = envpool.make(
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args.task,
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env_type="gymnasium",
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num_envs=args.training_num,
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seed=args.seed,
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)
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test_envs = envpool.make(
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args.task,
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env_type="gymnasium",
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num_envs=args.test_num,
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seed=args.seed,
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)
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args.state_shape = env.observation_space.shape or env.observation_space.n
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args.action_shape = env.action_space.shape or env.action_space.n
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if args.reward_threshold is None:
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default_reward_threshold = {"CartPole-v0": 195}
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args.reward_threshold = default_reward_threshold.get(args.task, env.spec.reward_threshold)
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# seed
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np.random.seed(args.seed)
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torch.manual_seed(args.seed)
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# model
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net = Net(args.state_shape, hidden_sizes=args.hidden_sizes, device=args.device)
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actor = Actor(net, args.action_shape, device=args.device).to(args.device)
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critic = Critic(net, device=args.device).to(args.device)
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optim = torch.optim.Adam(ActorCritic(actor, critic).parameters(), lr=args.lr)
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dist = torch.distributions.Categorical
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policy = A2CPolicy(
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actor=actor,
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critic=critic,
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optim=optim,
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dist_fn=dist,
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action_scaling=isinstance(env.action_space, Box),
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discount_factor=args.gamma,
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gae_lambda=args.gae_lambda,
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vf_coef=args.vf_coef,
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ent_coef=args.ent_coef,
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max_grad_norm=args.max_grad_norm,
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reward_normalization=args.rew_norm,
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action_space=env.action_space,
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)
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# collector
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train_collector = Collector(
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policy,
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train_envs,
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VectorReplayBuffer(args.buffer_size, len(train_envs)),
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)
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test_collector = Collector(policy, test_envs)
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# log
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log_path = os.path.join(args.logdir, args.task, "a2c")
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writer = SummaryWriter(log_path)
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logger = TensorboardLogger(writer)
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def save_best_fn(policy):
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torch.save(policy.state_dict(), os.path.join(log_path, "policy.pth"))
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def stop_fn(mean_rewards):
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return mean_rewards >= args.reward_threshold
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# trainer
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result = OnpolicyTrainer(
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policy=policy,
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train_collector=train_collector,
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test_collector=test_collector,
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max_epoch=args.epoch,
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step_per_epoch=args.step_per_epoch,
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repeat_per_collect=args.repeat_per_collect,
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episode_per_test=args.test_num,
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batch_size=args.batch_size,
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episode_per_collect=args.episode_per_collect,
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stop_fn=stop_fn,
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save_best_fn=save_best_fn,
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logger=logger,
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).run()
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assert stop_fn(result.best_reward)
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if __name__ == "__main__":
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pprint.pprint(result)
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# Let's watch its performance!
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env = gym.make(args.task)
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policy.eval()
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collector = Collector(policy, env)
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result = collector.collect(n_episode=1, render=args.render)
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print(f"Final reward: {result.returns_stat.mean}, length: {result.lens_stat.mean}")
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policy.eval()
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# here we define an imitation collector with a trivial policy
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# if args.task == 'CartPole-v0':
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# env.spec.reward_threshold = 190 # lower the goal
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net = Net(args.state_shape, hidden_sizes=args.hidden_sizes, device=args.device)
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net = Actor(net, args.action_shape, device=args.device).to(args.device)
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optim = torch.optim.Adam(net.parameters(), lr=args.il_lr)
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il_policy = ImitationPolicy(actor=net, optim=optim, action_space=env.action_space)
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il_test_collector = Collector(
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il_policy,
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envpool.make(args.task, env_type="gymnasium", num_envs=args.test_num, seed=args.seed),
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)
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train_collector.reset()
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result = OffpolicyTrainer(
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policy=il_policy,
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train_collector=train_collector,
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test_collector=il_test_collector,
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max_epoch=args.epoch,
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step_per_epoch=args.il_step_per_epoch,
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step_per_collect=args.step_per_collect,
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episode_per_test=args.test_num,
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batch_size=args.batch_size,
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stop_fn=stop_fn,
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save_best_fn=save_best_fn,
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logger=logger,
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).run()
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assert stop_fn(result.best_reward)
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if __name__ == "__main__":
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pprint.pprint(result)
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# Let's watch its performance!
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env = gym.make(args.task)
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il_policy.eval()
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collector = Collector(il_policy, env)
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result = collector.collect(n_episode=1, render=args.render)
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print(f"Final reward: {result.returns_stat.mean}, length: {result.lens_stat.mean}")
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if __name__ == "__main__":
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test_a2c_with_il()
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