f1ece358d7
Due to the conservative approximation of the collision check, no option might be feasible, thus the necessity of a guaranteed fallback.
318 lines
12 KiB
Python
318 lines
12 KiB
Python
# %%
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from gail.discriminator import CnnDiscriminator
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from imitation.algorithms import adversarial
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import stable_baselines3
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import torch.utils.data
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import numpy as np
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from intersim.envs.intersimple import NRasterized
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import itertools
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from torch.distributions import Categorical
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import gym
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import torch
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import pickle
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import imitation.data.rollout as rollout
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import tempfile
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import pathlib
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from imitation.util import logger
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from stable_baselines3.common.env_util import make_vec_env
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model_name = 'gail_options_image'
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env_settings = {'agent': 51, 'width': 36, 'height': 36, 'm_per_px': 2}
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ALL_OPTIONS = [(v,t) for v in [0,2,4,6,8] for t in [5, 10, 20]] # option 0 is safe fallback
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class OptionsCnnPolicy(stable_baselines3.common.policies.ActorCriticCnnPolicy):
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def __init__(self, observation_space, *args, **kwargs):
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super().__init__(observation_space['obs'], *args, **kwargs)
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def _prior_distribution(self, s):
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latent_pi, latent_vf, latent_sde = self._get_latent(s)
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distribution = self._get_action_dist_from_latent(latent_pi, latent_sde)
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values = self.value_net(latent_vf)
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return values, distribution.distribution
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def predict(self, obs):
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s, m = obs['obs'], obs['mask']
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values, prior = self._prior_distribution(s)
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posterior = Categorical(prior.probs * m)
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ch = posterior.sample()
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return ch, values, posterior.log_prob(ch)
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def evaluate_actions(self, obs, ch):
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s, m = obs['obs'], obs['mask']
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values, prior = self._prior_distribution(s)
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posterior = Categorical(prior.probs * m)
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return values, posterior.log_prob(ch), posterior.entropy() # additional values used by PPO.train
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def available_actions(env):
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"""Return mask of available actions given current `env` state."""
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valid = np.array([feasible(env, generate_plan(env, i), i) for i in range(len(ALL_OPTIONS))])
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return valid
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def target_velocity_plan(current_v: float, target_v: float, t: int, dt: float):
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"""Smoothly target a velocity in a given number of steps"""
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# for now, constant acceleration
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a = (target_v - current_v) / (t * dt)
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return a*np.ones((t,))
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def generate_plan(env, i):
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"""Generate input profile for high-level action `i`."""
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assert i < len(ALL_OPTIONS), "Invalid option index {i}"
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target_v, t = ALL_OPTIONS[i]
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current_v = env._env.state[env._agent, 1].item() # extract from env
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plan = target_velocity_plan(current_v, target_v, t, env._env._dt)
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assert len(plan) == t, "incorrect plan length"
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return plan
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def check_future_collisions_fast(env, actions):
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"""Checks whether `env._agent` would collide with other agents assuming `actions` as input.
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Vehicles are (over-)approximated by single circles.
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Args:
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env (gym.Env): current environment state
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actions (list of torch.Tensor): list of B (T, nv, adims) T-length action profiles
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Returns:
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feasible (torch.Tensor): tensor of shape (B,) indicating whether the respective action profiles are collision-free
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"""
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B, (T, nv, _) = len(actions), actions[0].shape
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states = torch.stack(env._env.propagate_action_profile(actions), axis=0)
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assert states.shape == (B, T, nv, 5)
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distance = ((states[:, :, :, :2] - states[:, :, env._agent:env._agent+1, :2])**2).sum(-1).sqrt()
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distance = torch.where(distance.isnan(), np.inf*torch.ones_like(distance), distance) # only collide with spawned agents
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distance[:, :, env._agent] = np.inf # cannot collide with itself
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assert distance.shape == (B, T, nv)
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radius = (env._env._lengths**2 + env._env._widths**2).sqrt() / 2
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min_distance = radius[env._agent] + radius
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min_distance = min_distance.unsqueeze(0).unsqueeze(0)
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print('min_distance', min_distance.shape)
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assert min_distance.shape == (1, 1, nv)
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return (distance > min_distance).all(-1).all(-1)
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def feasible(env, plan, ch):
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"""Check if input profile is feasible given current `env` state. Action `ch=0` is safe fallback."""
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# zero pad plan - Take (T,) np plan and convert it to (T, nv, 1) torch.Tensor
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full_plan = torch.zeros(len(plan), env._env._nv, 1)
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full_plan[:, env._agent, 0] = torch.tensor(plan)
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valid = check_future_collisions_fast(env, [full_plan]) # check_future_collisions_fast takes in B-list and outputs (B,) bool tensor
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return ch == 0 or valid.item()
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def sample_ll(env, generator):
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"""Sample low-level (state, action) pairs for discriminator training."""
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done = True
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while True:
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if done:
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s = env.reset()
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done = False
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m = available_actions(env)
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ch, _, _ = generator.policy.predict({
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'obs': torch.tensor(s).unsqueeze(0).to(generator.policy.device),
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'mask': torch.tensor(m).unsqueeze(0).to(generator.policy.device),
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})
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plan = list(map(float, generate_plan(env, ch)))
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assert not done
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assert plan
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assert feasible(env, plan, ch), f'Infeasible hl action {ch}'
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while not done and plan and feasible(env, plan, ch):
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a, plan = env._normalize(plan[0]), plan[1:]
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nexts, _, done, _ = env.step(a)
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yield {
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'obs': s,
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'next_obs': nexts,
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'acts': np.array((a,)),
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'dones': np.array(done),
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}
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s = nexts
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def sample_hl(env, generator, discriminator):
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"""Sample high-level (state, action, reward) tuples for generator training."""
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done = True
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while True:
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episode_start = False
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if done:
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s = env.reset()
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m = available_actions(env)
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done = False
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episode_start = True
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obs = {'obs': s, 'mask': m}
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ch, value, log_prob = generator.policy.predict({
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'obs': torch.tensor(s).unsqueeze(0).to(generator.policy.device),
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'mask': torch.tensor(m).unsqueeze(0).to(generator.policy.device),
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})
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plan = list(map(float, generate_plan(env, ch)))
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r = 0
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steps = 0
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while not done and plan and feasible(env, plan, ch):
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a, plan = env._normalize(plan[0]), plan[1:]
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r += discriminator.discrim_net.discriminator(
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torch.tensor(s).unsqueeze(0).to(discriminator.discrim_net.device()),
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torch.tensor([[a]]).to(discriminator.discrim_net.device()),
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)
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steps += 1
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s, _, done, _ = env.step(a)
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m = available_actions(env)
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yield {
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'obs': obs,
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'action': ch,
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'reward': r.detach() / steps,
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'episode_start': episode_start,
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'value': value.detach(),
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'log_prob': log_prob.detach(),
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'done': done,
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}
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def flatten_transitions(transitions):
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return {
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'obs': np.stack(list(t['obs'] for t in transitions), axis=0),
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'next_obs': np.stack(list(t['next_obs'] for t in transitions), axis=0),
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'acts': np.stack(list(t['acts'] for t in transitions), axis=0),
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'dones': np.stack(list(t['dones'] for t in transitions), axis=0),
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}
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def train_discriminator(env, generator, discriminator, num_samples):
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transitions = list(itertools.islice(sample_ll(env, generator), num_samples))
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generator_samples = flatten_transitions(transitions)
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discriminator.train_disc(gen_samples=generator_samples)
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def train_generator(env, generator, discriminator, num_samples):
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generator_samples = list(itertools.islice(sample_hl(env, generator, discriminator), num_samples+1))
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generator.rollout_buffer.reset()
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for s in generator_samples[:-1]:
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generator.rollout_buffer.add(
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obs=s['obs'],
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action=s['action'].cpu(),
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reward=s['reward'].cpu(),
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episode_start=s['episode_start'],
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value=s['value'],
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log_prob=s['log_prob'],
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)
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generator.rollout_buffer.compute_returns_and_advantage(
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last_values=generator_samples[-1]['value'],
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dones=generator_samples[-1]['done'],
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)
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generator.train()
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class OptionsEnv(gym.Wrapper):
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def __init__(self, env):
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super().__init__(env)
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num_hl_options = len(ALL_OPTIONS)
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self.action_space = gym.spaces.Discrete(num_hl_options)
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self.observation_space = gym.spaces.Dict({
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'obs': env.observation_space,
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'mask': gym.spaces.Box(low=0, high=1, shape=(num_hl_options,)),
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})
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def train(expert_data, epochs=10, expert_batch_size=32, generator_steps=2048):
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env = NRasterized(**env_settings)
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tempdir = tempfile.TemporaryDirectory(prefix="quickstart")
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tempdir_path = pathlib.Path(tempdir.name)
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logger.configure(tempdir_path / "GAIL/")
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print(f"All Tensorboards and logging are being written inside {tempdir_path}/.")
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venv = make_vec_env(NRasterized, n_envs=1, env_kwargs=env_settings)
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discriminator = adversarial.GAIL(
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expert_data=expert_data,
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expert_batch_size=expert_batch_size,
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discrim_kwargs={'discrim_net': CnnDiscriminator(venv)},
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venv=venv, # unused
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gen_algo=stable_baselines3.PPO("CnnPolicy", venv), # unused
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)
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generator = stable_baselines3.PPO(
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OptionsCnnPolicy,
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OptionsEnv(env),
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verbose=1,
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n_steps=generator_steps,
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)
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# PPO.train requires logger as set up in
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# PPO._setup_learn (called by PPO.learn)
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generator._logger = stable_baselines3.common.utils.configure_logger(
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generator.verbose,
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generator.tensorboard_log,
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)
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for _ in range(epochs):
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train_discriminator(env, generator, discriminator, num_samples=expert_batch_size)
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train_generator(env, generator, discriminator, num_samples=generator_steps)
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return generator
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# %%
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if __name__ == '__main__':
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# %%
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with open("data/NormalizedIntersimpleExpertMu.001_NRasterizedAgent51w36h36mppx2.pkl", "rb") as f:
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trajectories = pickle.load(f)
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transitions = rollout.flatten_trajectories(trajectories)
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generator = train(transitions, generator_steps=200)
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generator.save(model_name)
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# %%
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model = stable_baselines3.PPO.load(model_name)
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env = NRasterized(**env_settings)
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s = env.reset()
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done = False
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env.render()
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while not done:
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m = available_actions(env)
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ch, _, _ = generator.policy.predict({
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'obs': torch.tensor(s).unsqueeze(0).to(generator.policy.device),
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'mask': torch.tensor(m).unsqueeze(0).to(generator.policy.device),
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})
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plan = list(map(float, generate_plan(env, ch)))
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while not done and plan and feasible(env, plan, ch):
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a, plan = env._normalize(plan[0]), plan[1:]
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s, _, done, _ = env.step(a)
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env.render()
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env.close(filestr='render/'+model_name)
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# %% Tests
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def test_ll_transitions_vs_expert_data():
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with open("data/NormalizedIntersimpleExpertMu.001_NRasterizedAgent51w36h36mppx2.pkl", "rb") as f:
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expert_trajectories = pickle.load(f)
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expert_transitions = rollout.flatten_trajectories(expert_trajectories)
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env = NRasterized(agent=51, width=36, height=36, m_per_px=2)
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gen_transitions = list(itertools.islice(sample_ll(
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env=NRasterized(**env_settings),
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generator=stable_baselines3.PPO(
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OptionsCnnPolicy,
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OptionsEnv(env),
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verbose=1,
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)
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), 10))
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gen_transitions = flatten_transitions(gen_transitions)
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assert expert_transitions[:10].obs.shape == gen_transitions['obs'].shape
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assert expert_transitions[:10].next_obs.shape == gen_transitions['next_obs'].shape
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assert expert_transitions[:10].acts.shape == gen_transitions['acts'].shape
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assert expert_transitions[:10].dones.shape == gen_transitions['dones'].shape
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def test_hl_transitions():
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pass
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