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ray/python/ray/rllib/evolution_strategies/evolution_strategies.py
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Eric LiangandPhilipp Moritz 420013774c [rllib] Pull out shared models for evolution strategies and policy gradient. (#719)
* wip

* works with cartpole

* lint

* fix pg

* comment

* action dist rename

* preprocessor

* fix test

* typo

* fix the action[0] nonsense

* revert

* satisfy the lint

* wip

* works with cartpole

* lint

* fix pg

* comment

* action dist rename

* preprocessor

* fix test

* typo

* fix the action[0] nonsense

* revert

* satisfy the lint

* Minor indentation changes.

* fix merge

* add humanoid

* fix linting

* more 4 space

* fix

* fix linT

* oops

* es parity
2017-07-17 08:58:54 +00:00

322 lines
12 KiB
Python

# Code in this file is copied and adapted from
# https://github.com/openai/evolution-strategies-starter.
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from collections import namedtuple
import gym
import numpy as np
import os
import time
import ray
from ray.rllib.common import Algorithm, TrainingResult
from ray.rllib.evolution_strategies import optimizers
from ray.rllib.evolution_strategies import policies
from ray.rllib.evolution_strategies import tabular_logger as tlogger
from ray.rllib.evolution_strategies import tf_util
from ray.rllib.evolution_strategies import utils
Result = namedtuple("Result", [
"noise_inds_n", "returns_n2", "sign_returns_n2", "lengths_n2",
"eval_return", "eval_length", "ob_sum", "ob_sumsq", "ob_count"
])
DEFAULT_CONFIG = dict(
l2coeff=0.005,
noise_stdev=0.02,
episodes_per_batch=1000,
timesteps_per_batch=10000,
calc_obstat_prob=0.01,
eval_prob=0,
snapshot_freq=0,
return_proc_mode="centered_rank",
episode_cutoff_mode="env_default",
num_workers=10,
stepsize=.01)
@ray.remote
def create_shared_noise():
"""Create a large array of noise to be shared by all workers."""
seed = 123
count = 250000000
noise = np.random.RandomState(seed).randn(count).astype(np.float32)
return noise
class SharedNoiseTable(object):
def __init__(self, noise):
self.noise = noise
assert self.noise.dtype == np.float32
def get(self, i, dim):
return self.noise[i:i + dim]
def sample_index(self, stream, dim):
return stream.randint(0, len(self.noise) - dim + 1)
@ray.remote
class Worker(object):
def __init__(self, config, policy_params, env_name, noise,
min_task_runtime=0.2):
self.min_task_runtime = min_task_runtime
self.config = config
self.policy_params = policy_params
self.noise = SharedNoiseTable(noise)
self.env = gym.make(env_name)
self.sess = utils.make_session(single_threaded=True)
self.policy = policies.GenericPolicy(
self.env.observation_space, self.env.action_space, **policy_params)
tf_util.initialize()
self.rs = np.random.RandomState()
assert (
self.policy.needs_ob_stat ==
(self.config["calc_obstat_prob"] != 0))
def rollout_and_update_ob_stat(self, timestep_limit, task_ob_stat):
if (self.policy.needs_ob_stat and
self.config["calc_obstat_prob"] != 0 and
self.rs.rand() < self.config["calc_obstat_prob"]):
rollout_rews, rollout_len, obs = self.policy.rollout(
self.env, timestep_limit=timestep_limit, save_obs=True,
random_stream=self.rs)
task_ob_stat.increment(obs.sum(axis=0), np.square(obs).sum(axis=0),
len(obs))
else:
rollout_rews, rollout_len = self.policy.rollout(
self.env, timestep_limit=timestep_limit, random_stream=self.rs)
return rollout_rews, rollout_len
def do_rollouts(self, params, ob_mean, ob_std, timestep_limit=None):
# Set the network weights.
self.policy.set_trainable_flat(params)
if self.policy.needs_ob_stat:
self.policy.set_ob_stat(ob_mean, ob_std)
if self.config["eval_prob"] != 0:
raise NotImplementedError("Eval rollouts are not implemented.")
noise_inds, returns, sign_returns, lengths = [], [], [], []
# We set eps=0 because we're incrementing only.
task_ob_stat = utils.RunningStat(
self.env.observation_space.shape, eps=0)
# Perform some rollouts with noise.
task_tstart = time.time()
while (len(noise_inds) == 0 or
time.time() - task_tstart < self.min_task_runtime):
noise_idx = self.noise.sample_index(
self.rs, self.policy.num_params)
perturbation = self.config["noise_stdev"] * self.noise.get(
noise_idx, self.policy.num_params)
# These two sampling steps could be done in parallel on different
# actors letting us update twice as frequently.
self.policy.set_trainable_flat(params + perturbation)
rews_pos, len_pos = self.rollout_and_update_ob_stat(timestep_limit,
task_ob_stat)
self.policy.set_trainable_flat(params - perturbation)
rews_neg, len_neg = self.rollout_and_update_ob_stat(timestep_limit,
task_ob_stat)
noise_inds.append(noise_idx)
returns.append([rews_pos.sum(), rews_neg.sum()])
sign_returns.append(
[np.sign(rews_pos).sum(), np.sign(rews_neg).sum()])
lengths.append([len_pos, len_neg])
return Result(
noise_inds_n=np.array(noise_inds),
returns_n2=np.array(returns, dtype=np.float32),
sign_returns_n2=np.array(sign_returns, dtype=np.float32),
lengths_n2=np.array(lengths, dtype=np.int32),
eval_return=None,
eval_length=None,
ob_sum=(None if task_ob_stat.count == 0 else task_ob_stat.sum),
ob_sumsq=(None if task_ob_stat.count == 0
else task_ob_stat.sumsq),
ob_count=task_ob_stat.count)
class EvolutionStrategies(Algorithm):
def __init__(self, env_name, config, upload_dir=None):
config.update({"alg": "EvolutionStrategies"})
Algorithm.__init__(self, env_name, config, upload_dir=upload_dir)
policy_params = {
"ac_noise_std": 0.01
}
env = gym.make(env_name)
utils.make_session(single_threaded=False)
self.policy = policies.GenericPolicy(
env.observation_space, env.action_space, **policy_params)
tf_util.initialize()
self.optimizer = optimizers.Adam(self.policy, config["stepsize"])
self.ob_stat = utils.RunningStat(env.observation_space.shape, eps=1e-2)
# Create the shared noise table.
print("Creating shared noise table.")
noise_id = create_shared_noise.remote()
self.noise = SharedNoiseTable(ray.get(noise_id))
# Create the actors.
print("Creating actors.")
self.workers = [
Worker.remote(config, policy_params, env_name, noise_id)
for _ in range(config["num_workers"])]
self.episodes_so_far = 0
self.timesteps_so_far = 0
self.tstart = time.time()
self.iteration = 0
def _collect_results(self, theta_id, min_eps, min_timesteps):
num_eps, num_timesteps = 0, 0
results = []
while num_eps < min_eps or num_timesteps < min_timesteps:
print(
"Collected {} episodes {} timesteps so far this iter".format(
num_eps, num_timesteps))
rollout_ids = [worker.do_rollouts.remote(
theta_id,
self.ob_stat.mean if self.policy.needs_ob_stat else None,
self.ob_stat.std if self.policy.needs_ob_stat else None)
for worker in self.workers]
# Get the results of the rollouts.
for result in ray.get(rollout_ids):
results.append(result)
num_eps += result.lengths_n2.size
num_timesteps += result.lengths_n2.sum()
return results
def train(self):
config = self.config
step_tstart = time.time()
theta = self.policy.get_trainable_flat()
assert theta.dtype == np.float32
# Put the current policy weights in the object store.
theta_id = ray.put(theta)
# Use the actors to do rollouts, note that we pass in the ID of the
# policy weights.
results = self._collect_results(
theta_id,
config["episodes_per_batch"],
config["timesteps_per_batch"])
curr_task_results = []
ob_count_this_batch = 0
# Loop over the results
for result in results:
assert result.eval_length is None, "We aren't doing eval rollouts."
assert result.noise_inds_n.ndim == 1
assert result.returns_n2.shape == (len(result.noise_inds_n), 2)
assert result.lengths_n2.shape == (len(result.noise_inds_n), 2)
assert result.returns_n2.dtype == np.float32
result_num_eps = result.lengths_n2.size
result_num_timesteps = result.lengths_n2.sum()
self.episodes_so_far += result_num_eps
self.timesteps_so_far += result_num_timesteps
curr_task_results.append(result)
# Update ob stats.
if self.policy.needs_ob_stat and result.ob_count > 0:
self.ob_stat.increment(
result.ob_sum, result.ob_sumsq, result.ob_count)
ob_count_this_batch += result.ob_count
# Assemble the results.
noise_inds_n = np.concatenate(
[r.noise_inds_n for r in curr_task_results])
returns_n2 = np.concatenate([r.returns_n2 for r in curr_task_results])
lengths_n2 = np.concatenate([r.lengths_n2 for r in curr_task_results])
assert (noise_inds_n.shape[0] == returns_n2.shape[0] ==
lengths_n2.shape[0])
# Process the returns.
if config["return_proc_mode"] == "centered_rank":
proc_returns_n2 = utils.compute_centered_ranks(returns_n2)
else:
raise NotImplementedError(config["return_proc_mode"])
# Compute and take a step.
g, count = utils.batched_weighted_sum(
proc_returns_n2[:, 0] - proc_returns_n2[:, 1],
(self.noise.get(idx, self.policy.num_params)
for idx in noise_inds_n),
batch_size=500)
g /= returns_n2.size
assert (
g.shape == (self.policy.num_params,) and
g.dtype == np.float32 and
count == len(noise_inds_n))
update_ratio = self.optimizer.update(-g + config["l2coeff"] * theta)
# Update ob stat (we're never running the policy in the master, but we
# might be snapshotting the policy).
if self.policy.needs_ob_stat:
self.policy.set_ob_stat(self.ob_stat.mean, self.ob_stat.std)
step_tend = time.time()
tlogger.record_tabular("EpRewMean", returns_n2.mean())
tlogger.record_tabular("EpRewStd", returns_n2.std())
tlogger.record_tabular("EpLenMean", lengths_n2.mean())
tlogger.record_tabular(
"Norm", float(np.square(self.policy.get_trainable_flat()).sum()))
tlogger.record_tabular("GradNorm", float(np.square(g).sum()))
tlogger.record_tabular("UpdateRatio", float(update_ratio))
tlogger.record_tabular("EpisodesThisIter", lengths_n2.size)
tlogger.record_tabular("EpisodesSoFar", self.episodes_so_far)
tlogger.record_tabular("TimestepsThisIter", lengths_n2.sum())
tlogger.record_tabular("TimestepsSoFar", self.timesteps_so_far)
tlogger.record_tabular("ObCount", ob_count_this_batch)
tlogger.record_tabular("TimeElapsedThisIter", step_tend - step_tstart)
tlogger.record_tabular("TimeElapsed", step_tend - self.tstart)
tlogger.dump_tabular()
if (config["snapshot_freq"] != 0 and
self.iteration % config["snapshot_freq"] == 0):
filename = os.path.join(
self.logdir, "snapshot_iter{:05d}.h5".format(self.iteration))
assert not os.path.exists(filename)
self.policy.save(filename)
tlogger.log("Saved snapshot {}".format(filename))
info = {
"weights_norm": np.square(self.policy.get_trainable_flat()).sum(),
"grad_norm": np.square(g).sum(),
"update_ratio": update_ratio,
"episodes_this_iter": lengths_n2.size,
"episodes_so_far": self.episodes_so_far,
"timesteps_this_iter": lengths_n2.sum(),
"timesteps_so_far": self.timesteps_so_far,
"ob_count": ob_count_this_batch,
"time_elapsed_this_iter": step_tend - step_tstart,
"time_elapsed": step_tend - self.tstart
}
res = TrainingResult(self.experiment_id.hex, self.iteration,
returns_n2.mean(), lengths_n2.mean(), info)
self.iteration += 1
return res