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#@title Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
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tf_agents.utils.common.Checkpointer is a utility to save/load the training state, policy state, and replay_buffer state to/from a local storage.
tf_agents.policies.policy_saver.PolicySaver is a tool to save/load only the policy, and is lighter than Checkpointer. You can use PolicySaver to deploy the model as well without any knowledge of the code that created the policy.
In this tutorial, we will use DQN to train a model, then use Checkpointer and PolicySaver to show how we can store and load the states and model in an interactive way. Note that we will use TF2.0's new saved_model tooling and format for PolicySaver.
If you haven't installed the following dependencies, run:
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#@test {"skip": true}
!sudo apt-get install -y xvfb ffmpeg
!pip install 'gym==0.10.11'
!pip install 'imageio==2.4.0'
!pip install 'pyglet==1.3.2'
!pip install 'xvfbwrapper==0.2.9'
!pip install --pre tf-agents[reverb]
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from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import base64
import imageio
import io
import matplotlib
import matplotlib.pyplot as plt
import os
import shutil
import tempfile
import tensorflow as tf
import zipfile
import IPython
try:
from google.colab import files
except ImportError:
files = None
from tf_agents.agents.dqn import dqn_agent
from tf_agents.drivers import dynamic_step_driver
from tf_agents.environments import suite_gym
from tf_agents.environments import tf_py_environment
from tf_agents.eval import metric_utils
from tf_agents.metrics import tf_metrics
from tf_agents.networks import q_network
from tf_agents.policies import policy_saver
from tf_agents.policies import py_tf_eager_policy
from tf_agents.policies import random_tf_policy
from tf_agents.replay_buffers import tf_uniform_replay_buffer
from tf_agents.trajectories import trajectory
from tf_agents.utils import common
tf.compat.v1.enable_v2_behavior()
tempdir = os.getenv("TEST_TMPDIR", tempfile.gettempdir())
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#@test {"skip": true}
# Set up a virtual display for rendering OpenAI gym environments.
import xvfbwrapper
xvfbwrapper.Xvfb(1400, 900, 24).start()
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env_name = "CartPole-v1"
collect_steps_per_iteration = 100
replay_buffer_capacity = 100000
fc_layer_params = (100,)
batch_size = 64
learning_rate = 1e-3
log_interval = 5
num_eval_episodes = 10
eval_interval = 1000
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train_py_env = suite_gym.load(env_name)
eval_py_env = suite_gym.load(env_name)
train_env = tf_py_environment.TFPyEnvironment(train_py_env)
eval_env = tf_py_environment.TFPyEnvironment(eval_py_env)
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#@title
q_net = q_network.QNetwork(
train_env.observation_spec(),
train_env.action_spec(),
fc_layer_params=fc_layer_params)
optimizer = tf.compat.v1.train.AdamOptimizer(learning_rate=learning_rate)
global_step = tf.compat.v1.train.get_or_create_global_step()
agent = dqn_agent.DqnAgent(
train_env.time_step_spec(),
train_env.action_spec(),
q_network=q_net,
optimizer=optimizer,
td_errors_loss_fn=common.element_wise_squared_loss,
train_step_counter=global_step)
agent.initialize()
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#@title
replay_buffer = tf_uniform_replay_buffer.TFUniformReplayBuffer(
data_spec=agent.collect_data_spec,
batch_size=train_env.batch_size,
max_length=replay_buffer_capacity)
collect_driver = dynamic_step_driver.DynamicStepDriver(
train_env,
agent.collect_policy,
observers=[replay_buffer.add_batch],
num_steps=collect_steps_per_iteration)
# Initial data collection
collect_driver.run()
# Dataset generates trajectories with shape [BxTx...] where
# T = n_step_update + 1.
dataset = replay_buffer.as_dataset(
num_parallel_calls=3, sample_batch_size=batch_size,
num_steps=2).prefetch(3)
iterator = iter(dataset)
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#@title
# (Optional) Optimize by wrapping some of the code in a graph using TF function.
agent.train = common.function(agent.train)
def train_one_iteration():
# Collect a few steps using collect_policy and save to the replay buffer.
for _ in range(collect_steps_per_iteration):
collect_driver.run()
# Sample a batch of data from the buffer and update the agent's network.
experience, unused_info = next(iterator)
train_loss = agent.train(experience)
iteration = agent.train_step_counter.numpy()
print ('iteration: {0} loss: {1}'.format(iteration, train_loss.loss))
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#@title
def embed_gif(gif_buffer):
"""Embeds a gif file in the notebook."""
tag = '<img src="data:image/gif;base64,{0}"/>'.format(base64.b64encode(gif_buffer).decode())
return IPython.display.HTML(tag)
def run_episodes_and_create_video(policy, eval_tf_env, eval_py_env):
num_episodes = 3
frames = []
for _ in range(num_episodes):
time_step = eval_tf_env.reset()
frames.append(eval_py_env.render())
while not time_step.is_last():
action_step = policy.action(time_step)
time_step = eval_tf_env.step(action_step.action)
frames.append(eval_py_env.render())
gif_file = io.BytesIO()
imageio.mimsave(gif_file, frames, format='gif', fps=60)
IPython.display.display(embed_gif(gif_file.getvalue()))
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print ('global_step:')
print (global_step)
run_episodes_and_create_video(agent.policy, eval_env, eval_py_env)
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checkpoint_dir = os.path.join(tempdir, 'checkpoint')
train_checkpointer = common.Checkpointer(
ckpt_dir=checkpoint_dir,
max_to_keep=1,
agent=agent,
policy=agent.policy,
replay_buffer=replay_buffer,
global_step=global_step
)
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policy_dir = os.path.join(tempdir, 'policy')
tf_policy_saver = policy_saver.PolicySaver(agent.policy)
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#@test {"skip": true}
print('Training one iteration....')
train_one_iteration()
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train_checkpointer.save(global_step)
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train_checkpointer.initialize_or_restore()
global_step = tf.compat.v1.train.get_global_step()
Also save policy and export to a location
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tf_policy_saver.save(policy_dir)
The policy can be loaded without having any knowledge of what agent or network was used to create it. This makes deployment of the policy much easier.
Load the saved policy and check how it performs
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saved_policy = tf.compat.v2.saved_model.load(policy_dir)
run_episodes_and_create_video(saved_policy, eval_env, eval_py_env)
The rest of the colab will help you export / import checkpointer and policy directories such that you can continue training at a later point and deploy the model without having to train again.
Now you can go back to 'Train one iteration' and train a few more times such that you can understand the difference later on. Once you start to see slightly better results, continue below.
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#@title Create zip file and upload zip file (double-click to see the code)
def create_zip_file(dirname, base_filename):
return shutil.make_archive(base_filename, 'zip', dirname)
def upload_and_unzip_file_to(dirname):
if files is None:
return
uploaded = files.upload()
for fn in uploaded.keys():
print('User uploaded file "{name}" with length {length} bytes'.format(
name=fn, length=len(uploaded[fn])))
shutil.rmtree(dirname)
zip_files = zipfile.ZipFile(io.BytesIO(uploaded[fn]), 'r')
zip_files.extractall(dirname)
zip_files.close()
Create a zipped file from the checkpoint directory.
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train_checkpointer.save(global_step)
checkpoint_zip_filename = create_zip_file(checkpoint_dir, os.path.join(tempdir, 'exported_cp'))
Download the zip file.
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#@test {"skip": true}
if files is not None:
files.download(checkpoint_zip_filename) # try again if this fails: https://github.com/googlecolab/colabtools/issues/469
After training for some time (10-15 times), download the checkpoint zip file, and go to "Runtime > Restart and run all" to reset the training, and come back to this cell. Now you can upload the downloaded zip file, and continue the training.
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#@test {"skip": true}
upload_and_unzip_file_to(checkpoint_dir)
train_checkpointer.initialize_or_restore()
global_step = tf.compat.v1.train.get_global_step()
Once you have uploaded checkpoint directory, go back to 'Train one iteration' to continue training or go back to 'Generate a video' to check the performance of the loaded poliicy.
Alternatively, you can save the policy (model) and restore it. Unlike checkpointer, you cannot continue with the training, but you can still deploy the model. Note that the downloaded file is much smaller than that of the checkpointer.
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tf_policy_saver.save(policy_dir)
policy_zip_filename = create_zip_file(policy_dir, os.path.join(tempdir, 'exported_policy'))
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#@test {"skip": true}
if files is not None:
files.download(policy_zip_filename) # try again if this fails: https://github.com/googlecolab/colabtools/issues/469
Upload the downloaded policy directory (exported_policy.zip) and check how the saved policy performs.
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#@test {"skip": true}
upload_and_unzip_file_to(policy_dir)
saved_policy = tf.compat.v2.saved_model.load(policy_dir)
run_episodes_and_create_video(saved_policy, eval_env, eval_py_env)
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eager_py_policy = py_tf_eager_policy.SavedModelPyTFEagerPolicy(
policy_dir, eval_py_env.time_step_spec(), eval_py_env.action_spec())
# Note that we're passing eval_py_env not eval_env.
run_episodes_and_create_video(eager_py_policy, eval_py_env, eval_py_env)