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dqn.py
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dqn.py
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import tensorflow as tf
import tensorflow.keras.losses as kls
import tensorflow.keras.optimizers as ko
import tensorflow.keras.layers as kl
import numpy as np
import logging
import datetime
import os
import random
import math
from replayMemory import ReplayMemory
def CarModel(num_actions, input_len):
input = kl.Input(shape=(input_len))
hidden1 = kl.Dense(128, activation='relu')(input)
hidden2 = kl.Dense(256, activation='relu')(hidden1)
hidden3 = kl.Dense(128, activation='relu')(hidden2)
state_value = kl.Dense(1)(hidden3)
state_value = kl.Lambda(lambda s: tf.keras.backend.expand_dims(s[:, 0], -1), output_shape=(num_actions,))(state_value)
action_advantage = kl.Dense(num_actions)(hidden3)
action_advantage = kl.Lambda(lambda a: a[:, :] - tf.keras.backend.mean(a[:, :], keepdims=True), output_shape=(num_actions,))(
action_advantage)
X = kl.Add()([state_value, action_advantage])
model = tf.keras.models.Model(input, X, name='CarModel')
return model
class DQModel(tf.keras.Model):
def __init__(self, hidden_size=128, num_actions=3):
super(DQModel, self).__init__()
self.dense1 = kl.Dense(hidden_size, activation='relu')
self.dense2 = kl.Dense(hidden_size, activation='relu')
self.adv_dense = kl.Dense(hidden_size, activation='relu')
self.adv_out = kl.Dense(num_actions)
self.v_dense = kl.Dense(hidden_size, activation='relu')
self.v_out = kl.Dense(1)
self.lambda_layer = kl.Lambda(lambda x: x - tf.reduce_mean(x))
self.combine = kl.Add()
def call(self, input):
x = self.dense1(input)
x = self.dense2(x)
adv = self.adv_dense(x)
adv = self.adv_out(adv)
v = self.v_dense(x)
v = self.v_out(v)
norm_adv = self.lambda_layer(adv)
combined = self.combine([v, norm_adv])
return combined
class DQNAgent:
def __init__(self, fn=None, lr=0.001, gamma=0.95, batch_size=32):
# Coefficients are used for the loss terms.
self.gamma = gamma
self.lr = lr
self.current_time = datetime.datetime.now().strftime("%Y%m%d-%H%M%S")
self.checkpoint_dir = 'checkpoints/'
self.model_name = 'DQN'
self.model_dir = self.checkpoint_dir + self.model_name
self.log_dir = 'logs/'
self.train_log_dir = self.log_dir + self.model_name
self.create_log_dir()
self.train_summary_writer = tf.summary.create_file_writer(self.train_log_dir)
self.fn = fn
self.EPS_START = 0.9
self.EPS_END = 0.5
self.steps_done = 0
self.EPS_DECAY = 100
self.steps_done = 0
self.batch_size = batch_size
self.TAU = 0.08
# Parameter updates
self.loss = tf.keras.losses.Huber()
self.optimizer = tf.optimizers.Adam(learning_rate=self.lr)
self.main_network = CarModel(num_actions=3, input_len=37)
self.target_network = CarModel(num_actions=3, input_len=37)
def create_log_dir(self):
if not os.path.exists(self.log_dir):
os.mkdir(self.log_dir)
if not os.path.exists(self.train_log_dir):
os.mkdir(self.train_log_dir)
if not os.path.exists(self.checkpoint_dir):
os.mkdir(self.checkpoint_dir)
if not os.path.exists(self.model_dir):
os.mkdir(self.model_dir)
def act(self, state, main_network):
# we need to do exploration vs exploitation
eps_threshold = self.EPS_END + (self.EPS_START - self.EPS_END) * \
math.exp(-1. * self.steps_done / self.EPS_DECAY)
if np.random.rand() < eps_threshold:
action = random.randint(0, 2)
else:
action = main_network.predict(np.expand_dims(state, axis=0))
action = np.argmax(action)
return action
def train_step_(self, replay_memory):
states, actions, rewards, new_states, terminal_flags = replay_memory.get_minibatch()
q_vals = self.main_network(new_states)
actions = np.argmax(q_vals, axis=1)
# The target network estimates the Q-values (in the next state s', new_states is passed!)
# for every transition in the minibatch
q_vals = self.target_network(new_states)
# Bellman equation. Multiplication with (1-terminal_flags) makes sure that
# if the game is over, targetQ=rewards
q_vals = np.array([q_vals[num, action] for num, action in enumerate(actions)])
target_q = rewards + (self.gamma * q_vals * (1 - terminal_flags))
loss = self.main_network.train_on_batch(states, target_q)
return loss
def update_network(self):
# update target network parameters slowly from primary network
for t, e in zip(self.main_network.trainable_variables, self.target_network.trainable_variables):
t.assign(t * (1 - self.TAU) + e * self.TAU)
def train(self, env, steps_per_epoch=128, epochs=10000):
# Every four actions a gradient descend step is performed
UPDATE_FREQ = 4
# Number of chosen actions between updating the target network.
NETW_UPDATE_FREQ = 10000
# Replay mem
REPLAY_MEMORY_START_SIZE = 33
# Create network model
self.main_network.compile(optimizer=tf.keras.optimizers.Adam(), loss='mse')
# Replay memory
my_replay_memory = ReplayMemory()
# Metrics
loss_avg = tf.keras.metrics.Mean()
train_reward_tot = tf.keras.metrics.Sum()
train_rew_comf_tot = tf.keras.metrics.Sum()
train_rew_eff_tot = tf.keras.metrics.Sum()
train_rew_safe_tot = tf.keras.metrics.Sum()
train_coll_rate = tf.keras.metrics.Mean()
train_speed_rate = tf.keras.metrics.Mean()
# Training loop: collect samples, send to optimizer, repeat updates times.
next_obs = env.reset(gui=True, numVehicles=40)
first_epoch = 0
try:
for epoch in range(first_epoch, epochs):
ep_rewards = 0
for step in range(steps_per_epoch):
# curr state
state = next_obs.copy()
# get action
action = self.act(state, self.main_network)
# do step
next_obs, rewards_info, done, collision = env.step(action)
# process obs and get rewards
avg_speed_perc = env.speed / env.target_speed
rewards_tot, R_comf, R_eff, R_safe = rewards_info
# Add experience
my_replay_memory.add_experience(action=action,
frame=next_obs,
reward=rewards_tot,
terminal=done)
# Update metrics
train_reward_tot.update_state(rewards_tot)
train_rew_comf_tot.update_state(R_comf)
train_rew_eff_tot.update_state(R_eff)
train_rew_safe_tot.update_state(R_safe)
train_coll_rate.update_state(collision)
train_speed_rate.update_state(avg_speed_perc)
# Train every UPDATE_FREQ times
if self.steps_done > REPLAY_MEMORY_START_SIZE:
loss_value = self.train_step_(my_replay_memory)
loss_avg.update_state(loss_value)
self.update_network()
else:
loss_avg.update_state(-1)
# Copy network from main to target every NETW_UPDATE_FREQ
if step % NETW_UPDATE_FREQ == 0 and step > REPLAY_MEMORY_START_SIZE:
self.target_network.set_weights(self.main_network.get_weights())
self.steps_done += 1
# Write
with self.train_summary_writer.as_default():
tf.summary.scalar('loss', loss_avg.result(), step=epoch)
tf.summary.scalar('reward_tot', train_reward_tot.result(), step=epoch)
tf.summary.scalar('rewards_comf', train_rew_comf_tot.result(), step=epoch)
tf.summary.scalar('rewards_eff', train_rew_eff_tot.result(), step=epoch)
tf.summary.scalar('rewards_safe', train_rew_safe_tot.result(), step=epoch)
tf.summary.scalar('collission_rate', train_coll_rate.result(), step=epoch)
tf.summary.scalar('avg speed wrt maximum', train_speed_rate.result(), step=epoch)
# Reset
train_reward_tot.reset_states()
train_rew_comf_tot.reset_states()
train_rew_eff_tot.reset_states()
train_rew_safe_tot.reset_states()
train_coll_rate.reset_states()
train_speed_rate.reset_states()
# Save model
if epoch % 1000 == 0:
tf.keras.models.save_model(self.main_network, self.model_dir + "/" + str(epoch) + "_main_network.hp5", save_format="h5")
tf.keras.models.save_model(self.target_network, self.model_dir + "/" + str(epoch) + "_target_network.hp5", save_format="h5")
except KeyboardInterrupt:
# self.model.save_weights(self.model_dir+"/model.ckpt")
tf.keras.models.save_model(self.main_network, self.model_dir + "/" + str(epoch) + "_main_network.hp5", save_format="h5")
tf.keras.models.save_model(self.target_network, self.model_dir + "/" + str(epoch) + "_target_network.hp5", save_format="h5")
env.close()
return 0