import logging
import numpy as np
import tensorflow as tf
import tensorflow.contrib.layers as c_layers
logger = logging.getLogger("unityagents")
class LearningModel(object):
def __init__(self, m_size, normalize, use_recurrent, brain):
self.brain = brain
self.vector_in = None
self.normalize = False
self.use_recurrent = False
self.global_step, self.increment_step = self.create_global_steps()
self.visual_in = []
self.batch_size = tf.placeholder(shape=None, dtype=tf.int32, name='batch_size')
self.sequence_length = tf.placeholder(shape=None, dtype=tf.int32, name='sequence_length')
self.m_size = m_size
self.normalize = normalize
self.use_recurrent = use_recurrent
self.a_size = brain.vector_action_space_size
@staticmethod
def create_global_steps():
"""Creates TF ops to track and increment global training step."""
global_step = tf.Variable(0, name="global_step", trainable=False, dtype=tf.int32)
increment_step = tf.assign(global_step, tf.add(global_step, 1))
return global_step, increment_step
@staticmethod
def swish(input_activation):
"""Swish activation function. For more info: https://arxiv.org/abs/1710.05941"""
return tf.multiply(input_activation, tf.nn.sigmoid(input_activation))
@staticmethod
def create_visual_input(o_size_h, o_size_w, bw, name):
if bw:
c_channels = 1
else:
c_channels = 3
visual_in = tf.placeholder(shape=[None, o_size_h, o_size_w, c_channels], dtype=tf.float32, name=name)
return visual_in
def create_vector_input(self, s_size):
if self.brain.vector_observation_space_type == "continuous":
self.vector_in = tf.placeholder(shape=[None, s_size], dtype=tf.float32, name='vector_observation')
if self.normalize:
self.running_mean = tf.get_variable("running_mean", [s_size], trainable=False, dtype=tf.float32,
initializer=tf.zeros_initializer())
self.running_variance = tf.get_variable("running_variance", [s_size], trainable=False, dtype=tf.float32,
initializer=tf.ones_initializer())
self.new_mean = tf.placeholder(shape=[s_size], dtype=tf.float32, name='new_mean')
self.new_variance = tf.placeholder(shape=[s_size], dtype=tf.float32, name='new_variance')
self.update_mean = tf.assign(self.running_mean, self.new_mean)
self.update_variance = tf.assign(self.running_variance, self.new_variance)
self.normalized_state = tf.clip_by_value((self.vector_in - self.running_mean) / tf.sqrt(
self.running_variance / (tf.cast(self.global_step, tf.float32) + 1)), -5, 5,
name="normalized_state")
else:
self.normalized_state = self.vector_in
else:
self.vector_in = tf.placeholder(shape=[None, 1], dtype=tf.int32, name='vector_observation')
def create_continuous_state_encoder(self, h_size, activation, num_layers):
"""
Builds a set of hidden state encoders.
:param h_size: Hidden layer size.
:param activation: What type of activation function to use for layers.
:param num_layers: number of hidden layers to create.
:return: List of hidden layer tensors.
"""
hidden = self.normalized_state
for j in range(num_layers):
hidden = tf.layers.dense(hidden, h_size, activation=activation,
kernel_initializer=c_layers.variance_scaling_initializer(1.0))
return hidden
def create_visual_encoder(self, h_size, activation, num_layers):
"""
Builds a set of visual (CNN) encoders.
:param h_size: Hidden layer size.
:param activation: What type of activation function to use for layers.
:param num_layers: number of hidden layers to create.
:return: List of hidden layer tensors.
"""
conv1 = tf.layers.conv2d(self.visual_in[-1], 16, kernel_size=[8, 8], strides=[4, 4],
activation=tf.nn.elu)
conv2 = tf.layers.conv2d(conv1, 32, kernel_size=[4, 4], strides=[2, 2],
activation=tf.nn.elu)
hidden = c_layers.flatten(conv2)
for j in range(num_layers):
hidden = tf.layers.dense(hidden, h_size, use_bias=False, activation=activation)
return hidden
def create_discrete_state_encoder(self, s_size, h_size, activation, num_layers):
"""
Builds a set of hidden state encoders from discrete state input.
:param s_size: state input size (discrete).
:param h_size: Hidden layer size.
:param activation: What type of activation function to use for layers.
:param num_layers: number of hidden layers to create.
:return: List of hidden layer tensors.
"""
vector_in = tf.reshape(self.vector_in, [-1])
state_onehot = c_layers.one_hot_encoding(vector_in, s_size)
hidden = state_onehot
for j in range(num_layers):
hidden = tf.layers.dense(hidden, h_size, use_bias=False, activation=activation)
return hidden
def create_new_obs(self, num_streams, h_size, num_layers):
brain = self.brain
s_size = brain.vector_observation_space_size * brain.num_stacked_vector_observations
if brain.vector_action_space_type == "continuous":
activation_fn = tf.nn.tanh
else:
activation_fn = self.swish
self.visual_in = []
for i in range(brain.number_visual_observations):
height_size, width_size = brain.camera_resolutions[i]['height'], brain.camera_resolutions[i]['width']
bw = brain.camera_resolutions[i]['blackAndWhite']
visual_input = self.create_visual_input(height_size, width_size, bw, name="visual_observation_" + str(i))
self.visual_in.append(visual_input)
self.create_vector_input(s_size)
final_hiddens = []
for i in range(num_streams):
visual_encoders = []
hidden_state, hidden_visual = None, None
if brain.number_visual_observations > 0:
for j in range(brain.number_visual_observations):
encoded_visual = self.create_visual_encoder(h_size, activation_fn, num_layers)
visual_encoders.append(encoded_visual)
hidden_visual = tf.concat(visual_encoders, axis=1)
if brain.vector_observation_space_size > 0:
s_size = brain.vector_observation_space_size * brain.num_stacked_vector_observations
if brain.vector_observation_space_type == "continuous":
hidden_state = self.create_continuous_state_encoder(h_size, activation_fn, num_layers)
else:
hidden_state = self.create_discrete_state_encoder(s_size, h_size,
activation_fn, num_layers)
if hidden_state is not None and hidden_visual is not None:
final_hidden = tf.concat([hidden_visual, hidden_state], axis=1)
elif hidden_state is None and hidden_visual is not None:
final_hidden = hidden_visual
elif hidden_state is not None and hidden_visual is None:
final_hidden = hidden_state
else:
raise Exception("No valid network configuration possible. "
"There are no states or observations in this brain")
final_hiddens.append(final_hidden)
return final_hiddens
def create_recurrent_encoder(self, input_state, memory_in, name='lstm'):
"""
Builds a recurrent encoder for either state or observations (LSTM).
:param input_state: The input tensor to the LSTM cell.
:param memory_in: The input memory to the LSTM cell.
:param name: The scope of the LSTM cell.
"""
s_size = input_state.get_shape().as_list()[1]
m_size = memory_in.get_shape().as_list()[1]
lstm_input_state = tf.reshape(input_state, shape=[-1, self.sequence_length, s_size])
_half_point = int(m_size / 2)
with tf.variable_scope(name):
rnn_cell = tf.contrib.rnn.BasicLSTMCell(_half_point)
lstm_vector_in = tf.contrib.rnn.LSTMStateTuple(memory_in[:, :_half_point], memory_in[:, _half_point:])
recurrent_state, lstm_state_out = tf.nn.dynamic_rnn(rnn_cell, lstm_input_state,
initial_state=lstm_vector_in,
time_major=False,
dtype=tf.float32)
recurrent_state = tf.reshape(recurrent_state, shape=[-1, _half_point])
return recurrent_state, tf.concat([lstm_state_out.c, lstm_state_out.h], axis=1)
def create_dc_actor_critic(self, h_size, num_layers):
num_streams = 1
hidden_streams = self.create_new_obs(num_streams, h_size, num_layers)
hidden = hidden_streams[0]
if self.use_recurrent:
tf.Variable(self.m_size, name="memory_size", trainable=False, dtype=tf.int32)
self.prev_action = tf.placeholder(shape=[None], dtype=tf.int32, name='prev_action')
self.prev_action_oh = c_layers.one_hot_encoding(self.prev_action, self.a_size)
hidden = tf.concat([hidden, self.prev_action_oh], axis=1)
self.memory_in = tf.placeholder(shape=[None, self.m_size], dtype=tf.float32, name='recurrent_in')
hidden, self.memory_out = self.create_recurrent_encoder(hidden, self.memory_in)
self.memory_out = tf.identity(self.memory_out, name='recurrent_out')
self.policy = tf.layers.dense(hidden, self.a_size, activation=None, use_bias=False,
kernel_initializer=c_layers.variance_scaling_initializer(factor=0.01))
self.all_probs = tf.nn.softmax(self.policy, name="action_probs")
self.output = tf.multinomial(self.policy, 1)
self.output = tf.identity(self.output, name="action")
self.value = tf.layers.dense(hidden, 1, activation=None)
self.value = tf.identity(self.value, name="value_estimate")
self.entropy = -tf.reduce_sum(self.all_probs * tf.log(self.all_probs + 1e-10), axis=1)
self.action_holder = tf.placeholder(shape=[None], dtype=tf.int32)
self.selected_actions = c_layers.one_hot_encoding(self.action_holder, self.a_size)
self.all_old_probs = tf.placeholder(shape=[None, self.a_size], dtype=tf.float32, name='old_probabilities')
# We reshape these tensors to [batch x 1] in order to be of the same rank as continuous control probabilities.
self.probs = tf.expand_dims(tf.reduce_sum(self.all_probs * self.selected_actions, axis=1), 1)
self.old_probs = tf.expand_dims(tf.reduce_sum(self.all_old_probs * self.selected_actions, axis=1), 1)
def create_cc_actor_critic(self, h_size, num_layers):
num_streams = 2
hidden_streams = self.create_new_obs(num_streams, h_size, num_layers)
if self.use_recurrent:
tf.Variable(self.m_size, name="memory_size", trainable=False, dtype=tf.int32)
self.memory_in = tf.placeholder(shape=[None, self.m_size], dtype=tf.float32, name='recurrent_in')
_half_point = int(self.m_size / 2)
hidden_policy, memory_policy_out = self.create_recurrent_encoder(
hidden_streams[0], self.memory_in[:, :_half_point], name='lstm_policy')
hidden_value, memory_value_out = self.create_recurrent_encoder(
hidden_streams[1], self.memory_in[:, _half_point:], name='lstm_value')
self.memory_out = tf.concat([memory_policy_out, memory_value_out], axis=1, name='recurrent_out')
else:
hidden_policy = hidden_streams[0]
hidden_value = hidden_streams[1]
self.mu = tf.layers.dense(hidden_policy, self.a_size, activation=None, use_bias=False,
kernel_initializer=c_layers.variance_scaling_initializer(factor=0.01))
self.log_sigma_sq = tf.get_variable("log_sigma_squared", [self.a_size], dtype=tf.float32,
initializer=tf.zeros_initializer())
self.sigma_sq = tf.exp(self.log_sigma_sq)
self.epsilon = tf.random_normal(tf.shape(self.mu), dtype=tf.float32)
self.output = self.mu + tf.sqrt(self.sigma_sq) * self.epsilon
self.output = tf.identity(self.output, name='action')
a = tf.exp(-1 * tf.pow(tf.stop_gradient(self.output) - self.mu, 2) / (2 * self.sigma_sq))
b = 1 / tf.sqrt(2 * self.sigma_sq * np.pi)
self.all_probs = tf.multiply(a, b, name="action_probs")
self.entropy = tf.reduce_mean(0.5 * tf.log(2 * np.pi * np.e * self.sigma_sq))
self.value = tf.layers.dense(hidden_value, 1, activation=None)
self.value = tf.identity(self.value, name="value_estimate")
self.all_old_probs = tf.placeholder(shape=[None, self.a_size], dtype=tf.float32,
name='old_probabilities')
# We keep these tensors the same name, but use new nodes to keep code parallelism with discrete control.
self.probs = tf.identity(self.all_probs)
self.old_probs = tf.identity(self.all_old_probs)
