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dynamics.py
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dynamics.py
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import numpy as np
import tensorflow as tf
from auxiliary_tasks import JustPixels
from utils import small_convnet, flatten_two_dims, unflatten_first_dim, getsess, unet
class Dynamics(object):
def __init__(self, auxiliary_task, predict_from_pixels, drop_rate, n_hidden_layers, num_estimations, feat_dim=None, scope='dynamics'):
self.scope = scope
self.auxiliary_task = auxiliary_task
self.hidsize = self.auxiliary_task.hidsize
self.feat_dim = feat_dim
self.obs = self.auxiliary_task.obs
self.last_ob = self.auxiliary_task.last_ob
self.ac = self.auxiliary_task.ac
self.ac_space = self.auxiliary_task.ac_space
self.ob_mean = self.auxiliary_task.ob_mean
self.ob_std = self.auxiliary_task.ob_std
if predict_from_pixels:
self.features = self.get_features(self.obs, reuse=False)
else:
self.features = tf.stop_gradient(self.auxiliary_task.features)
self.drop_rate = drop_rate
self.num_estimations = num_estimations
self.n_hidden_layers = n_hidden_layers
self.out_features = self.auxiliary_task.next_features
with tf.variable_scope(self.scope + "_loss"):
self.loss = self.get_loss()
def get_features(self, x, reuse):
nl = tf.nn.leaky_relu
x_has_timesteps = (x.get_shape().ndims == 5)
if x_has_timesteps:
sh = tf.shape(x)
x = flatten_two_dims(x)
with tf.variable_scope(self.scope + "_features", reuse=reuse):
x = (tf.to_float(x) - self.ob_mean) / self.ob_std
x = small_convnet(x, nl=nl, feat_dim=self.feat_dim, last_nl=nl, layernormalize=False)
if x_has_timesteps:
x = unflatten_first_dim(x, sh)
return x
def get_loss(self):
ac = tf.one_hot(self.ac, self.ac_space.n, axis=2)
sh = tf.shape(ac)
ac = flatten_two_dims(ac)
def add_ac(x):
return tf.concat([x, ac], axis=-1)
with tf.variable_scope(self.scope):
x = flatten_two_dims(self.features)
x = tf.layers.dense(add_ac(x), self.hidsize, activation=tf.nn.leaky_relu)
def residual(x):
res = tf.layers.dense(add_ac(x), self.hidsize, activation=tf.nn.leaky_relu)
res = tf.layers.dropout(x, rate=self.drop_rate, training=True)
res = tf.layers.dense(add_ac(res), self.hidsize, activation=None)
res = tf.layers.dropout(res, rate=self.drop_rate, training=True)
return x + res
for _ in range(self.n_hidden_layers):
x = residual(x)
n_out_features = self.out_features.get_shape()[-1].value
x = tf.layers.dense(add_ac(x), n_out_features, activation=None)
x = unflatten_first_dim(x, sh)
with tf.variable_scope(self.scope + "_pred"):
self.pred = tf.stop_gradient(x)
return tf.reduce_mean((x - tf.stop_gradient(self.out_features)) ** 2, -1)
def calculate_loss(self, ob, last_ob, acs):
n_chunks = 8
n = ob.shape[0]
chunk_size = n // n_chunks
assert n % n_chunks == 0
sli = lambda i: slice(i * chunk_size, (i + 1) * chunk_size)
return np.concatenate([getsess().run(self.loss,
{self.obs: ob[sli(i)], self.last_ob: last_ob[sli(i)],
self.ac: acs[sli(i)]}) for i in range(n_chunks)], 0)
def calculate_uncertainty_rew(self, ob, last_ob, acs):
preds =[]
for _ in range(self.num_estimations):
n_chunks = 8
n = ob.shape[0]
chunk_size = n // n_chunks
assert n % n_chunks == 0
sli = lambda i: slice(i * chunk_size, (i + 1) * chunk_size)
preds.append(np.concatenate([getsess().run(self.pred,
{self.obs: ob[sli(i)], self.last_ob: last_ob[sli(i)],
self.ac: acs[sli(i)]}) for i in range(n_chunks)], 0))
preds = np.stack(preds, axis=0)
return np.mean(np.std(preds, axis=0)**2, -1)
class UNet(Dynamics):
def __init__(self, auxiliary_task, predict_from_pixels, drop_rate, num_estimations, feat_dim=None, scope='pixel_dynamics'):
assert isinstance(auxiliary_task, JustPixels)
assert not predict_from_pixels, "predict from pixels must be False, it's set up to predict from features that are normalized pixels."
super(UNet, self).__init__(auxiliary_task=auxiliary_task,
predict_from_pixels=predict_from_pixels,
feat_dim=feat_dim,
scope=scope)
def get_features(self, x, reuse):
raise NotImplementedError
def get_loss(self):
nl = tf.nn.leaky_relu
ac = tf.one_hot(self.ac, self.ac_space.n, axis=2)
sh = tf.shape(ac)
ac = flatten_two_dims(ac)
ac_four_dim = tf.expand_dims(tf.expand_dims(ac, 1), 1)
def add_ac(x):
if x.get_shape().ndims == 2:
return tf.concat([x, ac], axis=-1)
elif x.get_shape().ndims == 4:
sh = tf.shape(x)
return tf.concat(
[x, ac_four_dim + tf.zeros([sh[0], sh[1], sh[2], ac_four_dim.get_shape()[3].value], tf.float32)],
axis=-1)
with tf.variable_scope(self.scope):
x = flatten_two_dims(self.features)
x = unet(x, nl=nl, feat_dim=self.feat_dim, cond=add_ac)
x = unflatten_first_dim(x, sh)
self.prediction_pixels = x * self.ob_std + self.ob_mean
return tf.reduce_mean((x - tf.stop_gradient(self.out_features)) ** 2, [2, 3, 4])