def prop_mixture(Xs, mx, xx, sx):
#comp_x = [tfd.Normal(loc=xx[j], scale=sx[j]) for j in range(n)]
# xDist = tfd.Mixture(cat=tfd.Categorical(probs=mix_cat), components=comp_x)
# xDist = tfd.Exponential( sx[0] )
mix_cat = [mx[0], 1.0 - mx[0]]
#beta = tfd.Beta(2.0, 5.0)
#beta =tfd.Normal(loc=0.0, scale=1.0)
#bijector = tfd.bijectors.AffineScalar(shift=xx[1], scale=sx[1])
#beta_shift = tfd.TransformedDistribution( distribution=beta, bijector=bijector, name="test")
#cDist = tfd.Mixture(cat=tfd.Categorical(probs=mix_cat), components=[tfd.Normal(loc=xx[0], scale=sx[0]), beta_shift])
p1 = tfd.Normal(loc=xx[0], scale=sx[0]).prob(Xs)
p2 = tf.exp(-1.0 * sx[1] * (Xs - xx[0]))
xr = tf.range(-10, 10, 0.01)
p3 = tfd.Normal(loc=xx[0], scale=sx[0]).prob(xr)
p4 = tf.exp(-sx[1] * (xr - xx[0]))
integral_ = tf.reduce_sum(tf.math.multiply(p3, p4)) / 100.0
#integral_ = 1.77 * tf.exp(mx[1] * mx[1] * 4.0)
cDist = tf.math.multiply(p1, p2) / integral_
cDist = p1 #tf.math.multiply(p1, p2) / integral_
#tf.reduce_sum(prop_mixture(tf.range(-10, 10, 0.01), mvars, xvars, svars) * 0.01))
return cDist
def sample_qH(self, H):
h_mu = H[:, :self.dim_h]
h_var = tf.exp(H[:, self.dim_h:])
qh = dist.Normal(h_mu, tf.sqrt(h_var))
ph = dist.Normal(tf.zeros_like(h_mu), tf.ones_like(h_var))
kl_h = dist.kl_divergence(qh, ph)
h_sample = qh.sample()
return h_sample, kl_h
def define_noise(batch_size_tensor, flags_obj):
# Setup noise vector
with tf.name_scope("LatentNoiseVector"):
z = tfd.Normal(loc=0.0, scale=flags_obj.stddev).sample(
sample_shape=(batch_size_tensor, flags_obj.z_dim_size))
z_perturbed = z + tfd.Normal(loc=0.0, scale=flags_obj.stddev).sample(
sample_shape=(batch_size_tensor, flags_obj.z_dim_size)) * 1e-5
return z, z_perturbed
def variational_autoencoder(features,
n_latent_dim=2,
hidden_units=[500, 500],
normalizing_flow='identity',
flow_n_iter=2,
kl_weight=1.0,
random_state=123):
features = tensor_utils.to_tensor(features, dtype=tf.float32)
kl_weight = tensor_utils.to_tensor(kl_weight, dtype=tf.float32)
n_features = tensor_utils.get_shape(features)[1]
with tf.variable_scope('inference_network'):
q_mu, q_sigma = ops.gaussian_inference_network(
x=features, n_latent_dim=n_latent_dim, hidden_units=hidden_units)
#q_mu, q_chol = ops.mvn_inference_network(x=features,
# n_latent_dim=n_latent_dim,
# hidden_units=hidden_units)
# set up the latent variables
with tf.variable_scope('latent_samples'):
with st.value_type(st.SampleValue()):
q_z = st.StochasticTensor(dist=distributions.Normal(mu=q_mu,
sigma=q_sigma),
name='q_z')
#q_z = st.StochasticTensor(
# dist=distributions.MultivariateNormalCholesky(
# mu=q_mu, chol=q_chol),
# name='q_z')
# transform the sample to a more complex density by performing
# a normalizing flow transformation
norm_flow = flow_lib.get_flow(normalizing_flow,
n_iter=flow_n_iter,
random_state=random_state)
q_z_trans, log_det_jac = norm_flow.transform(q_z, features=features)
# set up the priors
with tf.variable_scope('prior'):
prior = distributions.Normal(mu=np.zeros(n_latent_dim,
dtype=np.float32),
sigma=np.ones(n_latent_dim,
dtype=np.float32))
with tf.variable_scope('generative_network'):
p_x_given_z = ops.bernoulli_generative_network(
z=q_z_trans, hidden_units=hidden_units, n_features=n_features)
# set up elbo
log_likelihood = tf.reduce_sum(p_x_given_z.log_pmf(features), 1)
kl = tf.reduce_sum(distributions.kl(q_z.distribution, prior), 1)
neg_elbo = -tf.reduce_mean(log_likelihood + log_det_jac - kl_weight * kl,
0)
return q_mu, tf.identity(neg_elbo, name='neg_elbo')
def testKL(self):
mu1, sd1, mu2, sd2 = [np.random.rand(4, 6) for _ in range(4)]
pair_kl = pair_kl_divergence(mu1, sd1, mu2, sd2)
dist1 = distributions.Normal(mu1, sd1)
dist2 = distributions.Normal(mu2, sd2)
kl_tf = distributions.kl_divergence(dist1, dist2)
with tf.Session() as sess:
kl_val = sess.run(kl_tf)
kl_val = kl_val.sum(axis=-1)
self.assertAllClose(np.diag(pair_kl), kl_val)
def FC_bayes(x, shape, activation, scope, init=1e-3, bias=True):
"""
initializer for a fully-connected layer with tensorflow
inputs:
-shape, (tuple), input,output size of layer
-activation, (string), activation function to use
-init, (float), multiplier for random weight initialization
"""
with tf.variable_scope(scope):
if init == 'xavier':
init = np.sqrt(2.0 / (shape[0] + shape[1]))
factor = np.sqrt(2.0 / shape[0])
init = np.log(np.exp(factor) - 1)
W_mu = tf.Variable(tf.zeros(shape), name='W_mu')
W_sig = tf.Variable(tf.ones(shape) * init, name='W_sig')
W_sig = tf.log(1.0 + tf.exp(W_sig))
W_noise = tf.placeholder(shape=shape, dtype=tf.float32, name='W_eps')
b_mu = tf.Variable(tf.zeros([shape[1]]), name='b_mu')
b_sig = tf.Variable(tf.ones([shape[1]]) * init, name='b_sig')
b_sig = tf.log(1.0 + tf.exp(b_sig))
b_noise = tf.placeholder(shape=shape[1],
dtype=tf.float32,
name='b_eps')
W_samp = W_mu + W_sig * W_noise
b_samp = b_mu + b_sig * b_noise
#reg = tf.log(tf.reduce_prod(W_sig))+tf.log(tf.reduce_prod(b_sig))
Norm_w = distributions.Normal(loc=W_mu, scale=W_sig)
Norm_b = distributions.Normal(loc=b_mu, scale=b_sig)
N01_w = distributions.Normal(loc=tf.zeros(shape=shape),
scale=tf.ones(shape=shape) * factor)
N01_b = distributions.Normal(loc=tf.zeros(shape=shape[1]),
scale=tf.ones(shape=shape[1]) * factor)
reg = tf.reduce_sum(distributions.kl(Norm_w,N01_w)) +\
tf.reduce_sum(distributions.kl(Norm_b,N01_b))
if activation == 'relu':
activation = tf.nn.relu
elif activation == 'sigmoid':
activation = tf.nn.sigmoid
elif activation == 'tanh':
activation = tf.tanh
else:
activation = tf.identity
if bias:
h = tf.matmul(x, W_samp) + b_samp
else:
h = tf.matmul(x, W_samp)
a = activation(h)
return a, W_noise, b_noise, reg
def _build_model(self):
# input points
self.x = tf.placeholder(tf.float32, shape=[None, int(np.prod(self.x_dims))], name="X")
self.noise = tf.placeholder(tf.float32, shape=[None, self.z_dim], name="noise")
self.p_z = dbns.Normal(loc=tf.zeros_like(self.noise), scale=tf.ones_like(self.noise))
# encoder
z_params = self.encoder(self.x)
z_mu = z_params[:, self.z_dim:]
z_sigma = tf.exp(z_params[:, :self.z_dim])
self.q_z = dbns.Normal(loc=z_mu, scale=z_sigma)
# reparameterization trick
z = z_mu + tf.multiply(z_sigma, self.p_z.sample())
# z = self.q_z.sample()
# decoder
out_params = self.decoder(z)
mu = tf.nn.sigmoid(out_params[:, int(np.prod(self.x_dims)):]) # out_mu constrained to (0,1)
sigma = tf.exp(out_params[:, :int(np.prod(self.x_dims))])
self.x_hat = mu
self.p_x_z = dbns.Normal(loc=mu, scale=sigma)
nll_loss = -tf.reduce_sum(self.p_x_z.log_prob(self.x), 1)
kl_loss = 0.5 * tf.reduce_sum(tf.square(z_mu) + tf.square(z_sigma) - tf.log(1e-8 + tf.square(z_sigma)) - 1, 1)
# kl_loss = tf.reduce_sum(dbns.kl_divergence(self.q_z, self.p_z), 1)
self.loss = tf.reduce_mean(nll_loss + kl_loss)
self.elbo = -1.0 * tf.reduce_mean(nll_loss + kl_loss)
# in original paper, lr chosen from {0.01, 0.02, 0.1} depending on first few iters training performance
optimizer = tf.train.AdagradOptimizer(learning_rate=self.lr)
self.train_op = optimizer.minimize(self.loss)
# for sampling
self.z = self.encoder(self.x, trainable=False, reuse=True)
self.z_pl = tf.placeholder(tf.float32, shape=[None, self.z_dim])
self.sample = self.decoder(self.z_pl, trainable=False, reuse=True)
# tensorboard summaries
x_img = tf.reshape(self.x, [-1] + self.x_dims)
tf.summary.image('data', x_img)
xhat_img = tf.reshape(self.x_hat, [-1] + self.x_dims)
tf.summary.image('reconstruction', xhat_img)
tf.summary.scalar('reconstruction_loss', tf.reduce_mean(nll_loss))
tf.summary.scalar('kl_loss', tf.reduce_mean(kl_loss))
tf.summary.scalar('loss', self.loss)
tf.summary.scalar('elbo', self.elbo)
self.merged = tf.summary.merge_all()
def __init__(self,
n_steps,
cell,
step_success_prob,
where_mean=(-2., -2., 0., 0.),
where_std=(1., 1., 1., 1.),
disc_prior_type='geom',
rec_where_prior=False):
super().__init__()
self._n_steps = n_steps
self._cell = cell
self._init_disc_step_success_prob = step_success_prob
self._what_prior = tfd.Normal(0., 1.)
self._disc_prior_type = disc_prior_type
with self._enter_variable_scope():
if rec_where_prior:
init = list(where_mean) + list(where_std)
init = {'b': tf.constant_initializer(init)}
self._where_prior = RecurrentNormal(4,
128,
conditional=True,
output_initializers=init)
else:
self._where_prior = ConditionedNormalAdaptor(
where_mean, where_std)
def create_gmm_1(d,
K,
name='gmm',
reuse=False,
scale_act=tf.nn.softplus,
zero_mean=False,
ki=None):
with tf.variable_scope(name, reuse):
#tf.random_uniform_initializer(0.,3.)
probs = tf.nn.softmax(tf.get_variable('probs',
shape=[d, K],
dtype=DTYPE,
initializer=None),
axis=-1)
#tf.random_uniform_initializer(-.5,.5)
locs = tf.get_variable('locs',
shape=[d, K],
dtype=DTYPE,
initializer=None)
if zero_mean:
locs = tf.zeros_like(locs)
scales = tf.get_variable('scales',
shape=[d, K],
dtype=DTYPE,
initializer=None)
pis = tfd.Categorical(probs=probs)
ps = tfd.Normal(loc=locs, scale=scale_act(scales))
p = tf.contrib.distributions.MixtureSameFamily(pis, ps)
p = tf.contrib.distributions.Independent(p, 1)
return p
def call_gauss(self, inputs, input_stddev, training):
"""Pass a tensor through the bottleneck.
Args:
inputs: The tensor to be passed through the bottleneck.
training: Boolean. If `True`, returns a differentiable approximation of
the inputs, and their likelihoods under the modeled probability
densities. If `False`, returns the quantized inputs and their
likelihoods under the corresponding probability mass function. These
quantities can't be used for training, as they are not differentiable,
but represent actual compression more closely.
Returns:
values: `Tensor` with the same shape as `inputs` containing the perturbed
or quantized input values.
likelihood: `Tensor` with the same shape as `inputs` containing the
likelihood of `values` under the modeled probability distributions.
Raises:
ValueError: if `inputs` has different `dtype` or number of channels than
a previous set of inputs the model was invoked with earlier.
"""
inputs = ops.convert_to_tensor(inputs)
input_stddev = ops.convert_to_tensor(input_stddev)
inputs = array_ops.expand_dims(inputs, axis=4)
input_stddev = array_ops.expand_dims(input_stddev, axis=4)
#self.build_gauss(input_stddev)
half = constant_op.constant(.5, dtype=self.dtype)
# Convert to (channels, 1, batch) format by commuting channels to front
# and then collapsing.
values = inputs
stddev = input_stddev
# Add noise or quantize.
if training:
noise = random_ops.random_uniform(array_ops.shape(values), -half, half)
values = math_ops.add_n([values, noise])
elif self.optimize_integer_offset:
values = math_ops.round(values - self._medians) + self._medians
else:
values = math_ops.round(values)
mean = constant_op.constant(0., dtype=self.dtype, shape=(self.n, self.h, self.w, self.c, 1))
norm_dist = tfd.Normal(loc=mean, scale=stddev)
likelihood = abs(norm_dist.cdf(values + half) - norm_dist.cdf(values - half))
if self.likelihood_bound > 0:
likelihood_bound = constant_op.constant(
self.likelihood_bound, dtype=self.dtype)
likelihood = tfc_math_ops.lower_bound(likelihood, likelihood_bound)
if not context.executing_eagerly():
values_shape, likelihood_shape = self.compute_output_shape(inputs.shape)
values.set_shape(values_shape)
likelihood.set_shape(likelihood_shape)
values = array_ops.squeeze(values, [-1])
likelihood = array_ops.squeeze(likelihood, [-1])
return values, likelihood
def __init__(self, region, args, name,
given_means=None, given_stddevs=None, mean=0.0, num_dims=0):
super().__init__(name)
self.local_size = len(region)
self.args = args
self.scope = sorted(list(region))
self.size = args.num_gauss
self.num_dims = num_dims
self.np_means = None
self.means = self.args.param_provider.grab_leaf_parameters(
self.scope,
args.num_gauss,
name=name + "_means")
if args.gauss_min_var < args.gauss_max_var:
sigma_params = self.args.param_provider.grab_leaf_parameters(
self.scope,
args.num_gauss,
name=name + "_sigma_params")
self.sigma = args.gauss_min_var + (args.gauss_max_var - args.gauss_min_var) * tf.sigmoid(sigma_params)
else:
self.sigma = 1.0
self.dist = dists.Normal(self.means, tf.sqrt(self.sigma))
def __init__(self, series, time_step=10, batch_size=10, cell_size=100):
scale = np.std(np.multiply(series, 2.0), dtype=np.float32)
self.__nmFunc = dst.Normal(loc=np.mean(series, 0, np.float32),
scale=scale)
self.__meta_list = series
self.__input_size = 1
self.__output_size = 1
self.__forget_bias = 0.2
self.__batch_size = batch_size
self.__cell_size = cell_size
self.__time_step = time_step
self.cursor = 0
self.__labels = None
self.__batches = None
self.__input_layer_var = None
self.__cell_state = None
self.__out_state = None
self.__predication = None
self.__last_out = None
self.__input_placeholder = tf.placeholder(dtype=tf.float32,
name="Inputs")
self.__label_placeholder = tf.placeholder(dtype=tf.float32,
name="labels")
self.__predication = np.asarray([])
self.__generate_next_batch()
# Flags
self.trained = False
self.config = tf.ConfigProto(
device_count={"CPU": 3}, # limit to num_cpu_core CPU usage
inter_op_parallelism_threads=1,
intra_op_parallelism_threads=1,
log_device_placement=False)
self.__session_holder = None
def _build_network(self):
with tf.variable_scope('critic'):
c_h1 = layers.fully_connected(self.obs,
self.hidden_size,
trainable=self.trainable)
c_out = layers.fully_connected(c_h1,
1,
activation_fn=None,
trainable=self.trainable)
with tf.variable_scope('actor'):
a_h1 = layers.fully_connected(self.obs,
self.hidden_size,
trainable=self.trainable)
a_out = layers.fully_connected(a_h1,
self.num_ac,
activation_fn=None,
trainable=self.trainable)
log_std = tf.get_variable('log_std', [1, self.num_ac],
dtype=tf.float32,
initializer=tf.constant_initializer(
self.init_std),
trainable=self.trainable)
std = tf.exp(log_std)
a_dist = dist.Normal(a_out, std)
self.log_prob = a_dist.log_prob(self.acs)
self.entropy = tf.reduce_mean(a_dist.entropy())
self.value = tf.identity(c_out)
self.action = a_dist.sample()
def _compute_what(self, img, what_tm1, where, hidden_output,
temporal_hidden_state, temporal_state):
what_distrib = self._glimpse_encoder(img,
where,
mask_inpt=temporal_state)[0]
loc, scale = what_distrib.loc, what_distrib.scale
inpt = tf.concat((hidden_output, where, loc, scale), -1)
temporal_output, temporal_hidden_state = self._temporal_cell(
inpt, temporal_hidden_state)
n_dim = int(what_tm1.shape[-1])
temporal_distrib = GaussianFromParamVec(n_dim)(temporal_output)
remember_bias = {'b': tf.constant_initializer(1.)}
gates = Nonlinear(n_dim * 3, tf.nn.sigmoid,
remember_bias)(temporal_output)
gates *= .9999
forget_gate, input_gate, temporal_gate = tf.split(gates, 3, -1)
what_distrib = tfd.Normal(
loc=forget_gate * what_tm1 + (1. - input_gate) * loc +
(1. - temporal_gate) * temporal_distrib.loc,
scale=(1. - input_gate) * scale +
(1. - temporal_gate) * temporal_distrib.scale)
what_sample = what_distrib.sample()
what = what_sample
return what, what_sample, what_distrib.loc, what_distrib.scale, temporal_hidden_state
def __init__(self, config, attention, latent_space, scope='ChiSquaredSampler'):
""" Initialize the sampler """
super(ChiSquaredSampler, self).__init__(
config, attention, latent_space, scope=scope)
shape = (config.batch_size, self.sample_size)
self.prior = distributions.Normal(tf.zeros(shape), tf.ones(shape), name='prior')
def _compute_what(self, img, what_tm1, where, hidden_output, temporal_hidden_state, temporal_state):
# takes the input image, takes the glimpse based on the where latent variable
#and outputs the parameters for what distribution
what_distrib = self._glimpse_encoder(img, where, mask_inpt = temporal_state)[0]
#splitting the parameters into mean and covariance
loc, scale = what_distrib.loc, what_distrib.scale
#concatenating the output from ST(loc, scale) with output from relational RNN ant
#where latent variable from current timestep
inpt = tf.concat((hidden_output, where, loc, scale), -1)
#applying temporal RNN and getting the weights and hidden state
temporal_output, temporal_hidden_state = self._temporal_cell(inpt, temporal_hidden_state)
n_dim = int(what_tm1.shape[-1])
temporal_distrib = GaussianFromParamVec(n_dim)(temporal_output)
remember_bias = {'b': tf.constant_initializer(1.)}
gates = Nonlinear(n_dim * 3, tf.nn.sigmoid, remember_bias)(temporal_output)
gates *= .9999
forget_gate, input_gate, temporal_gate = tf.split(gates, 3, -1)
#constructing what distribution
what_distrib = tfd.Normal(
loc=forget_gate * what_tm1 + (1. - input_gate) * loc + (1. - temporal_gate) * temporal_distrib.loc,
scale=(1. - input_gate) * scale + (1. - temporal_gate) * temporal_distrib.scale
)
#sampling variable 'what'
what_sample = what_distrib.sample()
what = what_sample
return what, what_sample, what_distrib.loc, what_distrib.scale, temporal_hidden_state
class Experiment(object):
_noise = tfd.Normal(0., 0.001)
def __init__(self, env: gym.Env, use_monitor=False):
"""Experiment
Args:
env: OpenAI Gym.
use_monitor:
"""
self._env = env
self._use_monitor = use_monitor
self.episode_n = 0.
def rollout(self, policy, random_trajectory=False):
"""Return Normalized trajectry.
policy: Policy that returns probability.
Returns:
One trajectory.
"""
if not isinstance(self._env.action_space, gym.spaces.Box):
raise ValueError('This rollout is called only continuous ones.')
if len(self._env.action_space.shape) > 1:
raise NotImplementedError('Multi action cannot impemented.')
if not random_trajectory:
self.episode_n += 1
observ = self._env.reset()
if random_trajectory:
observ += self._noise.sample(sample_shape=observ.shape)
trajectory = []
for t in itertools.count():
action_prob = policy.predict(observ)
action = action_prob.sample()
assert action.shape == self._env.action_space.shape
next_observ, reward, done, _ = self._env.step(action)
trajectory.append(
transition(observ, action, next_observ, reward, done))
if done:
break
# Normalize observations.
observs, actions, next_observs, _, _ = map(np.asarray,
zip(*trajectory))
normalize_observ = np.stack([observs, next_observs], axis=0).mean()
normalize_action = actions.mean()
for i, t in enumerate(trajectory):
t = t._replace(
observ=(t.observ / normalize_observ),
action=(t.action / normalize_action),
next_observ=(t.next_observ / normalize_observ),
)
trajectory[i] = t
return trajectory
def loglikelihood(mean_arr, sampled_arr, sigma):
mu = tf.stack(mean_arr) # mu = [timesteps, batch_sz, loc_dim]
sampled = tf.stack(sampled_arr) # same shape as mu
gaussian = distributions.Normal(mu, sigma)
logll = gaussian.log_prob(sampled) # [timesteps, batch_sz, loc_dim]
logll = tf.reduce_sum(logll, 2)
logll = tf.transpose(logll) # [batch_sz, timesteps]
return logll
def get_mix(m, x, s, j, nn):
x1 = tf.Variable(x, name="x" + str(j) + str(nn))
# x1 = tf.constant(x, name="x" + str(j) + str(nn))
s1 = tf.Variable(s, name="s" + str(j) + str(nn))
m1 = tf.Variable(m, name="m" + str(j) + str(nn))
comp_1 = tfd.Normal(loc=x1, scale=s1)
return m1, comp_1
def _compute_where(self, hidden_output):
loc, scale = self._transform_estimator(hidden_output)
if self._where_loc_bias is not None:
loc += np.asarray(self._where_loc_bias).reshape((1, 4))
scale = tf.nn.softplus(scale) + 1e-2
where_distrib = tfd.Normal(loc, scale, validate_args=self._debug, allow_nan_stats=not self._debug)
return where_distrib.sample(), loc, scale
def define_model(self,
graph,
sample_size=20,
samples=1,
recognition=None,
reuse=None,
**kwargs):
"""
Define a VariationalAutoencoderModel.
For more details see Auto-Encoding Variational Bayes:
https://arxiv.org/pdf/1312.6114v10.pdf
Args:
sample_size: The size of the samples from the approximate posterior
samples: The number of samples approximate posterior
recognition: Model to generate q(z|x). Required parameter.
the model, but can be set later on the VariationalAutoencoderModel.
reuse: Whether to reuse variables
Returns:
A VariationalAutoencoderModel
"""
if recognition is None:
raise TypeError(
'define_model() needs keyword only argument recognition')
with tf.variable_scope('mean', reuse=reuse):
mean = self.linear_layers(recognition.output_tensor, (sample_size),
reuse=reuse)[-1]
with tf.variable_scope('log_variance', reuse=reuse):
log_variance = self.linear_layers(recognition.output_tensor,
(sample_size),
reuse=reuse)[-1]
p_z = distributions.Normal(0.0, 1.0, name='P_z')
q_z = distributions.Normal(mean,
tf.sqrt(tf.exp(log_variance)),
name='Q_z')
posterior = tf.reduce_mean(q_z.sample(samples), 0)
kl_divergence = tf.reduce_sum(distributions.kl(q_z, p_z), 1)
return VariationalAutoencoderModel(graph, recognition, posterior,
kl_divergence)
def get_data_normal_distribution_arguments():
try:
res = self.rm_dst
except:
mean = tf.reduce_mean(r1 + tf.multiply(gamma, r2))
scl = tf.sqrt(self.__get_variance(r1 + tf.multiply(gamma, r2)))
self.nm_dst = dst.Normal(loc=mean, scale=scl)
res = self.nm_dst
return res
def _z(self, arg, is_prior):
mean = self._linear(arg, self.z_size)
stddev = self._linear(arg, self.z_size)
stddev = tf.sqrt(tf.exp(stddev))
epsilon = tf.random_normal(shape=[self.batch_size, self.z_size])
z = mean if is_prior else mean + tf.multiply(stddev, epsilon)
pdf_z = ds.Normal(loc=mean, scale=stddev)
return z, pdf_z
def log_prob_of_improv(self, kernel, gp_sampled_x, gp_sampled_y, new_points):
mu = tf.reshape(self.mean(kernel, gp_sampled_x, gp_sampled_y, new_points), [-1])
sigma = tf.diag_part(self.cov(kernel, gp_sampled_x, new_points))
non_zero_variance = tf.greater(sigma, 0., name="variance_Control_Op")
sigma_safe = tf.where(non_zero_variance, sigma, tf.tile(tf.constant([1.]), tf.shape(sigma)))
normal_distribution = dist.Normal(loc=mu, scale=sigma_safe)
min_sampled_y = tf.reshape(tf.reduce_min(gp_sampled_y), [-1])
return tf.where(non_zero_variance,
normal_distribution.log_cdf(min_sampled_y),
tf.tile(tf.constant([0.]), tf.shape(non_zero_variance)))
def _build(self, what, where=None, presence=None):
glimpse = self._batch(self._glimpse_decoder)(what)
canvas = self._decode(glimpse, presence, where)
canvas, written_to_mask = self._add_mean_image(canvas, presence, where)
output_std = written_to_mask * self._output_std + (
1. - written_to_mask) * self._background_std
pdf = tfd.Normal(canvas, output_std)
return pdf, glimpse
def standard_normal(points, tfdt):
"""
Standard Normal
:param points:
:return:
"""
_loc = tf.constant(0.0, dtype=tfdt)
_scale = tf.constant(1.0, dtype=tfdt)
p = tfd.Normal(loc=_loc, scale=_scale)
return p.quantile(points)
def bayesian_categorical_crossentropy_internal(true, pred_var): std = K.sqrt(pred_var[:, num_classes:]) pred = pred_var[:, 0:num_classes] iterable = K.variable(np.ones(T)) dist = distributions.Normal(loc=K.zeros_like(std), scale=std) monte_carlo_results = K.map_fn(gaussian_categorical_crossentropy(true, pred, dist, num_classes), iterable, name='monte_carlo_results') variance_loss = K.mean(monte_carlo_results, axis=0) return variance_loss
def get_z(input, batch_size, z_size, W_mean, W_stddev, b_mean, b_stddev, is_prior):
mean = tf.tensordot(input, W_mean, axes=1) + b_mean
stddev = tf.tensordot(input, W_stddev, axes=1) + b_stddev
stddev = tf.sqrt(tf.exp(stddev))
epsilon = tf.random_normal(shape=[batch_size, z_size], name='epsilon')
z = mean if is_prior else mean + tf.multiply(stddev, epsilon)
pdf_z = ds.Normal(loc=mean, scale=stddev)
return z, pdf_z
def _forward(self, sample_m1, hidden_state, sample=None):
output, state = self._rnn(sample_m1, hidden_state)
stats = self._readout(output)
loc, scale = tf.split(stats, 2, -1)
scale = tf.nn.softplus(scale) + 1e-2
pdf = tfd.Normal(loc, scale)
if sample is None:
sample = pdf.sample()
return sample, loc, scale, pdf.log_prob(sample)
def gaussian_reparmeterization(logits_z, rnd_sample=None):
'''
The vanilla gaussian reparameterization from Kingma et. al
z = mu + sigma * N(0, I)
'''
zshp = logits_z.get_shape().as_list()
assert zshp[1] % 2 == 0
q_sigma = 1e-6 + tf.nn.softplus(logits_z[:, 0:zshp[1] / 2])
q_mu = logits_z[:, zshp[1] / 2:]
# Prior
p_z = d.Normal(loc=tf.zeros(zshp[1] / 2), scale=tf.ones(zshp[1] / 2))
with st.value_type(st.SampleValue()):
q_z = st.StochasticTensor(d.Normal(loc=q_mu, scale=q_sigma))
reduce_index = [1] if len(zshp) == 2 else [1, 2]
kl = d.kl(q_z.distribution, p_z, allow_nan_stats=False)
return [q_z, tf.reduce_sum(kl, reduce_index)]
