def set_model(self, model):
self.model = model
self.sess = K.get_session()
if self.histogram_freq and self.merged is None:
for layer in self.model.layers:
for weight in layer.weights:
mapped_weight_name = weight.name.replace(':', '_')
tf_summary.histogram(mapped_weight_name, weight)
if self.write_grads:
grads = model.optimizer.get_gradients(model.total_loss,
weight)
def is_indexed_slices(grad):
return type(grad).__name__ == 'IndexedSlices'
grads = [
grad.values if is_indexed_slices(grad) else grad
for grad in grads]
tf_summary.histogram(
'{}_grad'.format(mapped_weight_name), grads)
if self.write_images:
w_img = array_ops.squeeze(weight)
shape = K.int_shape(w_img)
if len(shape) == 2: # dense layer kernel case
if shape[0] > shape[1]:
w_img = array_ops.transpose(w_img)
shape = K.int_shape(w_img)
w_img = array_ops.reshape(w_img,
[1, shape[0], shape[1], 1])
elif len(shape) == 3: # convnet case
if K.image_data_format() == 'channels_last':
# switch to channels_first to display
# every kernel as a separate image
w_img = array_ops.transpose(w_img, perm=[2, 0, 1])
shape = K.int_shape(w_img)
w_img = array_ops.reshape(w_img,
[shape[0], shape[1], shape[2], 1])
elif len(shape) == 1: # bias case
w_img = array_ops.reshape(w_img, [1, shape[0], 1, 1])
else:
# not possible to handle 3D convnets etc.
continue
shape = K.int_shape(w_img)
assert len(shape) == 4 and shape[-1] in [1, 3, 4]
tf_summary.image(mapped_weight_name, w_img)
if hasattr(layer, 'output'):
tf_summary.histogram('{}_out'.format(layer.name),
layer.output)
self.merged = tf_summary.merge_all()
if self.write_graph:
self.writer = tf_summary.FileWriter(self.log_dir, self.sess.graph)
else:
self.writer = tf_summary.FileWriter(self.log_dir)
def sampling(args):
"""Reparameterization trick by sampling fr an isotropic unit Gaussian.
# Arguments:
args (tensor): mean and log of variance of Q(z|X)
# Returns:
z (tensor): sampled latent vector
"""
z_mean, z_log_var = args
batch = K.shape(z_mean)[0]
dim = K.int_shape(z_mean)[1]
# by default, random_normal has mean=0 and std=1.0
epsilon = K.random_normal(shape=(batch, dim))
return z_mean + K.exp(0.5 * z_log_var) * epsilon
def call(self, inputs, **kwargs):
input_shape = K.int_shape(inputs)
tensor_input_shape = K.shape(inputs)
# Prepare broadcasting shape.
reduction_axes = list(range(len(input_shape)))
del reduction_axes[self.axis]
broadcast_shape = [1] * len(input_shape)
broadcast_shape[self.axis] = input_shape[self.axis] // self.groups
broadcast_shape.insert(1, self.groups)
reshape_group_shape = K.shape(inputs)
group_axes = [reshape_group_shape[i] for i in range(len(input_shape))]
group_axes[self.axis] = input_shape[self.axis] // self.groups
group_axes.insert(1, self.groups)
# reshape inputs to new group shape
group_shape = [group_axes[0], self.groups] + group_axes[2:]
group_shape = K.stack(group_shape)
inputs = K.reshape(inputs, group_shape)
group_reduction_axes = list(range(len(group_axes)))
mean, variance = _moments(inputs,
group_reduction_axes[2:],
keep_dims=True)
inputs = (inputs - mean) / (K.sqrt(variance + self.epsilon))
# prepare broadcast shape
inputs = K.reshape(inputs, group_shape)
outputs = inputs
# In this case we must explicitly broadcast all parameters.
if self.scale:
broadcast_gamma = K.reshape(self.gamma, broadcast_shape)
outputs = outputs * broadcast_gamma
if self.center:
broadcast_beta = K.reshape(self.beta, broadcast_shape)
outputs = outputs + broadcast_beta
# finally we reshape the output back to the input shape
outputs = K.reshape(outputs, tensor_input_shape)
return outputs
def call(self, inputs, training=None):
input_shape = K.int_shape(inputs)
reduction_axes = list(range(0, len(input_shape)))
if (self.axis is not None):
del reduction_axes[self.axis]
del reduction_axes[0]
mean = K.mean(inputs, reduction_axes, keepdims=True)
stddev = K.std(inputs, reduction_axes, keepdims=True) + self.epsilon
normed = (inputs - mean) / stddev
broadcast_shape = [1] * len(input_shape)
if self.axis is not None:
broadcast_shape[self.axis] = input_shape[self.axis]
if self.scale:
broadcast_gamma = K.reshape(self.gamma, broadcast_shape)
normed = normed * broadcast_gamma
if self.center:
broadcast_beta = K.reshape(self.beta, broadcast_shape)
normed = normed + broadcast_beta
return normed
def call(self, x, mask=None):
if self.mode == 0 or self.mode == 2:
assert self.built, 'Layer must be built before being called'
input_shape = K.int_shape(x)
reduction_axes = list(range(len(input_shape)))
del reduction_axes[self.axis]
broadcast_shape = [1] * len(input_shape)
broadcast_shape[self.axis] = input_shape[self.axis]
mean_batch, var_batch = _moments(x,
reduction_axes,
shift=None,
keep_dims=False)
std_batch = (K.sqrt(var_batch + self.epsilon))
r_max_value = K.get_value(self.r_max)
r = std_batch / (K.sqrt(self.running_std + self.epsilon))
r = K.stop_gradient(K.clip(r, 1 / r_max_value, r_max_value))
d_max_value = K.get_value(self.d_max)
d = (mean_batch - self.running_mean) / K.sqrt(self.running_std +
self.epsilon)
d = K.stop_gradient(K.clip(d, -d_max_value, d_max_value))
if sorted(reduction_axes) == range(K.ndim(x))[:-1]:
x_normed_batch = (x - mean_batch) / std_batch
x_normed = (x_normed_batch * r + d) * self.gamma + self.beta
else:
# need broadcasting
broadcast_mean = K.reshape(mean_batch, broadcast_shape)
broadcast_std = K.reshape(std_batch, broadcast_shape)
broadcast_r = K.reshape(r, broadcast_shape)
broadcast_d = K.reshape(d, broadcast_shape)
broadcast_beta = K.reshape(self.beta, broadcast_shape)
broadcast_gamma = K.reshape(self.gamma, broadcast_shape)
x_normed_batch = (x - broadcast_mean) / broadcast_std
x_normed = (x_normed_batch * broadcast_r +
broadcast_d) * broadcast_gamma + broadcast_beta
# explicit update to moving mean and standard deviation
self.add_update([
K.moving_average_update(self.running_mean, mean_batch,
self.momentum),
K.moving_average_update(self.running_std, std_batch**2,
self.momentum)
], x)
# update r_max and d_max
r_val = self.r_max_value / (
1 + (self.r_max_value - 1) * K.exp(-self.t))
d_val = self.d_max_value / (1 + (
(self.d_max_value / 1e-3) - 1) * K.exp(-(2 * self.t)))
self.add_update([
K.update(self.r_max, r_val),
K.update(self.d_max, d_val),
K.update_add(self.t, K.variable(np.array([self.t_delta])))
], x)
if self.mode == 0:
if sorted(reduction_axes) == range(K.ndim(x))[:-1]:
x_normed_running = K.batch_normalization(
x,
self.running_mean,
self.running_std,
self.beta,
self.gamma,
epsilon=self.epsilon)
else:
# need broadcasting
broadcast_running_mean = K.reshape(self.running_mean,
broadcast_shape)
broadcast_running_std = K.reshape(self.running_std,
broadcast_shape)
broadcast_beta = K.reshape(self.beta, broadcast_shape)
broadcast_gamma = K.reshape(self.gamma, broadcast_shape)
x_normed_running = K.batch_normalization(
x,
broadcast_running_mean,
broadcast_running_std,
broadcast_beta,
broadcast_gamma,
epsilon=self.epsilon)
# pick the normalized form of x corresponding to the training phase
# for batch renormalization, inference time remains same as batchnorm
x_normed = K.in_train_phase(x_normed, x_normed_running)
elif self.mode == 1:
# sample-wise normalization
m = K.mean(x, axis=self.axis, keepdims=True)
std = K.sqrt(
K.var(x, axis=self.axis, keepdims=True) + self.epsilon)
x_normed_batch = (x - m) / (std + self.epsilon)
r_max_value = K.get_value(self.r_max)
r = std / (self.running_std + self.epsilon)
r = K.stop_gradient(K.clip(r, 1 / r_max_value, r_max_value))
d_max_value = K.get_value(self.d_max)
d = (m - self.running_mean) / (self.running_std + self.epsilon)
d = K.stop_gradient(K.clip(d, -d_max_value, d_max_value))
x_normed = ((x_normed_batch * r) + d) * self.gamma + self.beta
# update r_max and d_max
t_val = K.get_value(self.t)
r_val = self.r_max_value / (
1 + (self.r_max_value - 1) * np.exp(-t_val))
d_val = self.d_max_value / (1 + (
(self.d_max_value / 1e-3) - 1) * np.exp(-(2 * t_val)))
t_val += float(self.t_delta)
self.add_update([
K.update(self.r_max, r_val),
K.update(self.d_max, d_val),
K.update(self.t, t_val)
], x)
return x_normed
def __int_shape(self, x):
return KC.int_shape(x) if self.backend == 'tensorflow' else KC.shape(x)