def variational_bayes(h, n_code):
"""Summary
Parameters
----------
h : TYPE
Description
n_code : TYPE
Description
Returns
-------
name : TYPE
Description
"""
z_mu = tf.nn.tanh(utils.linear(h, n_code, name='mu')[0])
z_log_sigma = 0.5 * tf.nn.tanh(utils.linear(h, n_code, name='log_sigma')[0])
# Sample from noise distribution p(eps) ~ N(0, 1)
epsilon = tf.random_normal(tf.stack([tf.shape(h)[0], n_code]))
# Sample from posterior
z = tf.add(z_mu, tf.multiply(epsilon, tf.exp(z_log_sigma)), name='z')
# -log(p(z)/q(z|x)), bits by coding.
# variational bound coding costs kl(p(z|x)||q(z|x))
# d_kl(q(z|x)||p(z))
loss_z = -0.5 * tf.reduce_sum(1.0 + 2.0 * z_log_sigma - tf.square(z_mu) -
tf.exp(2.0 * z_log_sigma), 1)
return z, z_mu, z_log_sigma, loss_z
def variational_bayes(h, n_code):
"""Summary
Parameters
----------
h : TYPE
Description
n_code : TYPE
Description
Returns
-------
name : TYPE
Description
"""
z_mu = tf.nn.tanh(utils.linear(h, n_code, name='mu')[0])
z_log_sigma = 0.5 * tf.nn.tanh(
utils.linear(h, n_code, name='log_sigma')[0])
# Sample from noise distribution p(eps) ~ N(0, 1)
epsilon = tf.random_normal(tf.stack([tf.shape(h)[0], n_code]))
# Sample from posterior
z = tf.add(z_mu, tf.multiply(epsilon, tf.exp(z_log_sigma)), name='z')
# -log(p(z)/q(z|x)), bits by coding.
# variational bound coding costs kl(p(z|x)||q(z|x))
# d_kl(q(z|x)||p(z))
loss_z = -0.5 * tf.reduce_sum(
1.0 + 2.0 * z_log_sigma - tf.square(z_mu) - tf.exp(2.0 * z_log_sigma),
1)
return z, z_mu, z_log_sigma, loss_z
def discriminator(x,
convolutional=True,
filter_sizes=[5, 5, 5, 5],
activation=tf.nn.relu,
n_filters=[100, 100, 100, 100]):
"""Summary
Parameters
----------
x : TYPE
Description
convolutional : bool, optional
Description
filter_sizes : list, optional
Description
activation : TYPE, optional
Description
n_filters : list, optional
Description
Returns
-------
name : TYPE
Description
"""
encoding = encoder(
x=x,
convolutional=convolutional,
dimensions=n_filters,
filter_sizes=filter_sizes,
activation=activation)
# flatten, then linear to 1 value
res = utils.flatten(encoding['z'], name='flatten')
if res.get_shape().as_list()[-1] > 1:
res = utils.linear(res, 1)[0]
return {
'logits': res,
'probs': tf.nn.sigmoid(res),
'Ws': encoding['Ws'],
'hs': encoding['hs']
}
def discriminator(x,
convolutional=True,
filter_sizes=[5, 5, 5, 5],
activation=tf.nn.relu,
n_filters=[100, 100, 100, 100]):
"""Summary
Parameters
----------
x : TYPE
Description
convolutional : bool, optional
Description
filter_sizes : list, optional
Description
activation : TYPE, optional
Description
n_filters : list, optional
Description
Returns
-------
name : TYPE
Description
"""
encoding = encoder(
x=x,
convolutional=convolutional,
dimensions=n_filters,
filter_sizes=filter_sizes,
activation=activation)
# flatten, then linear to 1 value
res = utils.flatten(encoding['z'], name='flatten')
if res.get_shape().as_list()[-1] > 1:
res = utils.linear(res, 1)[0]
return {
'logits': res,
'probs': tf.nn.sigmoid(res),
'Ws': encoding['Ws'],
'hs': encoding['hs']
}
def encoder(x,
n_hidden=None,
dimensions=[],
filter_sizes=[],
convolutional=False,
activation=tf.nn.relu,
output_activation=tf.nn.sigmoid):
"""Summary
Parameters
----------
x : TYPE
Description
n_hidden : None, optional
Description
dimensions : list, optional
Description
filter_sizes : list, optional
Description
convolutional : bool, optional
Description
activation : TYPE, optional
Description
output_activation : TYPE, optional
Description
Returns
-------
name : TYPE
Description
"""
if convolutional:
x_tensor = utils.to_tensor(x)
else:
x_tensor = tf.reshape(tensor=x, shape=[-1, dimensions[0]])
dimensions = dimensions[1:]
current_input = x_tensor
Ws = []
hs = []
shapes = []
for layer_i, n_output in enumerate(dimensions):
with tf.variable_scope(str(layer_i)):
shapes.append(current_input.get_shape().as_list())
if convolutional:
h, W = utils.conv2d(x=current_input,
n_output=n_output,
k_h=filter_sizes[layer_i],
k_w=filter_sizes[layer_i],
padding='SAME')
else:
h, W = utils.linear(x=current_input, n_output=n_output)
h = activation(h)
Ws.append(W)
hs.append(h)
current_input = h
shapes.append(h.get_shape().as_list())
with tf.variable_scope('flatten'):
flattened = utils.flatten(current_input)
with tf.variable_scope('hidden'):
if n_hidden:
h, W = utils.linear(flattened, n_hidden, name='linear')
h = activation(h)
else:
h = flattened
return {'z': h, 'Ws': Ws, 'hs': hs, 'shapes': shapes}
def decoder(z,
shapes,
n_hidden=None,
dimensions=[],
filter_sizes=[],
convolutional=False,
activation=tf.nn.relu,
output_activation=tf.nn.relu):
"""Summary
Parameters
----------
z : TYPE
Description
shapes : TYPE
Description
n_hidden : None, optional
Description
dimensions : list, optional
Description
filter_sizes : list, optional
Description
convolutional : bool, optional
Description
activation : TYPE, optional
Description
output_activation : TYPE, optional
Description
Returns
-------
name : TYPE
Description
"""
with tf.variable_scope('hidden/1'):
if n_hidden:
h = utils.linear(z, n_hidden, name='linear')[0]
h = activation(h)
else:
h = z
with tf.variable_scope('hidden/2'):
dims = shapes[0]
size = dims[1] * dims[2] * dims[3] if convolutional else dims[1]
h = utils.linear(h, size, name='linear')[0]
current_input = activation(h)
if convolutional:
current_input = tf.reshape(
current_input,
tf.stack(
[tf.shape(current_input)[0], dims[1], dims[2], dims[3]]))
Ws = []
hs = []
for layer_i, n_output in enumerate(dimensions[1:]):
with tf.variable_scope('decoder/{}'.format(layer_i)):
if convolutional:
shape = shapes[layer_i + 1]
h, W = utils.deconv2d(x=current_input,
n_output_h=shape[1],
n_output_w=shape[2],
n_output_ch=shape[3],
n_input_ch=shapes[layer_i][3],
k_h=filter_sizes[layer_i],
k_w=filter_sizes[layer_i])
else:
h, W = utils.linear(x=current_input, n_output=n_output)
if (layer_i + 1) < len(dimensions):
h = activation(h)
else:
h = output_activation(h)
Ws.append(W)
hs.append(h)
current_input = h
z = tf.identity(current_input, name="x_tilde")
return {'x_tilde': current_input, 'Ws': Ws, 'hs': hs}
def VAE(input_shape=[None, 784],
n_filters=[64, 64, 64],
filter_sizes=[4, 4, 4],
n_hidden=32,
n_code=2,
activation=tf.nn.tanh,
dropout=False,
denoising=False,
convolutional=False,
variational=False):
"""(Variational) (Convolutional) (Denoising) Autoencoder.
Uses tied weights.
Parameters
----------
input_shape : list, optional
Shape of the input to the network. e.g. for MNIST: [None, 784].
n_filters : list, optional
Number of filters for each layer.
If convolutional=True, this refers to the total number of output
filters to create for each layer, with each layer's number of output
filters as a list.
If convolutional=False, then this refers to the total number of neurons
for each layer in a fully connected network.
filter_sizes : list, optional
Only applied when convolutional=True. This refers to the ksize (height
and width) of each convolutional layer.
n_hidden : int, optional
Only applied when variational=True. This refers to the first fully
connected layer prior to the variational embedding, directly after
the encoding. After the variational embedding, another fully connected
layer is created with the same size prior to decoding. Set to 0 to
not use an additional hidden layer.
n_code : int, optional
Only applied when variational=True. This refers to the number of
latent Gaussians to sample for creating the inner most encoding.
activation : function, optional
Activation function to apply to each layer, e.g. tf.nn.relu
dropout : bool, optional
Whether or not to apply dropout. If using dropout, you must feed a
value for 'keep_prob', as returned in the dictionary. 1.0 means no
dropout is used. 0.0 means every connection is dropped. Sensible
values are between 0.5-0.8.
denoising : bool, optional
Whether or not to apply denoising. If using denoising, you must feed a
value for 'corrupt_prob', as returned in the dictionary. 1.0 means no
corruption is used. 0.0 means every feature is corrupted. Sensible
values are between 0.5-0.8.
convolutional : bool, optional
Whether or not to use a convolutional network or else a fully connected
network will be created. This effects the n_filters parameter's
meaning.
variational : bool, optional
Whether or not to create a variational embedding layer. This will
create a fully connected layer after the encoding, if `n_hidden` is
greater than 0, then will create a multivariate gaussian sampling
layer, then another fully connected layer. The size of the fully
connected layers are determined by `n_hidden`, and the size of the
sampling layer is determined by `n_code`.
Returns
-------
model : dict
{
'cost': Tensor to optimize.
'Ws': All weights of the encoder.
'x': Input Placeholder
'z': Inner most encoding Tensor (latent features)
'y': Reconstruction of the Decoder
'keep_prob': Amount to keep when using Dropout
'corrupt_prob': Amount to corrupt when using Denoising
'train': Set to True when training/Applies to Batch Normalization.
}
"""
# network input / placeholders for train (bn) and dropout
x = tf.placeholder(tf.float32, input_shape, 'x')
phase_train = tf.placeholder(tf.bool, name='phase_train')
keep_prob = tf.placeholder(tf.float32, name='keep_prob')
corrupt_prob = tf.placeholder(tf.float32, [1])
if denoising:
current_input = utils.corrupt(x) * corrupt_prob + x * (1 - corrupt_prob)
# 2d -> 4d if convolution
x_tensor = utils.to_tensor(x) if convolutional else x
current_input = x_tensor
Ws = []
shapes = []
# Build the encoder
for layer_i, n_output in enumerate(n_filters):
with tf.variable_scope('encoder/{}'.format(layer_i)):
shapes.append(current_input.get_shape().as_list())
if convolutional:
h, W = utils.conv2d(
x=current_input,
n_output=n_output,
k_h=filter_sizes[layer_i],
k_w=filter_sizes[layer_i])
else:
h, W = utils.linear(x=current_input, n_output=n_output)
h = activation(batch_norm(h, phase_train, 'bn' + str(layer_i)))
if dropout:
h = tf.nn.dropout(h, keep_prob)
Ws.append(W)
current_input = h
shapes.append(current_input.get_shape().as_list())
with tf.variable_scope('variational'):
if variational:
dims = current_input.get_shape().as_list()
flattened = utils.flatten(current_input)
if n_hidden:
h = utils.linear(flattened, n_hidden, name='W_fc')[0]
h = activation(batch_norm(h, phase_train, 'fc/bn'))
if dropout:
h = tf.nn.dropout(h, keep_prob)
else:
h = flattened
z_mu = utils.linear(h, n_code, name='mu')[0]
z_log_sigma = 0.5 * utils.linear(h, n_code, name='log_sigma')[0]
# Sample from noise distribution p(eps) ~ N(0, 1)
epsilon = tf.random_normal(tf.stack([tf.shape(x)[0], n_code]))
# Sample from posterior
z = z_mu + tf.multiply(epsilon, tf.exp(z_log_sigma))
if n_hidden:
h = utils.linear(z, n_hidden, name='fc_t')[0]
h = activation(batch_norm(h, phase_train, 'fc_t/bn'))
if dropout:
h = tf.nn.dropout(h, keep_prob)
else:
h = z
size = dims[1] * dims[2] * dims[3] if convolutional else dims[1]
h = utils.linear(h, size, name='fc_t2')[0]
current_input = activation(batch_norm(h, phase_train, 'fc_t2/bn'))
if dropout:
current_input = tf.nn.dropout(current_input, keep_prob)
if convolutional:
current_input = tf.reshape(current_input,
tf.stack([
tf.shape(current_input)[0],
dims[1], dims[2], dims[3]
]))
else:
z = current_input
shapes.reverse()
n_filters.reverse()
Ws.reverse()
n_filters += [input_shape[-1]]
# %%
# Decoding layers
for layer_i, n_output in enumerate(n_filters[1:]):
with tf.variable_scope('decoder/{}'.format(layer_i)):
shape = shapes[layer_i + 1]
if convolutional:
h, W = utils.deconv2d(
x=current_input,
n_output_h=shape[1],
n_output_w=shape[2],
n_output_ch=shape[3],
n_input_ch=shapes[layer_i][3],
k_h=filter_sizes[layer_i],
k_w=filter_sizes[layer_i])
else:
h, W = utils.linear(x=current_input, n_output=n_output)
h = activation(batch_norm(h, phase_train, 'dec/bn' + str(layer_i)))
if dropout:
h = tf.nn.dropout(h, keep_prob)
current_input = h
y = current_input
x_flat = utils.flatten(x)
y_flat = utils.flatten(y)
# l2 loss
loss_x = tf.reduce_sum(tf.squared_difference(x_flat, y_flat), 1)
if variational:
# variational lower bound, kl-divergence
loss_z = -0.5 * tf.reduce_sum(1.0 + 2.0 * z_log_sigma - tf.square(z_mu)
- tf.exp(2.0 * z_log_sigma), 1)
# add l2 loss
cost = tf.reduce_mean(loss_x + loss_z)
else:
# just optimize l2 loss
cost = tf.reduce_mean(loss_x)
return {
'cost': cost,
'Ws': Ws,
'x': x,
'z': z,
'y': y,
'keep_prob': keep_prob,
'corrupt_prob': corrupt_prob,
'train': phase_train
}
def VAE(input_shape=[None, 784],
n_filters=[64, 64, 64],
filter_sizes=[4, 4, 4],
n_hidden=32,
n_code=2,
activation=tf.nn.tanh,
dropout=False,
denoising=False,
convolutional=False,
variational=False):
"""(Variational) (Convolutional) (Denoising) Autoencoder.
Uses tied weights.
Parameters
----------
input_shape : list, optional
Shape of the input to the network. e.g. for MNIST: [None, 784].
n_filters : list, optional
Number of filters for each layer.
If convolutional=True, this refers to the total number of output
filters to create for each layer, with each layer's number of output
filters as a list.
If convolutional=False, then this refers to the total number of neurons
for each layer in a fully connected network.
filter_sizes : list, optional
Only applied when convolutional=True. This refers to the ksize (height
and width) of each convolutional layer.
n_hidden : int, optional
Only applied when variational=True. This refers to the first fully
connected layer prior to the variational embedding, directly after
the encoding. After the variational embedding, another fully connected
layer is created with the same size prior to decoding. Set to 0 to
not use an additional hidden layer.
n_code : int, optional
Only applied when variational=True. This refers to the number of
latent Gaussians to sample for creating the inner most encoding.
activation : function, optional
Activation function to apply to each layer, e.g. tf.nn.relu
dropout : bool, optional
Whether or not to apply dropout. If using dropout, you must feed a
value for 'keep_prob', as returned in the dictionary. 1.0 means no
dropout is used. 0.0 means every connection is dropped. Sensible
values are between 0.5-0.8.
denoising : bool, optional
Whether or not to apply denoising. If using denoising, you must feed a
value for 'corrupt_prob', as returned in the dictionary. 1.0 means no
corruption is used. 0.0 means every feature is corrupted. Sensible
values are between 0.5-0.8.
convolutional : bool, optional
Whether or not to use a convolutional network or else a fully connected
network will be created. This effects the n_filters parameter's
meaning.
variational : bool, optional
Whether or not to create a variational embedding layer. This will
create a fully connected layer after the encoding, if `n_hidden` is
greater than 0, then will create a multivariate gaussian sampling
layer, then another fully connected layer. The size of the fully
connected layers are determined by `n_hidden`, and the size of the
sampling layer is determined by `n_code`.
Returns
-------
model : dict
{
'cost': Tensor to optimize.
'Ws': All weights of the encoder.
'x': Input Placeholder
'z': Inner most encoding Tensor (latent features)
'y': Reconstruction of the Decoder
'keep_prob': Amount to keep when using Dropout
'corrupt_prob': Amount to corrupt when using Denoising
'train': Set to True when training/Applies to Batch Normalization.
}
"""
# network input / placeholders for train (bn) and dropout
x = tf.placeholder(tf.float32, input_shape, 'x')
phase_train = tf.placeholder(tf.bool, name='phase_train')
keep_prob = tf.placeholder(tf.float32, name='keep_prob')
corrupt_prob = tf.placeholder(tf.float32, [1])
if denoising:
current_input = utils.corrupt(x) * corrupt_prob + x * (1 -
corrupt_prob)
# 2d -> 4d if convolution
x_tensor = utils.to_tensor(x) if convolutional else x
current_input = x_tensor
Ws = []
shapes = []
# Build the encoder
for layer_i, n_output in enumerate(n_filters):
with tf.variable_scope('encoder/{}'.format(layer_i)):
shapes.append(current_input.get_shape().as_list())
if convolutional:
h, W = utils.conv2d(x=current_input,
n_output=n_output,
k_h=filter_sizes[layer_i],
k_w=filter_sizes[layer_i])
else:
h, W = utils.linear(x=current_input, n_output=n_output)
h = activation(batch_norm(h, phase_train, 'bn' + str(layer_i)))
if dropout:
h = tf.nn.dropout(h, keep_prob)
Ws.append(W)
current_input = h
shapes.append(current_input.get_shape().as_list())
with tf.variable_scope('variational'):
if variational:
dims = current_input.get_shape().as_list()
flattened = utils.flatten(current_input)
if n_hidden:
h = utils.linear(flattened, n_hidden, name='W_fc')[0]
h = activation(batch_norm(h, phase_train, 'fc/bn'))
if dropout:
h = tf.nn.dropout(h, keep_prob)
else:
h = flattened
z_mu = utils.linear(h, n_code, name='mu')[0]
z_log_sigma = 0.5 * utils.linear(h, n_code, name='log_sigma')[0]
# Sample from noise distribution p(eps) ~ N(0, 1)
epsilon = tf.random_normal(tf.stack([tf.shape(x)[0], n_code]))
# Sample from posterior
z = z_mu + tf.multiply(epsilon, tf.exp(z_log_sigma))
if n_hidden:
h = utils.linear(z, n_hidden, name='fc_t')[0]
h = activation(batch_norm(h, phase_train, 'fc_t/bn'))
if dropout:
h = tf.nn.dropout(h, keep_prob)
else:
h = z
size = dims[1] * dims[2] * dims[3] if convolutional else dims[1]
h = utils.linear(h, size, name='fc_t2')[0]
current_input = activation(batch_norm(h, phase_train, 'fc_t2/bn'))
if dropout:
current_input = tf.nn.dropout(current_input, keep_prob)
if convolutional:
current_input = tf.reshape(
current_input,
tf.stack([
tf.shape(current_input)[0], dims[1], dims[2], dims[3]
]))
else:
z = current_input
shapes.reverse()
n_filters.reverse()
Ws.reverse()
n_filters += [input_shape[-1]]
# %%
# Decoding layers
for layer_i, n_output in enumerate(n_filters[1:]):
with tf.variable_scope('decoder/{}'.format(layer_i)):
shape = shapes[layer_i + 1]
if convolutional:
h, W = utils.deconv2d(x=current_input,
n_output_h=shape[1],
n_output_w=shape[2],
n_output_ch=shape[3],
n_input_ch=shapes[layer_i][3],
k_h=filter_sizes[layer_i],
k_w=filter_sizes[layer_i])
else:
h, W = utils.linear(x=current_input, n_output=n_output)
h = activation(batch_norm(h, phase_train, 'dec/bn' + str(layer_i)))
if dropout:
h = tf.nn.dropout(h, keep_prob)
current_input = h
y = current_input
x_flat = utils.flatten(x)
y_flat = utils.flatten(y)
# l2 loss
loss_x = tf.reduce_sum(tf.squared_difference(x_flat, y_flat), 1)
if variational:
# variational lower bound, kl-divergence
loss_z = -0.5 * tf.reduce_sum(
1.0 + 2.0 * z_log_sigma - tf.square(z_mu) -
tf.exp(2.0 * z_log_sigma), 1)
# add l2 loss
cost = tf.reduce_mean(loss_x + loss_z)
else:
# just optimize l2 loss
cost = tf.reduce_mean(loss_x)
return {
'cost': cost,
'Ws': Ws,
'x': x,
'z': z,
'y': y,
'keep_prob': keep_prob,
'corrupt_prob': corrupt_prob,
'train': phase_train
}
def decoder(z,
dimensions=[],
channels=[],
filter_sizes=[],
convolutional=False,
activation=tf.nn.relu,
output_activation=tf.nn.tanh,
reuse=None):
"""Decoder network codes input `x` to layers defined by dimensions.
In contrast with `encoder`, this requires information on the number of
output channels in each layer for convolution. Otherwise, it is mostly
the same.
Parameters
----------
z : tf.Tensor
Input to the decoder network, e.g. tf.Placeholder or tf.Variable
dimensions : list, optional
List of the number of neurons in each layer (convolutional=False) -or-
List of the number of filters in each layer (convolutional=True), e.g.
[100, 100, 100, 100] for a 4-layer deep network with 100 in each layer.
channels : list, optional
For decoding when convolutional=True, require the number of output
channels in each layer.
filter_sizes : list, optional
List of the size of the kernel in each layer, e.g.:
[3, 3, 3, 3] is a 4-layer deep network w/ 3 x 3 kernels in every layer.
convolutional : bool, optional
Whether or not to use convolutional layers.
activation : fn, optional
Function for applying an activation, e.g. tf.nn.relu
output_activation : fn, optional
Function for applying an activation on the last layer, e.g. tf.nn.relu
reuse : bool, optional
For each layer's variable scope, whether to reuse existing variables.
Returns
-------
h : tf.Tensor
Output tensor of the decoder
"""
if convolutional:
with tf.variable_scope('fc', reuse=reuse):
z1, W = utils.linear(
x=z,
n_output=channels[0] * dimensions[0][0] * dimensions[0][1],
reuse=reuse)
rsz = tf.reshape(
z1, [-1, dimensions[0][0], dimensions[0][1], channels[0]])
current_input = activation(rsz)
dimensions = dimensions[1:]
channels = channels[1:]
filter_sizes = filter_sizes[1:]
else:
current_input = z
for layer_i, n_output in enumerate(dimensions):
with tf.variable_scope(str(layer_i), reuse=reuse):
if convolutional:
h, W = utils.deconv2d(
x=current_input,
n_output_h=n_output[0],
n_output_w=n_output[1],
n_output_ch=channels[layer_i],
k_h=filter_sizes[layer_i],
k_w=filter_sizes[layer_i],
padding='SAME',
reuse=reuse)
else:
h, W = utils.linear(
x=current_input, n_output=n_output, reuse=reuse)
if layer_i < len(dimensions) - 1:
output = activation(h)
else:
output = h
current_input = output
if output_activation is None:
return current_input
else:
return output_activation(current_input)
def encoder(x,
dimensions=[],
filter_sizes=[],
convolutional=False,
activation=tf.nn.relu,
output_activation=tf.nn.sigmoid,
reuse=False):
"""Encoder network codes input `x` to layers defined by dimensions.
Parameters
----------
x : tf.Tensor
Input to the encoder network, e.g. tf.Placeholder or tf.Variable
dimensions : list, optional
List of the number of neurons in each layer (convolutional=False) -or-
List of the number of filters in each layer (convolutional=True), e.g.
[100, 100, 100, 100] for a 4-layer deep network with 100 in each layer.
filter_sizes : list, optional
List of the size of the kernel in each layer, e.g.:
[3, 3, 3, 3] is a 4-layer deep network w/ 3 x 3 kernels in every layer.
convolutional : bool, optional
Whether or not to use convolutional layers.
activation : fn, optional
Function for applying an activation, e.g. tf.nn.relu
output_activation : fn, optional
Function for applying an activation on the last layer, e.g. tf.nn.relu
reuse : bool, optional
For each layer's variable scope, whether to reuse existing variables.
Returns
-------
h : tf.Tensor
Output tensor of the encoder
"""
# %%
# ensure 2-d is converted to square tensor.
if convolutional:
x_tensor = utils.to_tensor(x)
else:
x_tensor = tf.reshape(tensor=x, shape=[-1, dimensions[0]])
dimensions = dimensions[1:]
current_input = x_tensor
for layer_i, n_output in enumerate(dimensions):
with tf.variable_scope(str(layer_i), reuse=reuse):
if convolutional:
h, W = utils.conv2d(
x=current_input,
n_output=n_output,
k_h=filter_sizes[layer_i],
k_w=filter_sizes[layer_i],
padding='SAME',
reuse=reuse)
else:
h, W = utils.linear(
x=current_input, n_output=n_output, reuse=reuse)
output = activation(h)
current_input = output
flattened = utils.flatten(current_input, name='flatten', reuse=reuse)
if output_activation is None:
return flattened
else:
return output_activation(flattened)
def decoder(z,
dimensions=[],
channels=[],
filter_sizes=[],
convolutional=False,
activation=tf.nn.relu,
output_activation=tf.nn.tanh,
reuse=None):
"""Decoder network codes input `x` to layers defined by dimensions.
In contrast with `encoder`, this requires information on the number of
output channels in each layer for convolution. Otherwise, it is mostly
the same.
Parameters
----------
z : tf.Tensor
Input to the decoder network, e.g. tf.Placeholder or tf.Variable
dimensions : list, optional
List of the number of neurons in each layer (convolutional=False) -or-
List of the number of filters in each layer (convolutional=True), e.g.
[100, 100, 100, 100] for a 4-layer deep network with 100 in each layer.
channels : list, optional
For decoding when convolutional=True, require the number of output
channels in each layer.
filter_sizes : list, optional
List of the size of the kernel in each layer, e.g.:
[3, 3, 3, 3] is a 4-layer deep network w/ 3 x 3 kernels in every layer.
convolutional : bool, optional
Whether or not to use convolutional layers.
activation : fn, optional
Function for applying an activation, e.g. tf.nn.relu
output_activation : fn, optional
Function for applying an activation on the last layer, e.g. tf.nn.relu
reuse : bool, optional
For each layer's variable scope, whether to reuse existing variables.
Returns
-------
h : tf.Tensor
Output tensor of the decoder
"""
if convolutional:
with tf.variable_scope('fc', reuse=reuse):
z1, W = utils.linear(x=z,
n_output=channels[0] * dimensions[0][0] *
dimensions[0][1],
reuse=reuse)
rsz = tf.reshape(
z1, [-1, dimensions[0][0], dimensions[0][1], channels[0]])
current_input = activation(rsz)
dimensions = dimensions[1:]
channels = channels[1:]
filter_sizes = filter_sizes[1:]
else:
current_input = z
for layer_i, n_output in enumerate(dimensions):
with tf.variable_scope(str(layer_i), reuse=reuse):
if convolutional:
h, W = utils.deconv2d(x=current_input,
n_output_h=n_output[0],
n_output_w=n_output[1],
n_output_ch=channels[layer_i],
k_h=filter_sizes[layer_i],
k_w=filter_sizes[layer_i],
padding='SAME',
reuse=reuse)
else:
h, W = utils.linear(x=current_input,
n_output=n_output,
reuse=reuse)
if layer_i < len(dimensions) - 1:
output = activation(h)
else:
output = h
current_input = output
if output_activation is None:
return current_input
else:
return output_activation(current_input)
def encoder(x,
dimensions=[],
filter_sizes=[],
convolutional=False,
activation=tf.nn.relu,
output_activation=tf.nn.sigmoid,
reuse=False):
"""Encoder network codes input `x` to layers defined by dimensions.
Parameters
----------
x : tf.Tensor
Input to the encoder network, e.g. tf.Placeholder or tf.Variable
dimensions : list, optional
List of the number of neurons in each layer (convolutional=False) -or-
List of the number of filters in each layer (convolutional=True), e.g.
[100, 100, 100, 100] for a 4-layer deep network with 100 in each layer.
filter_sizes : list, optional
List of the size of the kernel in each layer, e.g.:
[3, 3, 3, 3] is a 4-layer deep network w/ 3 x 3 kernels in every layer.
convolutional : bool, optional
Whether or not to use convolutional layers.
activation : fn, optional
Function for applying an activation, e.g. tf.nn.relu
output_activation : fn, optional
Function for applying an activation on the last layer, e.g. tf.nn.relu
reuse : bool, optional
For each layer's variable scope, whether to reuse existing variables.
Returns
-------
h : tf.Tensor
Output tensor of the encoder
"""
# %%
# ensure 2-d is converted to square tensor.
if convolutional:
x_tensor = utils.to_tensor(x)
else:
x_tensor = tf.reshape(tensor=x, shape=[-1, dimensions[0]])
dimensions = dimensions[1:]
current_input = x_tensor
for layer_i, n_output in enumerate(dimensions):
with tf.variable_scope(str(layer_i), reuse=reuse):
if convolutional:
h, W = utils.conv2d(x=current_input,
n_output=n_output,
k_h=filter_sizes[layer_i],
k_w=filter_sizes[layer_i],
padding='SAME',
reuse=reuse)
else:
h, W = utils.linear(x=current_input,
n_output=n_output,
reuse=reuse)
output = activation(h)
current_input = output
flattened = utils.flatten(current_input, name='flatten', reuse=reuse)
if output_activation is None:
return flattened
else:
return output_activation(flattened)
def encoder(x,
n_hidden=None,
dimensions=[],
filter_sizes=[],
convolutional=False,
activation=tf.nn.relu,
output_activation=tf.nn.sigmoid):
"""Summary
Parameters
----------
x : TYPE
Description
n_hidden : None, optional
Description
dimensions : list, optional
Description
filter_sizes : list, optional
Description
convolutional : bool, optional
Description
activation : TYPE, optional
Description
output_activation : TYPE, optional
Description
Returns
-------
name : TYPE
Description
"""
if convolutional:
x_tensor = utils.to_tensor(x)
else:
x_tensor = tf.reshape(tensor=x, shape=[-1, dimensions[0]])
dimensions = dimensions[1:]
current_input = x_tensor
Ws = []
hs = []
shapes = []
for layer_i, n_output in enumerate(dimensions):
with tf.variable_scope(str(layer_i)):
shapes.append(current_input.get_shape().as_list())
if convolutional:
h, W = utils.conv2d(
x=current_input,
n_output=n_output,
k_h=filter_sizes[layer_i],
k_w=filter_sizes[layer_i],
padding='SAME')
else:
h, W = utils.linear(x=current_input, n_output=n_output)
h = activation(h)
Ws.append(W)
hs.append(h)
current_input = h
shapes.append(h.get_shape().as_list())
with tf.variable_scope('flatten'):
flattened = utils.flatten(current_input)
with tf.variable_scope('hidden'):
if n_hidden:
h, W = utils.linear(flattened, n_hidden, name='linear')
h = activation(h)
else:
h = flattened
return {'z': h, 'Ws': Ws, 'hs': hs, 'shapes': shapes}
def decoder(z,
shapes,
n_hidden=None,
dimensions=[],
filter_sizes=[],
convolutional=False,
activation=tf.nn.relu,
output_activation=tf.nn.relu):
"""Summary
Parameters
----------
z : TYPE
Description
shapes : TYPE
Description
n_hidden : None, optional
Description
dimensions : list, optional
Description
filter_sizes : list, optional
Description
convolutional : bool, optional
Description
activation : TYPE, optional
Description
output_activation : TYPE, optional
Description
Returns
-------
name : TYPE
Description
"""
with tf.variable_scope('hidden/1'):
if n_hidden:
h = utils.linear(z, n_hidden, name='linear')[0]
h = activation(h)
else:
h = z
with tf.variable_scope('hidden/2'):
dims = shapes[0]
size = dims[1] * dims[2] * dims[3] if convolutional else dims[1]
h = utils.linear(h, size, name='linear')[0]
current_input = activation(h)
if convolutional:
current_input = tf.reshape(
current_input,
tf.stack(
[tf.shape(current_input)[0], dims[1], dims[2], dims[3]]))
Ws = []
hs = []
for layer_i, n_output in enumerate(dimensions[1:]):
with tf.variable_scope('decoder/{}'.format(layer_i)):
if convolutional:
shape = shapes[layer_i + 1]
h, W = utils.deconv2d(
x=current_input,
n_output_h=shape[1],
n_output_w=shape[2],
n_output_ch=shape[3],
n_input_ch=shapes[layer_i][3],
k_h=filter_sizes[layer_i],
k_w=filter_sizes[layer_i])
else:
h, W = utils.linear(x=current_input, n_output=n_output)
if (layer_i + 1) < len(dimensions):
h = activation(h)
else:
h = output_activation(h)
Ws.append(W)
hs.append(h)
current_input = h
z = tf.identity(current_input, name="x_tilde")
return {'x_tilde': current_input, 'Ws': Ws, 'hs': hs}