INSTRUCTION
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Linearly interpolate between two tensors at coeff.
Args:
tensor1: 4-D Tensor, shape=(NHWC)
tensor2: 4-D Tensor, shape=(NHWC)
coeffs: list of floats.
Returns:
interp_latents: 5-D Tensor, with interp_latents[i] representing
interpolations at coeffs[i].
shape=(len(coeffs), NHWC) | def linear_interpolate(tensor1, tensor2, coeffs):
"""Linearly interpolate between two tensors at coeff.
Args:
tensor1: 4-D Tensor, shape=(NHWC)
tensor2: 4-D Tensor, shape=(NHWC)
coeffs: list of floats.
Returns:
interp_latents: 5-D Tensor, with interp_latents[i] representing
interpolations at coeffs[i].
shape=(len(coeffs), NHWC)
"""
interp_tensors = []
for coeff in coeffs:
interp_tensor = tensor1 + coeff * (tensor2 - tensor1)
interp_tensors.append(interp_tensor)
return tf.concat(interp_tensors, axis=0) |
Linearly interpolate channel at "rank" between two tensors.
The channels are ranked according to their L2 norm between tensor1[channel]
and tensor2[channel].
Args:
tensor1: 4-D Tensor, NHWC
tensor2: 4-D Tensor, NHWC
coeffs: list of floats.
rank: integer.
Returns:
interp_latents: list of interpolated 4-D Tensors, shape=(NHWC) | def linear_interpolate_rank(tensor1, tensor2, coeffs, rank=1):
"""Linearly interpolate channel at "rank" between two tensors.
The channels are ranked according to their L2 norm between tensor1[channel]
and tensor2[channel].
Args:
tensor1: 4-D Tensor, NHWC
tensor2: 4-D Tensor, NHWC
coeffs: list of floats.
rank: integer.
Returns:
interp_latents: list of interpolated 4-D Tensors, shape=(NHWC)
"""
# sum across space, max across channels.
_, _, _, num_channels = common_layers.shape_list(tensor1)
diff_sq_sum = tf.reduce_sum((tensor1 - tensor2)**2, axis=(0, 1, 2))
_, feature_ranks = tf.math.top_k(diff_sq_sum, k=rank)
feature_rank = feature_ranks[-1]
channel_inds = tf.range(num_channels, dtype=tf.int32)
channel_mask = tf.equal(channel_inds, feature_rank)
ones_t = tf.ones(num_channels, dtype=tf.float32)
zeros_t = tf.zeros(num_channels, dtype=tf.float32)
interp_tensors = []
for coeff in coeffs:
curr_coeff = tf.where(channel_mask, coeff * ones_t, zeros_t)
interp_tensor = tensor1 + curr_coeff * (tensor2 - tensor1)
interp_tensors.append(interp_tensor)
return tf.concat(interp_tensors, axis=0) |
Converts x from [-0.5, 0.5], to [0, 255].
Args:
x: 3-D or 4-D Tensor normalized between [-0.5, 0.5]
n_bits_x: Number of bits representing each pixel of the output.
Defaults to 8, to default to 256 possible values.
Returns:
x: 3-D or 4-D Tensor representing images or videos. | def postprocess(x, n_bits_x=8):
"""Converts x from [-0.5, 0.5], to [0, 255].
Args:
x: 3-D or 4-D Tensor normalized between [-0.5, 0.5]
n_bits_x: Number of bits representing each pixel of the output.
Defaults to 8, to default to 256 possible values.
Returns:
x: 3-D or 4-D Tensor representing images or videos.
"""
x = tf.where(tf.is_finite(x), x, tf.ones_like(x))
x = tf.clip_by_value(x, -0.5, 0.5)
x += 0.5
x = x * 2**n_bits_x
return tf.cast(tf.clip_by_value(x, 0, 255), dtype=tf.uint8) |
Returns a single or list of conditional latents at level 'level'. | def get_cond_latents_at_level(cond_latents, level, hparams):
"""Returns a single or list of conditional latents at level 'level'."""
if cond_latents:
if hparams.latent_dist_encoder in ["conv_net", "conv3d_net"]:
return [cond_latent[level] for cond_latent in cond_latents]
elif hparams.latent_dist_encoder in ["pointwise", "conv_lstm"]:
return cond_latents[level] |
Shape checking for cond_latents. | def check_cond_latents(cond_latents, hparams):
"""Shape checking for cond_latents."""
if cond_latents is None:
return
if not isinstance(cond_latents[0], list):
cond_latents = [cond_latents]
exp_num_latents = hparams.num_cond_latents
if hparams.latent_dist_encoder == "conv_net":
exp_num_latents += int(hparams.cond_first_frame)
if len(cond_latents) != exp_num_latents:
raise ValueError("Expected number of cond_latents: %d, got %d" %
(exp_num_latents, len(cond_latents)))
for cond_latent in cond_latents:
if len(cond_latent) != hparams.n_levels - 1:
raise ValueError("Expected level_latents to be %d, got %d" %
(hparams.n_levels - 1, len(cond_latent))) |
Wrapper for data-dependent initialization. | def get_variable_ddi(name, shape, initial_value, dtype=tf.float32, init=False,
trainable=True):
"""Wrapper for data-dependent initialization."""
# If init is a tf bool: w is assigned dynamically at runtime.
# If init is a python bool: then w is determined during graph construction.
w = tf.get_variable(name, shape, dtype, None, trainable=trainable)
if isinstance(init, bool):
if init:
return assign(w, initial_value)
return w
else:
return tf.cond(init, lambda: assign(w, initial_value), lambda: w) |
Dropout x with dropout_rate = rate.
Apply zero dropout during init or prediction time.
Args:
x: 4-D Tensor, shape=(NHWC).
rate: Dropout rate.
init: Initialization.
Returns:
x: activations after dropout. | def get_dropout(x, rate=0.0, init=True):
"""Dropout x with dropout_rate = rate.
Apply zero dropout during init or prediction time.
Args:
x: 4-D Tensor, shape=(NHWC).
rate: Dropout rate.
init: Initialization.
Returns:
x: activations after dropout.
"""
if init or rate == 0:
return x
return tf.layers.dropout(x, rate=rate, training=True) |
Applies actnorm to each time-step independently.
There are a total of 2*n_channels*n_steps parameters learnt.
Args:
name: variable scope.
x: 5-D Tensor, (NTHWC)
logscale_factor: Increases the learning rate of the scale by
logscale_factor.
Returns:
x: 5-D Tensor, (NTHWC) with the per-timestep, per-channel normalization. | def actnorm_3d(name, x, logscale_factor=3.):
"""Applies actnorm to each time-step independently.
There are a total of 2*n_channels*n_steps parameters learnt.
Args:
name: variable scope.
x: 5-D Tensor, (NTHWC)
logscale_factor: Increases the learning rate of the scale by
logscale_factor.
Returns:
x: 5-D Tensor, (NTHWC) with the per-timestep, per-channel normalization.
"""
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
x = tf.unstack(x, axis=1)
x_normed = []
for ind, x_step in enumerate(x):
x_step, _ = actnorm("actnorm_%d" % ind, x_step,
logscale_factor=logscale_factor)
x_normed.append(x_step)
return tf.stack(x_normed, axis=1), None |
x_{ij} = s x x_{ij} + b. Per-channel scaling and bias.
If init is set to True, the scaling and bias are initialized such
that the mean and variance of the output activations of the first minibatch
are zero and one respectively.
Args:
name: variable scope.
x: input
logscale_factor: Used in actnorm_scale. Optimizes f(ls*s') instead of f(s)
where s' = s / ls. Helps in faster convergence.
reverse: forward or reverse operation.
init: Whether or not to do data-dependent initialization.
trainable:
Returns:
x: output after adding bias and scaling.
objective: log(sum(s)) | def actnorm(name, x, logscale_factor=3., reverse=False, init=False,
trainable=True):
"""x_{ij} = s x x_{ij} + b. Per-channel scaling and bias.
If init is set to True, the scaling and bias are initialized such
that the mean and variance of the output activations of the first minibatch
are zero and one respectively.
Args:
name: variable scope.
x: input
logscale_factor: Used in actnorm_scale. Optimizes f(ls*s') instead of f(s)
where s' = s / ls. Helps in faster convergence.
reverse: forward or reverse operation.
init: Whether or not to do data-dependent initialization.
trainable:
Returns:
x: output after adding bias and scaling.
objective: log(sum(s))
"""
var_arg_scope = arg_scope([get_variable_ddi], trainable=trainable)
var_scope = tf.variable_scope(name, reuse=tf.AUTO_REUSE)
with var_scope, var_arg_scope:
if not reverse:
x = actnorm_center(name + "_center", x, reverse, init=init)
x, objective = actnorm_scale(
name + "_scale", x, logscale_factor=logscale_factor,
reverse=reverse, init=init)
else:
x, objective = actnorm_scale(
name + "_scale", x, logscale_factor=logscale_factor,
reverse=reverse, init=init)
x = actnorm_center(name + "_center", x, reverse, init=init)
return x, objective |
Add a bias to x.
Initialize such that the output of the first minibatch is zero centered
per channel.
Args:
name: scope
x: 2-D or 4-D Tensor.
reverse: Forward or backward operation.
init: data-dependent initialization.
Returns:
x_center: (x + b), if reverse is True and (x - b) otherwise. | def actnorm_center(name, x, reverse=False, init=False):
"""Add a bias to x.
Initialize such that the output of the first minibatch is zero centered
per channel.
Args:
name: scope
x: 2-D or 4-D Tensor.
reverse: Forward or backward operation.
init: data-dependent initialization.
Returns:
x_center: (x + b), if reverse is True and (x - b) otherwise.
"""
shape = common_layers.shape_list(x)
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
assert len(shape) == 2 or len(shape) == 4
if len(shape) == 2:
x_mean = tf.reduce_mean(x, [0], keepdims=True)
b = get_variable_ddi("b", (1, shape[1]), initial_value=-x_mean,
init=init)
elif len(shape) == 4:
x_mean = tf.reduce_mean(x, [0, 1, 2], keepdims=True)
b = get_variable_ddi(
"b", (1, 1, 1, shape[3]), initial_value=-x_mean, init=init)
if not reverse:
x += b
else:
x -= b
return x |
Per-channel scaling of x. | def actnorm_scale(name, x, logscale_factor=3., reverse=False, init=False):
"""Per-channel scaling of x."""
x_shape = common_layers.shape_list(x)
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
# Variance initialization logic.
assert len(x_shape) == 2 or len(x_shape) == 4
if len(x_shape) == 2:
x_var = tf.reduce_mean(x**2, [0], keepdims=True)
logdet_factor = 1
var_shape = (1, x_shape[1])
elif len(x_shape) == 4:
x_var = tf.reduce_mean(x**2, [0, 1, 2], keepdims=True)
logdet_factor = x_shape[1]*x_shape[2]
var_shape = (1, 1, 1, x_shape[3])
init_value = tf.log(1.0 / (tf.sqrt(x_var) + 1e-6)) / logscale_factor
logs = get_variable_ddi("logs", var_shape, initial_value=init_value,
init=init)
logs = logs * logscale_factor
# Function and reverse function.
if not reverse:
x = x * tf.exp(logs)
else:
x = x * tf.exp(-logs)
# Objective calculation, h * w * sum(log|s|)
dlogdet = tf.reduce_sum(logs) * logdet_factor
if reverse:
dlogdet *= -1
return x, dlogdet |
1X1 convolution on x.
The 1X1 convolution is parametrized as P*L*(U + sign(s)*exp(log(s))) where
1. P is a permutation matrix.
2. L is a lower triangular matrix with diagonal entries unity.
3. U is a upper triangular matrix where the diagonal entries zero.
4. s is a vector.
sign(s) and P are fixed and the remaining are optimized. P, L, U and s are
initialized by the PLU decomposition of a random rotation matrix.
Args:
name: scope
x: Input Tensor.
reverse: whether the pass is from z -> x or x -> z.
Returns:
x_conv: x after a 1X1 convolution is applied on x.
objective: sum(log(s)) | def invertible_1x1_conv(name, x, reverse=False):
"""1X1 convolution on x.
The 1X1 convolution is parametrized as P*L*(U + sign(s)*exp(log(s))) where
1. P is a permutation matrix.
2. L is a lower triangular matrix with diagonal entries unity.
3. U is a upper triangular matrix where the diagonal entries zero.
4. s is a vector.
sign(s) and P are fixed and the remaining are optimized. P, L, U and s are
initialized by the PLU decomposition of a random rotation matrix.
Args:
name: scope
x: Input Tensor.
reverse: whether the pass is from z -> x or x -> z.
Returns:
x_conv: x after a 1X1 convolution is applied on x.
objective: sum(log(s))
"""
_, height, width, channels = common_layers.shape_list(x)
w_shape = [channels, channels]
# Random rotation-matrix Q
random_matrix = np.random.rand(channels, channels)
np_w = scipy.linalg.qr(random_matrix)[0].astype("float32")
# Initialize P,L,U and s from the LU decomposition of a random rotation matrix
np_p, np_l, np_u = scipy.linalg.lu(np_w)
np_s = np.diag(np_u)
np_sign_s = np.sign(np_s)
np_log_s = np.log(np.abs(np_s))
np_u = np.triu(np_u, k=1)
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
p = tf.get_variable("P", initializer=np_p, trainable=False)
l = tf.get_variable("L", initializer=np_l)
sign_s = tf.get_variable(
"sign_S", initializer=np_sign_s, trainable=False)
log_s = tf.get_variable("log_S", initializer=np_log_s)
u = tf.get_variable("U", initializer=np_u)
# W = P * L * (U + sign_s * exp(log_s))
l_mask = np.tril(np.ones([channels, channels], dtype=np.float32), -1)
l = l * l_mask + tf.eye(channels, channels)
u = u * np.transpose(l_mask) + tf.diag(sign_s * tf.exp(log_s))
w = tf.matmul(p, tf.matmul(l, u))
# If height or width cannot be statically determined then they end up as
# tf.int32 tensors, which cannot be directly multiplied with a floating
# point tensor without a cast.
objective = tf.reduce_sum(log_s) * tf.cast(height * width, log_s.dtype)
if not reverse:
w = tf.reshape(w, [1, 1] + w_shape)
x = tf.nn.conv2d(x, w, [1, 1, 1, 1], "SAME", data_format="NHWC")
else:
# TODO(b/111271662): Remove when supported.
def tpu_inv(m):
"""tf.linalg.inv workaround until it is supported on TPU."""
q, r = tf.linalg.qr(m)
return tf.linalg.triangular_solve(r, tf.transpose(q), lower=False)
w_inv = tf.reshape(tpu_inv(w), [1, 1]+w_shape)
x = tf.nn.conv2d(
x, w_inv, [1, 1, 1, 1], "SAME", data_format="NHWC")
objective *= -1
return x, objective |
Pad x and concatenates an edge bias across the depth of x.
The edge bias can be thought of as a binary feature which is unity when
the filter is being convolved over an edge and zero otherwise.
Args:
x: Input tensor, shape (NHWC)
filter_size: filter_size to determine padding.
Returns:
x_pad: Input tensor, shape (NHW(c+1)) | def add_edge_bias(x, filter_size):
"""Pad x and concatenates an edge bias across the depth of x.
The edge bias can be thought of as a binary feature which is unity when
the filter is being convolved over an edge and zero otherwise.
Args:
x: Input tensor, shape (NHWC)
filter_size: filter_size to determine padding.
Returns:
x_pad: Input tensor, shape (NHW(c+1))
"""
x_shape = common_layers.shape_list(x)
if filter_size[0] == 1 and filter_size[1] == 1:
return x
a = (filter_size[0] - 1) // 2 # vertical padding size
b = (filter_size[1] - 1) // 2 # horizontal padding size
padding = [[0, 0], [a, a], [b, b], [0, 0]]
x_bias = tf.zeros(x_shape[:-1] + [1])
x = tf.pad(x, padding)
x_pad = tf.pad(x_bias, padding, constant_values=1)
return tf.concat([x, x_pad], axis=3) |
Pad left across time and pad valid across the spatial components.
Also concats a binary feature that indicates if a feature is padded or not.
Args:
x: 5-D Tensor, (NTHWC)
filter_size: list of ints
dilations: list of ints, dilations - 1 specifies the number of holes
between two filter elements.
Returns:
x_pad: 5-D Tensor. | def time_pad(x, filter_size, dilations):
"""Pad left across time and pad valid across the spatial components.
Also concats a binary feature that indicates if a feature is padded or not.
Args:
x: 5-D Tensor, (NTHWC)
filter_size: list of ints
dilations: list of ints, dilations - 1 specifies the number of holes
between two filter elements.
Returns:
x_pad: 5-D Tensor.
"""
x_shape = common_layers.shape_list(x)
if filter_size == [1, 1, 1]:
return x
_, h, w = filter_size
eff_h = h + (h - 1)*(dilations[2] - 1)
eff_w = w + (w - 1)*(dilations[3] - 1)
a = (eff_h - 1) // 2 # vertical padding size
b = (eff_w - 1) // 2 # horizontal padding size
c = filter_size[0] - 1
# pad across edges.
padding = [[0, 0], [c, 0], [a, a], [b, b], [0, 0]]
# concat a binary feature across channels to indicate a padding.
# 1 indicates that the feature is a padding.
x_bias = tf.zeros(x_shape[:-1] + [1])
x_bias = tf.pad(x_bias, padding, constant_values=1)
x_pad = tf.pad(x, padding)
x_pad = tf.concat((x_bias, x_pad), axis=-1)
return x_pad |
Convolutional layer with edge bias padding and optional actnorm.
If x is 5-dimensional, actnorm is applied independently across every
time-step.
Args:
name: variable scope.
x: 4-D Tensor or 5-D Tensor of shape NHWC or NTHWC
output_channels: Number of output channels.
filter_size: list of ints, if None [3, 3] and [2, 3, 3] are defaults for
4-D and 5-D input tensors respectively.
stride: list of ints, default stride: 1
logscale_factor: see actnorm for parameter meaning.
apply_actnorm: if apply_actnorm the activations of the first minibatch
have zero mean and unit variance. Else, there is no scaling
applied.
conv_init: default or zeros. default is a normal distribution with 0.05 std.
dilations: List of integers, apply dilations.
Returns:
x: actnorm(conv2d(x))
Raises:
ValueError: if init is set to "zeros" and apply_actnorm is set to True. | def conv(name, x, output_channels, filter_size=None, stride=None,
logscale_factor=3.0, apply_actnorm=True, conv_init="default",
dilations=None):
"""Convolutional layer with edge bias padding and optional actnorm.
If x is 5-dimensional, actnorm is applied independently across every
time-step.
Args:
name: variable scope.
x: 4-D Tensor or 5-D Tensor of shape NHWC or NTHWC
output_channels: Number of output channels.
filter_size: list of ints, if None [3, 3] and [2, 3, 3] are defaults for
4-D and 5-D input tensors respectively.
stride: list of ints, default stride: 1
logscale_factor: see actnorm for parameter meaning.
apply_actnorm: if apply_actnorm the activations of the first minibatch
have zero mean and unit variance. Else, there is no scaling
applied.
conv_init: default or zeros. default is a normal distribution with 0.05 std.
dilations: List of integers, apply dilations.
Returns:
x: actnorm(conv2d(x))
Raises:
ValueError: if init is set to "zeros" and apply_actnorm is set to True.
"""
if conv_init == "zeros" and apply_actnorm:
raise ValueError("apply_actnorm is unstable when init is set to zeros.")
x_shape = common_layers.shape_list(x)
is_2d = len(x_shape) == 4
num_steps = x_shape[1]
# set filter_size, stride and in_channels
if is_2d:
if filter_size is None:
filter_size = [3, 3]
if stride is None:
stride = [1, 1]
if dilations is None:
dilations = [1, 1, 1, 1]
actnorm_func = actnorm
x = add_edge_bias(x, filter_size=filter_size)
conv_filter = tf.nn.conv2d
else:
if filter_size is None:
if num_steps == 1:
filter_size = [1, 3, 3]
else:
filter_size = [2, 3, 3]
if stride is None:
stride = [1, 1, 1]
if dilations is None:
dilations = [1, 1, 1, 1, 1]
actnorm_func = actnorm_3d
x = time_pad(x, filter_size=filter_size, dilations=dilations)
conv_filter = tf.nn.conv3d
in_channels = common_layers.shape_list(x)[-1]
filter_shape = filter_size + [in_channels, output_channels]
stride_shape = [1] + stride + [1]
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
if conv_init == "default":
initializer = default_initializer()
elif conv_init == "zeros":
initializer = tf.zeros_initializer()
w = tf.get_variable("W", filter_shape, tf.float32, initializer=initializer)
x = conv_filter(x, w, stride_shape, padding="VALID", dilations=dilations)
if apply_actnorm:
x, _ = actnorm_func("actnorm", x, logscale_factor=logscale_factor)
else:
x += tf.get_variable("b", [1, 1, 1, output_channels],
initializer=tf.zeros_initializer())
logs = tf.get_variable("logs", [1, output_channels],
initializer=tf.zeros_initializer())
x *= tf.exp(logs * logscale_factor)
return x |
2 layer conv block used in the affine coupling layer.
Args:
name: variable scope.
x: 4-D or 5-D Tensor.
mid_channels: Output channels of the second layer.
dilations: Optional, list of integers.
activation: relu or gatu.
If relu, the second layer is relu(W*x)
If gatu, the second layer is tanh(W1*x) * sigmoid(W2*x)
dropout: Dropout probability.
Returns:
x: 4-D Tensor: Output activations. | def conv_block(name, x, mid_channels, dilations=None, activation="relu",
dropout=0.0):
"""2 layer conv block used in the affine coupling layer.
Args:
name: variable scope.
x: 4-D or 5-D Tensor.
mid_channels: Output channels of the second layer.
dilations: Optional, list of integers.
activation: relu or gatu.
If relu, the second layer is relu(W*x)
If gatu, the second layer is tanh(W1*x) * sigmoid(W2*x)
dropout: Dropout probability.
Returns:
x: 4-D Tensor: Output activations.
"""
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
x_shape = common_layers.shape_list(x)
is_2d = len(x_shape) == 4
num_steps = x_shape[1]
if is_2d:
first_filter = [3, 3]
second_filter = [1, 1]
else:
# special case when number of steps equal 1 to avoid
# padding.
if num_steps == 1:
first_filter = [1, 3, 3]
else:
first_filter = [2, 3, 3]
second_filter = [1, 1, 1]
# Edge Padding + conv2d + actnorm + relu:
# [output: 512 channels]
x = conv("1_1", x, output_channels=mid_channels, filter_size=first_filter,
dilations=dilations)
x = tf.nn.relu(x)
x = get_dropout(x, rate=dropout)
# Padding + conv2d + actnorm + activation.
# [input, output: 512 channels]
if activation == "relu":
x = conv("1_2", x, output_channels=mid_channels,
filter_size=second_filter, dilations=dilations)
x = tf.nn.relu(x)
elif activation == "gatu":
# x = tanh(w1*x) * sigm(w2*x)
x_tanh = conv("1_tanh", x, output_channels=mid_channels,
filter_size=second_filter, dilations=dilations)
x_sigm = conv("1_sigm", x, output_channels=mid_channels,
filter_size=second_filter, dilations=dilations)
x = tf.nn.tanh(x_tanh) * tf.nn.sigmoid(x_sigm)
x = get_dropout(x, rate=dropout)
return x |
Dilated convolutional stack.
Features at different rates are computed independently using a 3 layer
convolutional stack and added.
Args:
name: variable scope.
x: 5-D Tensor.
mid_channels: Number of output channels of the first layer in the conv
stack.
output_channels: Number of output channels of the last layer.
dilation_rates: A list of dilation rates.
activation: Can be either "relu" or "gatu"
dropout: dropout.
Returns:
output: 5-D Tensor. | def dilated_conv_stack(name, x, mid_channels, output_channels,
dilation_rates, activation="relu",
dropout=0.0):
"""Dilated convolutional stack.
Features at different rates are computed independently using a 3 layer
convolutional stack and added.
Args:
name: variable scope.
x: 5-D Tensor.
mid_channels: Number of output channels of the first layer in the conv
stack.
output_channels: Number of output channels of the last layer.
dilation_rates: A list of dilation rates.
activation: Can be either "relu" or "gatu"
dropout: dropout.
Returns:
output: 5-D Tensor.
"""
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
output = 0.0
for dil_ind, dil_rate in enumerate(dilation_rates):
# TODO(mechcoder) try (concat across channels + 1x1) modulo memory issues.
curr_out = conv_stack("dil_%d" % dil_ind, x, mid_channels=mid_channels,
output_channels=output_channels, dilations=dil_rate,
activation=activation, dropout=dropout)
output += curr_out
return output |
3-layer convolutional stack.
Args:
name: variable scope.
x: 5-D Tensor.
mid_channels: Number of output channels of the first layer.
output_channels: Number of output channels.
dilations: Dilations to apply in the first 3x3 layer and the last 3x3 layer.
By default, apply no dilations.
activation: relu or gatu.
If relu, the second layer is relu(W*x)
If gatu, the second layer is tanh(W1*x) * sigmoid(W2*x)
dropout: float, 0.0
Returns:
output: output of 3 layer conv network. | def conv_stack(name, x, mid_channels, output_channels, dilations=None,
activation="relu", dropout=0.0):
"""3-layer convolutional stack.
Args:
name: variable scope.
x: 5-D Tensor.
mid_channels: Number of output channels of the first layer.
output_channels: Number of output channels.
dilations: Dilations to apply in the first 3x3 layer and the last 3x3 layer.
By default, apply no dilations.
activation: relu or gatu.
If relu, the second layer is relu(W*x)
If gatu, the second layer is tanh(W1*x) * sigmoid(W2*x)
dropout: float, 0.0
Returns:
output: output of 3 layer conv network.
"""
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
x = conv_block("conv_block", x, mid_channels=mid_channels,
dilations=dilations, activation=activation,
dropout=dropout)
# Final layer.
x = conv("zeros", x, apply_actnorm=False, conv_init="zeros",
output_channels=output_channels, dilations=dilations)
return x |
Reversible additive coupling layer.
Args:
name: variable scope.
x: 4-D Tensor, shape=(NHWC).
mid_channels: number of channels in the coupling layer.
reverse: Forward or reverse operation.
activation: "relu" or "gatu"
dropout: default, 0.0
Returns:
output: 4-D Tensor, shape=(NHWC)
objective: 0.0 | def additive_coupling(name, x, mid_channels=512, reverse=False,
activation="relu", dropout=0.0):
"""Reversible additive coupling layer.
Args:
name: variable scope.
x: 4-D Tensor, shape=(NHWC).
mid_channels: number of channels in the coupling layer.
reverse: Forward or reverse operation.
activation: "relu" or "gatu"
dropout: default, 0.0
Returns:
output: 4-D Tensor, shape=(NHWC)
objective: 0.0
"""
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
output_channels = common_layers.shape_list(x)[-1] // 2
x1, x2 = tf.split(x, num_or_size_splits=2, axis=-1)
z1 = x1
shift = conv_stack("nn", x1, mid_channels, output_channels=output_channels,
activation=activation, dropout=dropout)
if not reverse:
z2 = x2 + shift
else:
z2 = x2 - shift
return tf.concat([z1, z2], axis=3), 0.0 |
Reversible affine coupling layer.
Args:
name: variable scope.
x: 4-D Tensor.
mid_channels: number of channels in the coupling layer.
activation: Can be either "relu" or "gatu".
reverse: Forward or reverse operation.
dropout: default, 0.0
Returns:
output: x shifted and scaled by an affine transformation.
objective: log-determinant of the jacobian | def affine_coupling(name, x, mid_channels=512, activation="relu",
reverse=False, dropout=0.0):
"""Reversible affine coupling layer.
Args:
name: variable scope.
x: 4-D Tensor.
mid_channels: number of channels in the coupling layer.
activation: Can be either "relu" or "gatu".
reverse: Forward or reverse operation.
dropout: default, 0.0
Returns:
output: x shifted and scaled by an affine transformation.
objective: log-determinant of the jacobian
"""
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
x_shape = common_layers.shape_list(x)
x1, x2 = tf.split(x, num_or_size_splits=2, axis=-1)
# scale, shift = NN(x1)
# If reverse:
# z2 = scale * (x2 + shift)
# Else:
# z2 = (x2 / scale) - shift
z1 = x1
log_scale_and_shift = conv_stack(
"nn", x1, mid_channels, x_shape[-1], activation=activation,
dropout=dropout)
shift = log_scale_and_shift[:, :, :, 0::2]
scale = tf.nn.sigmoid(log_scale_and_shift[:, :, :, 1::2] + 2.0)
if not reverse:
z2 = (x2 + shift) * scale
else:
z2 = x2 / scale - shift
objective = tf.reduce_sum(tf.log(scale), axis=[1, 2, 3])
if reverse:
objective *= -1
return tf.concat([z1, z2], axis=3), objective |
Block-wise spatial squeezing of x to increase the number of channels.
Args:
name: Used for variable scoping.
x: 4-D Tensor of shape (batch_size X H X W X C)
factor: Factor by which the spatial dimensions should be squeezed.
reverse: Squueze or unsqueeze operation.
Returns:
x: 4-D Tensor of shape (batch_size X (H//factor) X (W//factor) X
(cXfactor^2). If reverse is True, then it is factor = (1 / factor) | def squeeze(name, x, factor=2, reverse=True):
"""Block-wise spatial squeezing of x to increase the number of channels.
Args:
name: Used for variable scoping.
x: 4-D Tensor of shape (batch_size X H X W X C)
factor: Factor by which the spatial dimensions should be squeezed.
reverse: Squueze or unsqueeze operation.
Returns:
x: 4-D Tensor of shape (batch_size X (H//factor) X (W//factor) X
(cXfactor^2). If reverse is True, then it is factor = (1 / factor)
"""
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
shape = common_layers.shape_list(x)
if factor == 1:
return x
height = int(shape[1])
width = int(shape[2])
n_channels = int(shape[3])
if not reverse:
assert height % factor == 0 and width % factor == 0
x = tf.reshape(x, [-1, height//factor, factor,
width//factor, factor, n_channels])
x = tf.transpose(x, [0, 1, 3, 5, 2, 4])
x = tf.reshape(x, [-1, height//factor, width //
factor, n_channels*factor*factor])
else:
x = tf.reshape(
x, (-1, height, width, int(n_channels/factor**2), factor, factor))
x = tf.transpose(x, [0, 1, 4, 2, 5, 3])
x = tf.reshape(x, (-1, int(height*factor),
int(width*factor), int(n_channels/factor**2)))
return x |
Get a list of valid dilation rates.
Args:
hparams: HParams.
width: spatial dimension. Ensures that the effective filter size is
not larger than the spatial dimension.
Returns:
allowed_dilations: A list of dilation rates. | def get_dilation_rates(hparams, width):
"""Get a list of valid dilation rates.
Args:
hparams: HParams.
width: spatial dimension. Ensures that the effective filter size is
not larger than the spatial dimension.
Returns:
allowed_dilations: A list of dilation rates.
"""
# dil_rate=1 means no dilation.
allowed_dilations = [[1]*5]
apply_dilations = hparams.get("latent_apply_dilations", False)
dilation_rates = hparams.get("latent_dilation_rates", [1, 3])
if apply_dilations:
for rate in dilation_rates:
# k + (k - 1) * rate but k is harcoded to be 3 everywhere.
filter_size = 3 + 2 * rate
if filter_size <= width:
curr_dilation = [1, 1, rate+1, rate+1, 1]
allowed_dilations.append(curr_dilation)
return allowed_dilations |
Network that maps a time-indexed list of 3-D latents to a gaussian.
Args:
name: variable scope.
x: List of 4-D Tensors indexed by time, (NHWC)
hparams: tf.contrib.training.Hparams.
output_channels: int, Number of channels of the output gaussian mean.
Returns:
dist: tfp.distributions.Normal | def temporal_latent_to_dist(name, x, hparams, output_channels=None):
"""Network that maps a time-indexed list of 3-D latents to a gaussian.
Args:
name: variable scope.
x: List of 4-D Tensors indexed by time, (NHWC)
hparams: tf.contrib.training.Hparams.
output_channels: int, Number of channels of the output gaussian mean.
Returns:
dist: tfp.distributions.Normal
"""
_, _, width, _, res_channels = common_layers.shape_list(x)
if output_channels is None:
output_channels = res_channels
dilation_rates = get_dilation_rates(hparams, width)
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
h = x
for i in range(hparams.latent_encoder_depth):
if hparams.latent_apply_dilations:
h2 = dilated_conv_stack("dil_latent_3d_res_%d" % i, h,
mid_channels=hparams.latent_encoder_width,
output_channels=res_channels,
dilation_rates=dilation_rates,
activation=hparams.latent_activation,
dropout=hparams.latent_dropout)
else:
h2 = conv_stack("latent_3d_res_%d" % i, h,
mid_channels=hparams.latent_encoder_width,
output_channels=res_channels,
activation=hparams.latent_activation,
dropout=hparams.latent_dropout)
h += h2
# take last activation that should capture all context since padding is
# on left.
h = h[:, -1, :, :, :]
h = conv("res_final", h, apply_actnorm=False, conv_init="zeros",
output_channels=2*output_channels, filter_size=[1, 1])
mean, log_scale = h[:, :, :, 0::2], h[:, :, :, 1::2]
return tfp.distributions.Normal(mean, tf.exp(log_scale)) |
A 3x3 convolution mapping x to a standard normal distribution at init.
Args:
name: variable scope.
x: 4-D Tensor.
output_channels: number of channels of the mean and std. | def single_conv_dist(name, x, output_channels=None):
"""A 3x3 convolution mapping x to a standard normal distribution at init.
Args:
name: variable scope.
x: 4-D Tensor.
output_channels: number of channels of the mean and std.
"""
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
x_shape = common_layers.shape_list(x)
if output_channels is None:
output_channels = x_shape[-1]
mean_log_scale = conv("conv2d", x, output_channels=2*output_channels,
conv_init="zeros", apply_actnorm=False)
mean = mean_log_scale[:, :, :, 0::2]
log_scale = mean_log_scale[:, :, :, 1::2]
return tf.distributions.Normal(mean, tf.exp(log_scale)) |
Adds isotropic gaussian-noise to each latent.
Args:
latents: 4-D or 5-D tensor, shape=(NTHWC) or (NHWC).
hparams: HParams.
Returns:
latents: latents with isotropic gaussian noise appended. | def noise_op(latents, hparams):
"""Adds isotropic gaussian-noise to each latent.
Args:
latents: 4-D or 5-D tensor, shape=(NTHWC) or (NHWC).
hparams: HParams.
Returns:
latents: latents with isotropic gaussian noise appended.
"""
if hparams.latent_noise == 0 or hparams.mode != tf.estimator.ModeKeys.TRAIN:
return latents
latent_shape = common_layers.shape_list(latents)
return latents + tf.random_normal(latent_shape, stddev=hparams.latent_noise) |
Merge level_dist and latent_dist.
new_dist ~ N(level_dist.mean + latent_dis.mean, std) where std is determined
according to merge_std.
Args:
level_dist: instance of tfp.distributions.Normal
latent_dist: instance of tfp.distributions.Normal
merge_std: can be "prev_level", "prev_step" or "normal".
Returns:
merged_dist: instance of tfp.distributions.Normal | def merge_level_and_latent_dist(level_dist, latent_dist,
merge_std="prev_level"):
"""Merge level_dist and latent_dist.
new_dist ~ N(level_dist.mean + latent_dis.mean, std) where std is determined
according to merge_std.
Args:
level_dist: instance of tfp.distributions.Normal
latent_dist: instance of tfp.distributions.Normal
merge_std: can be "prev_level", "prev_step" or "normal".
Returns:
merged_dist: instance of tfp.distributions.Normal
"""
level_mean, level_std = level_dist.loc, level_dist.scale
latent_mean, latent_std = latent_dist.loc, latent_dist.scale
new_mean = level_mean + latent_mean
if merge_std == "normal":
z_shape = common_layers.shape_list(latent_mean)
log_scale = tf.get_variable(
"merge_std", shape=z_shape, dtype=tf.float32,
initializer=tf.zeros_initializer(), trainable=False)
scale = tf.exp(log_scale * 3.0)
elif merge_std == "prev_level":
scale = level_std
elif merge_std == "prev_step":
scale = latent_std
return tfp.distributions.Normal(loc=new_mean, scale=scale) |
Returns a conditional prior for each level.
Args:
prior_dist: Distribution conditioned on the previous levels.
z: Tensor, output of the previous levels.
latent: Tensor or a list of tensors to condition the latent_distribution.
hparams: next_frame_glow hparams.
state: Current LSTM state. Used only if hparams.latent_dist_encoder is
a lstm.
Raises:
ValueError: If hparams.latent_dist_encoder is "pointwise" and if the shape
of latent is different from z. | def level_cond_prior(prior_dist, z, latent, hparams, state):
"""Returns a conditional prior for each level.
Args:
prior_dist: Distribution conditioned on the previous levels.
z: Tensor, output of the previous levels.
latent: Tensor or a list of tensors to condition the latent_distribution.
hparams: next_frame_glow hparams.
state: Current LSTM state. Used only if hparams.latent_dist_encoder is
a lstm.
Raises:
ValueError: If hparams.latent_dist_encoder is "pointwise" and if the shape
of latent is different from z.
"""
latent_dist_encoder = hparams.get("latent_dist_encoder", None)
latent_skip = hparams.get("latent_skip", False)
if latent_dist_encoder == "pointwise":
last_latent = latent
merge_std = hparams.level_scale
latent_shape = common_layers.shape_list(latent)
z_shape = common_layers.shape_list(z)
if latent_shape != z_shape:
raise ValueError("Expected latent_shape to be %s, got %s" %
(latent_shape, z_shape))
latent_dist = scale_gaussian_prior(
"latent_prior", latent, logscale_factor=3.0)
cond_dist = merge_level_and_latent_dist(prior_dist, latent_dist,
merge_std=merge_std)
elif latent_dist_encoder == "conv_net":
output_channels = common_layers.shape_list(z)[-1]
last_latent = latent[-1]
latent_stack = tf.concat([prior_dist.loc] + latent, axis=-1)
latent_stack = noise_op(latent_stack, hparams)
cond_dist = latent_to_dist(
"latent_stack", latent_stack, hparams=hparams,
output_channels=output_channels)
elif latent_dist_encoder == "conv3d_net":
last_latent = latent[-1]
output_channels = common_layers.shape_list(last_latent)[-1]
num_steps = len(latent)
# Stack across time.
cond_latents = tf.stack(latent, axis=1)
# Concat latents from previous levels across channels.
prev_latents = tf.tile(tf.expand_dims(prior_dist.loc, axis=1),
[1, num_steps, 1, 1, 1])
cond_latents = tf.concat((cond_latents, prev_latents), axis=-1)
cond_latents = noise_op(cond_latents, hparams)
cond_dist = temporal_latent_to_dist(
"latent_stack", cond_latents, hparams, output_channels=output_channels)
elif latent_dist_encoder == "conv_lstm":
last_latent = latent
output_channels = common_layers.shape_list(z)[-1]
latent_stack = tf.concat((prior_dist.loc, latent), axis=-1)
latent_stack = noise_op(latent_stack, hparams)
_, state = common_video.conv_lstm_2d(
latent_stack, state, hparams.latent_encoder_width, kernel_size=3,
name="conv_lstm")
cond_dist = single_conv_dist(
"state_to_dist", state.h, output_channels=output_channels)
if latent_skip:
new_mean = cond_dist.loc + last_latent
cond_dist = tfp.distributions.Normal(new_mean, cond_dist.scale)
return cond_dist.loc, cond_dist.scale, state |
Distribution on z_t conditioned on z_{t-1} and latent.
Args:
name: variable scope.
z: 4-D Tensor.
latent: optional,
if hparams.latent_dist_encoder == "pointwise", this is a list
of 4-D Tensors of length hparams.num_cond_latents.
else, this is just a 4-D Tensor
The first-three dimensions of the latent should be the same as z.
hparams: next_frame_glow_hparams.
condition: Whether or not to condition the distribution on latent.
state: tf.nn.rnn_cell.LSTMStateTuple.
the current state of a LSTM used to model the distribution. Used
only if hparams.latent_dist_encoder = "conv_lstm".
temperature: float, temperature with which to sample from the Gaussian.
Returns:
prior_dist: instance of tfp.distributions.Normal
state: Returns updated state.
Raises:
ValueError: If hparams.latent_dist_encoder is "pointwise" and if the shape
of latent is different from z. | def compute_prior(name, z, latent, hparams, condition=False, state=None,
temperature=1.0):
"""Distribution on z_t conditioned on z_{t-1} and latent.
Args:
name: variable scope.
z: 4-D Tensor.
latent: optional,
if hparams.latent_dist_encoder == "pointwise", this is a list
of 4-D Tensors of length hparams.num_cond_latents.
else, this is just a 4-D Tensor
The first-three dimensions of the latent should be the same as z.
hparams: next_frame_glow_hparams.
condition: Whether or not to condition the distribution on latent.
state: tf.nn.rnn_cell.LSTMStateTuple.
the current state of a LSTM used to model the distribution. Used
only if hparams.latent_dist_encoder = "conv_lstm".
temperature: float, temperature with which to sample from the Gaussian.
Returns:
prior_dist: instance of tfp.distributions.Normal
state: Returns updated state.
Raises:
ValueError: If hparams.latent_dist_encoder is "pointwise" and if the shape
of latent is different from z.
"""
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
if isinstance(condition, bool):
condition = tf.constant(condition, dtype=tf.bool)
prior_dist = single_conv_dist("level_prior", z)
prior_mean, prior_scale = prior_dist.loc, prior_dist.scale
if latent is None:
mean, scale = prior_mean, prior_scale
else:
cond_mean, cond_scale, state = level_cond_prior(
prior_dist, z, latent, hparams, state)
mean, scale = tf.cond(
condition, lambda: (cond_mean, cond_scale),
lambda: (prior_mean, prior_scale))
dist = TemperedNormal(mean, scale, temperature)
return dist, state |
Splits / concatenates x into x1 and x2 across number of channels.
For the forward pass, x2 is assumed be gaussian,
i.e P(x2 | x1) ~ N(mu, sigma) where mu and sigma are the outputs of
a network conditioned on x1 and optionally on cond_latents.
For the reverse pass, x2 is determined from mu(x1) and sigma(x1).
This is deterministic/stochastic depending on whether eps is provided.
Args:
name: variable scope.
x: 4-D Tensor, shape (NHWC).
reverse: Forward or reverse pass.
eps: If eps is provided, x2 is set to be mu(x1) + eps * sigma(x1).
eps_std: Sample x2 with the provided eps_std.
cond_latents: optionally condition x2 on cond_latents.
hparams: next_frame_glow hparams.
state: tf.nn.rnn_cell.LSTMStateTuple.. Current state of the LSTM over z_2.
Used only when hparams.latent_dist_encoder == "conv_lstm"
condition: bool, Whether or not to condition the distribution on
cond_latents.
temperature: Temperature with which to sample from the gaussian.
Returns:
If reverse:
x: 4-D Tensor, concats input and x2 across channels.
x2: 4-D Tensor, a sample from N(mu(x1), sigma(x1))
Else:
x1: 4-D Tensor, Output of the split operation.
logpb: log-probability of x2 belonging to mu(x1), sigma(x1)
eps: 4-D Tensor, (x2 - mu(x1)) / sigma(x1)
x2: 4-D Tensor, Latent representation at the current level.
state: Current LSTM state.
4-D Tensor, only if hparams.latent_dist_encoder is set to conv_lstm.
Raises:
ValueError: If latent is provided and shape is not equal to NHW(C/2)
where (NHWC) is the size of x. | def split(name, x, reverse=False, eps=None, eps_std=None, cond_latents=None,
hparams=None, state=None, condition=False, temperature=1.0):
"""Splits / concatenates x into x1 and x2 across number of channels.
For the forward pass, x2 is assumed be gaussian,
i.e P(x2 | x1) ~ N(mu, sigma) where mu and sigma are the outputs of
a network conditioned on x1 and optionally on cond_latents.
For the reverse pass, x2 is determined from mu(x1) and sigma(x1).
This is deterministic/stochastic depending on whether eps is provided.
Args:
name: variable scope.
x: 4-D Tensor, shape (NHWC).
reverse: Forward or reverse pass.
eps: If eps is provided, x2 is set to be mu(x1) + eps * sigma(x1).
eps_std: Sample x2 with the provided eps_std.
cond_latents: optionally condition x2 on cond_latents.
hparams: next_frame_glow hparams.
state: tf.nn.rnn_cell.LSTMStateTuple.. Current state of the LSTM over z_2.
Used only when hparams.latent_dist_encoder == "conv_lstm"
condition: bool, Whether or not to condition the distribution on
cond_latents.
temperature: Temperature with which to sample from the gaussian.
Returns:
If reverse:
x: 4-D Tensor, concats input and x2 across channels.
x2: 4-D Tensor, a sample from N(mu(x1), sigma(x1))
Else:
x1: 4-D Tensor, Output of the split operation.
logpb: log-probability of x2 belonging to mu(x1), sigma(x1)
eps: 4-D Tensor, (x2 - mu(x1)) / sigma(x1)
x2: 4-D Tensor, Latent representation at the current level.
state: Current LSTM state.
4-D Tensor, only if hparams.latent_dist_encoder is set to conv_lstm.
Raises:
ValueError: If latent is provided and shape is not equal to NHW(C/2)
where (NHWC) is the size of x.
"""
# TODO(mechcoder) Change the return type to be a dict.
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
if not reverse:
x1, x2 = tf.split(x, num_or_size_splits=2, axis=-1)
# objective: P(x2|x1) ~N(x2 ; NN(x1))
prior_dist, state = compute_prior(
"prior_on_z2", x1, cond_latents, hparams, condition, state=state)
logpb = tf.reduce_sum(prior_dist.log_prob(x2), axis=[1, 2, 3])
eps = get_eps(prior_dist, x2)
return x1, logpb, eps, x2, state
else:
prior_dist, state = compute_prior(
"prior_on_z2", x, cond_latents, hparams, condition, state=state,
temperature=temperature)
if eps is not None:
x2 = set_eps(prior_dist, eps)
elif eps_std is not None:
x2 = eps_std * tf.random_normal(common_layers.shape_list(x))
else:
x2 = prior_dist.sample()
return tf.concat([x, x2], 3), x2, state |
One step of glow generative flow.
Actnorm + invertible 1X1 conv + affine_coupling.
Args:
name: used for variable scope.
x: input
hparams: coupling_width is the only hparam that is being used in
this function.
reverse: forward or reverse pass.
Returns:
z: Output of one step of reversible flow. | def revnet_step(name, x, hparams, reverse=True):
"""One step of glow generative flow.
Actnorm + invertible 1X1 conv + affine_coupling.
Args:
name: used for variable scope.
x: input
hparams: coupling_width is the only hparam that is being used in
this function.
reverse: forward or reverse pass.
Returns:
z: Output of one step of reversible flow.
"""
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
if hparams.coupling == "additive":
coupling_layer = functools.partial(
additive_coupling, name="additive", reverse=reverse,
mid_channels=hparams.coupling_width,
activation=hparams.activation, dropout=hparams.coupling_dropout)
else:
coupling_layer = functools.partial(
affine_coupling, name="affine", reverse=reverse,
mid_channels=hparams.coupling_width,
activation=hparams.activation, dropout=hparams.coupling_dropout)
ops = [
functools.partial(actnorm, name="actnorm", reverse=reverse),
functools.partial(invertible_1x1_conv, name="invertible",
reverse=reverse), coupling_layer]
if reverse:
ops = ops[::-1]
objective = 0.0
for op in ops:
x, curr_obj = op(x=x)
objective += curr_obj
return x, objective |
hparams.depth' steps of generative flow.
Args:
name: variable scope for the revnet block.
x: 4-D Tensor, shape=(NHWC).
hparams: HParams.
reverse: bool, forward or backward pass.
Returns:
x: 4-D Tensor, shape=(NHWC).
objective: float. | def revnet(name, x, hparams, reverse=True):
"""'hparams.depth' steps of generative flow.
Args:
name: variable scope for the revnet block.
x: 4-D Tensor, shape=(NHWC).
hparams: HParams.
reverse: bool, forward or backward pass.
Returns:
x: 4-D Tensor, shape=(NHWC).
objective: float.
"""
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
steps = np.arange(hparams.depth)
if reverse:
steps = steps[::-1]
objective = 0.0
for step in steps:
x, curr_obj = revnet_step(
"revnet_step_%d" % step, x, hparams, reverse=reverse)
objective += curr_obj
return x, objective |
Returns N(s^i * z^i, std^i) where s^i and std^i are pre-component.
s^i is a learnable parameter with identity initialization.
std^i is optionally learnable with identity initialization.
Args:
name: variable scope.
z: input_tensor
logscale_factor: equivalent to scaling up the learning_rate by a factor
of logscale_factor.
trainable: Whether or not std^i is learnt. | def scale_gaussian_prior(name, z, logscale_factor=3.0, trainable=True):
"""Returns N(s^i * z^i, std^i) where s^i and std^i are pre-component.
s^i is a learnable parameter with identity initialization.
std^i is optionally learnable with identity initialization.
Args:
name: variable scope.
z: input_tensor
logscale_factor: equivalent to scaling up the learning_rate by a factor
of logscale_factor.
trainable: Whether or not std^i is learnt.
"""
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
z_shape = common_layers.shape_list(z)
latent_multiplier = tf.get_variable(
"latent_multiplier", shape=z_shape, dtype=tf.float32,
initializer=tf.ones_initializer())
log_scale = tf.get_variable(
"log_scale_latent", shape=z_shape, dtype=tf.float32,
initializer=tf.zeros_initializer(), trainable=trainable)
log_scale = log_scale * logscale_factor
return tfp.distributions.Normal(
loc=latent_multiplier * z, scale=tf.exp(log_scale)) |
Unconditional prior distribution.
Args:
name: variable scope
z_shape: Shape of the mean / scale of the prior distribution.
learn_prior: Possible options are "normal" and "single_conv".
If set to "single_conv", the gaussian is parametrized by a
single convolutional layer whose input are an array of zeros
and initialized such that the mean and std are zero and one.
If set to "normal", the prior is just a Gaussian with zero
mean and unit variance.
temperature: Temperature with which to sample from the Gaussian.
Returns:
objective: 1-D Tensor shape=(batch_size,) summed across spatial components.
Raises:
ValueError: If learn_prior not in "normal" or "single_conv" | def top_prior(name, z_shape, learn_prior="normal", temperature=1.0):
"""Unconditional prior distribution.
Args:
name: variable scope
z_shape: Shape of the mean / scale of the prior distribution.
learn_prior: Possible options are "normal" and "single_conv".
If set to "single_conv", the gaussian is parametrized by a
single convolutional layer whose input are an array of zeros
and initialized such that the mean and std are zero and one.
If set to "normal", the prior is just a Gaussian with zero
mean and unit variance.
temperature: Temperature with which to sample from the Gaussian.
Returns:
objective: 1-D Tensor shape=(batch_size,) summed across spatial components.
Raises:
ValueError: If learn_prior not in "normal" or "single_conv"
"""
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
h = tf.zeros(z_shape, dtype=tf.float32)
if learn_prior == "normal":
prior_dist = tfp.distributions.Normal(h, tf.exp(h))
elif learn_prior == "single_conv":
prior_dist = single_conv_dist("top_learn_prior", h)
else:
raise ValueError("Expected learn_prior to be normal or single_conv "
"got %s" % learn_prior)
return TemperedNormal(prior_dist.loc, prior_dist.scale, temperature) |
Replaces x^i with q^i(x) = U(x, x + 1.0 / 256.0).
Args:
x: 4-D Tensor of shape (NHWC)
n_bits: optional.
Returns:
x: x ~ U(x, x + 1.0 / 256)
objective: Equivalent to -q(x)*log(q(x)). | def uniform_binning_correction(x, n_bits=8):
"""Replaces x^i with q^i(x) = U(x, x + 1.0 / 256.0).
Args:
x: 4-D Tensor of shape (NHWC)
n_bits: optional.
Returns:
x: x ~ U(x, x + 1.0 / 256)
objective: Equivalent to -q(x)*log(q(x)).
"""
n_bins = 2**n_bits
batch_size, height, width, n_channels = common_layers.shape_list(x)
hwc = float(height * width * n_channels)
x = x + tf.random_uniform(
shape=(batch_size, height, width, n_channels),
minval=0.0, maxval=1.0/n_bins)
objective = -np.log(n_bins) * hwc * tf.ones(batch_size)
return x, objective |
Glow encoder-decoder. n_levels of (Squeeze + Flow + Split.) operations.
Args:
name: variable scope.
x: 4-D Tensor, shape=(NHWC).
hparams: HParams.
eps: Stores (glow(x) - mu) / sigma during the forward pass.
Used only to test if the network is reversible.
reverse: Forward or reverse pass.
cond_latents: list of lists of tensors.
outer length equals hparams.num_cond_latents
innter length equals hparams.num_levels - 1.
condition: If set to True, condition the encoder/decoder on cond_latents.
states: LSTM states, used only if hparams.latent_dist_encoder is set
to "conv_lstm.
temperature: Temperature set during sampling.
Returns:
x: If reverse, decoded image, else the encoded glow latent representation.
objective: log-likelihood.
eps: list of tensors, shape=(num_levels-1).
Stores (glow(x) - mu_level(x)) / sigma_level(x)) for each level.
all_latents: list of tensors, shape=(num_levels-1).
Latent representatios for each level.
new_states: list of tensors, shape=(num_levels-1).
useful only if hparams.latent_dist_encoder="conv_lstm", returns
the current state of each level. | def encoder_decoder(name, x, hparams, eps=None, reverse=False,
cond_latents=None, condition=False, states=None,
temperature=1.0):
"""Glow encoder-decoder. n_levels of (Squeeze + Flow + Split.) operations.
Args:
name: variable scope.
x: 4-D Tensor, shape=(NHWC).
hparams: HParams.
eps: Stores (glow(x) - mu) / sigma during the forward pass.
Used only to test if the network is reversible.
reverse: Forward or reverse pass.
cond_latents: list of lists of tensors.
outer length equals hparams.num_cond_latents
innter length equals hparams.num_levels - 1.
condition: If set to True, condition the encoder/decoder on cond_latents.
states: LSTM states, used only if hparams.latent_dist_encoder is set
to "conv_lstm.
temperature: Temperature set during sampling.
Returns:
x: If reverse, decoded image, else the encoded glow latent representation.
objective: log-likelihood.
eps: list of tensors, shape=(num_levels-1).
Stores (glow(x) - mu_level(x)) / sigma_level(x)) for each level.
all_latents: list of tensors, shape=(num_levels-1).
Latent representatios for each level.
new_states: list of tensors, shape=(num_levels-1).
useful only if hparams.latent_dist_encoder="conv_lstm", returns
the current state of each level.
"""
# TODO(mechcoder) Change return_type to a dict to be backward compatible.
with tf.variable_scope(name, reuse=tf.AUTO_REUSE):
if states and len(states) != hparams.n_levels - 1:
raise ValueError("Expected length of states to be %d, got %d" %
(hparams.n_levels - 1, len(states)))
if states is None:
states = [None] * (hparams.n_levels - 1)
if eps and len(eps) != hparams.n_levels - 1:
raise ValueError("Expected length of eps to be %d, got %d" %
(hparams.n_levels - 1, len(eps)))
if eps is None:
eps = [None] * (hparams.n_levels - 1)
check_cond_latents(cond_latents, hparams)
objective = 0.0
all_eps = []
all_latents = []
new_states = []
if not reverse:
# Squeeze + Flow + Split
for level in range(hparams.n_levels):
x = squeeze("squeeze_%d" % level, x, factor=2, reverse=False)
x, obj = revnet("revnet_%d" % level, x, hparams, reverse=False)
objective += obj
if level < hparams.n_levels - 1:
curr_cond_latents = get_cond_latents_at_level(
cond_latents, level, hparams)
x, obj, eps, z, state = split("split_%d" % level, x, reverse=False,
cond_latents=curr_cond_latents,
condition=condition,
hparams=hparams, state=states[level])
objective += obj
all_eps.append(eps)
all_latents.append(z)
new_states.append(state)
return x, objective, all_eps, all_latents, new_states
else:
for level in reversed(range(hparams.n_levels)):
if level < hparams.n_levels - 1:
curr_cond_latents = get_cond_latents_at_level(
cond_latents, level, hparams)
x, latent, state = split("split_%d" % level, x, eps=eps[level],
reverse=True, cond_latents=curr_cond_latents,
condition=condition, hparams=hparams,
state=states[level],
temperature=temperature)
new_states.append(state)
all_latents.append(latent)
x, obj = revnet(
"revnet_%d" % level, x, hparams=hparams, reverse=True)
objective += obj
x = squeeze("squeeze_%d" % level, x, reverse=True)
return x, objective, all_latents[::-1], new_states[::-1] |
A custom getter function for float32 parameters and bfloat16 activations.
Args:
getter: custom getter
*args: arguments
**kwargs: keyword arguments
Returns:
variables with the correct dtype.
Raises:
KeyError: if "dtype" is not provided as a kwarg. | def bfloat16_activations_var_getter(getter, *args, **kwargs):
"""A custom getter function for float32 parameters and bfloat16 activations.
Args:
getter: custom getter
*args: arguments
**kwargs: keyword arguments
Returns:
variables with the correct dtype.
Raises:
KeyError: if "dtype" is not provided as a kwarg.
"""
requested_dtype = kwargs["dtype"]
if requested_dtype == tf.bfloat16:
kwargs["dtype"] = tf.float32
var = getter(*args, **kwargs)
# This if statement is needed to guard the cast, because batch norm
# assigns directly to the return value of this custom getter. The cast
# makes the return value not a variable so it cannot be assigned. Batch
# norm variables are always in fp32 so this if statement is never
# triggered for them.
if var.dtype.base_dtype != requested_dtype:
var = tf.cast(var, requested_dtype)
return var |
A custom getter function for float32 parameters and float16 activations.
This function ensures the following:
1. All variables requested with type fp16 are stored as type fp32.
2. All variables requested with type fp32 are returned as type fp16.
See https://docs.nvidia.com/deeplearning/sdk/mixed-precision-training/
#training_tensorflow for more information on this strategy.
Args:
getter: custom getter
*args: arguments
**kwargs: keyword arguments
Returns:
variables with the correct dtype.
Raises:
KeyError: if "dtype" is not provided as a kwarg. | def float16_activations_var_getter(getter, *args, **kwargs):
"""A custom getter function for float32 parameters and float16 activations.
This function ensures the following:
1. All variables requested with type fp16 are stored as type fp32.
2. All variables requested with type fp32 are returned as type fp16.
See https://docs.nvidia.com/deeplearning/sdk/mixed-precision-training/
#training_tensorflow for more information on this strategy.
Args:
getter: custom getter
*args: arguments
**kwargs: keyword arguments
Returns:
variables with the correct dtype.
Raises:
KeyError: if "dtype" is not provided as a kwarg.
"""
requested_dtype = kwargs["dtype"]
if requested_dtype == tf.float16:
kwargs["dtype"] = tf.float32
if requested_dtype == tf.float32:
requested_dtype = tf.float16
var = getter(*args, **kwargs)
# This if statement is needed to guard the cast, because batch norm
# assigns directly to the return value of this custom getter. The cast
# makes the return value not a variable so it cannot be assigned. Batch
# norm variables are always in fp32 so this if statement is never
# triggered for them.
if var.dtype.base_dtype != requested_dtype:
var = tf.cast(var, requested_dtype)
return var |
Simulate quantization to num_bits bits, with externally-stored scale.
num_bits is the number of bits used to store each value.
noise is a float32 Tensor containing values in [0, 1).
Each value in noise should take different values across
different steps, approximating a uniform distribution over [0, 1).
In the case of replicated TPU training, noise should be identical
across replicas in order to keep the parameters identical across replicas.
The natural choice for noise would be tf.random_uniform(),
but this is not possible for TPU, since there is currently no way to seed
the different cores to produce identical values across replicas. Instead we
use noise_from_step_num() (see below).
The quantization scheme is as follows:
Compute the maximum absolute value by row (call this max_abs).
Store this either in an auxiliary variable or in an extra column.
Divide the parameters by (max_abs / (2^(num_bits-1)-1)). This gives a
float32 value in the range [-2^(num_bits-1)-1, 2^(num_bits-1)-1]
Unbiased randomized roundoff by adding noise and rounding down.
This produces a signed integer with num_bits bits which can then be stored.
Args:
x: a float32 Tensor
num_bits: an integer between 1 and 22
noise: a float Tensor broadcastable to the shape of x.
Returns:
a float32 Tensor | def simulated_quantize(x, num_bits, noise):
"""Simulate quantization to num_bits bits, with externally-stored scale.
num_bits is the number of bits used to store each value.
noise is a float32 Tensor containing values in [0, 1).
Each value in noise should take different values across
different steps, approximating a uniform distribution over [0, 1).
In the case of replicated TPU training, noise should be identical
across replicas in order to keep the parameters identical across replicas.
The natural choice for noise would be tf.random_uniform(),
but this is not possible for TPU, since there is currently no way to seed
the different cores to produce identical values across replicas. Instead we
use noise_from_step_num() (see below).
The quantization scheme is as follows:
Compute the maximum absolute value by row (call this max_abs).
Store this either in an auxiliary variable or in an extra column.
Divide the parameters by (max_abs / (2^(num_bits-1)-1)). This gives a
float32 value in the range [-2^(num_bits-1)-1, 2^(num_bits-1)-1]
Unbiased randomized roundoff by adding noise and rounding down.
This produces a signed integer with num_bits bits which can then be stored.
Args:
x: a float32 Tensor
num_bits: an integer between 1 and 22
noise: a float Tensor broadcastable to the shape of x.
Returns:
a float32 Tensor
"""
shape = x.get_shape().as_list()
if not (len(shape) >= 2 and shape[-1] > 1):
return x
max_abs = tf.reduce_max(tf.abs(x), -1, keepdims=True) + 1e-9
max_int = 2 ** (num_bits - 1) - 1
scale = max_abs / max_int
x /= scale
x = tf.floor(x + noise)
# dequantize before storing (since this is a simulation)
x *= scale
return x |
Quantization noise equal to (phi * (step_num + 1)) mod 1.0.
Not using random_uniform here due to a problem on TPU in that random seeds
are not respected, which may cause the parameters on different replicas
to go out-of-sync.
Returns:
a float32 scalar | def noise_from_step_num():
"""Quantization noise equal to (phi * (step_num + 1)) mod 1.0.
Not using random_uniform here due to a problem on TPU in that random seeds
are not respected, which may cause the parameters on different replicas
to go out-of-sync.
Returns:
a float32 scalar
"""
step = tf.to_int32(tf.train.get_or_create_global_step()) + 1
phi = ((5 ** 0.5) - 1) / 2
# Naive computation tf.mod(phi * step, 1.0) in float32 would be disastrous
# due to loss of precision when the step number gets large.
# Computation in doubles does not work on TPU, so we use this complicated
# alternative computation which does not suffer from these roundoff errors.
ret = 0.0
for i in range(30):
ret += (((phi * (2 ** i)) % 1.0) # double-precision computation in python
* tf.to_float(tf.mod(step // (2 ** i), 2)))
return tf.mod(ret, 1.0) |
Round-off x to cand1 or to cand2 in an unbiased way.
Cand1 and cand2 are the same shape as x.
For every element of x, the corresponding elements of cand1 and cand2 should
be the two closest bfloat16 values to x. Order does not matter.
cand1 and cand2 must differ from each other.
Args:
x: A float32 Tensor.
noise: A Tensor broadcastable to the shape of x containing
random uniform values in [0.0, 1.0].
cand1: A bfloat16 Tensor the same shape as x.
cand2: A bfloat16 Tensor the same shape as x.
Returns:
A bfloat16 Tensor. | def _randomized_roundoff_to_bfloat16(x, noise, cand1, cand2):
"""Round-off x to cand1 or to cand2 in an unbiased way.
Cand1 and cand2 are the same shape as x.
For every element of x, the corresponding elements of cand1 and cand2 should
be the two closest bfloat16 values to x. Order does not matter.
cand1 and cand2 must differ from each other.
Args:
x: A float32 Tensor.
noise: A Tensor broadcastable to the shape of x containing
random uniform values in [0.0, 1.0].
cand1: A bfloat16 Tensor the same shape as x.
cand2: A bfloat16 Tensor the same shape as x.
Returns:
A bfloat16 Tensor.
"""
cand1_f = tf.to_float(cand1)
cand2_f = tf.to_float(cand2)
step_size = cand2_f - cand1_f
fpart = (x - cand1_f) / step_size
ret = tf.where(tf.greater(fpart, noise), cand2, cand1)
return ret |
Convert a float32 to a bfloat16 using randomized roundoff.
Args:
x: A float32 Tensor.
noise: a float32 Tensor with values in [0, 1), broadcastable to tf.shape(x)
Returns:
A float32 Tensor. | def _to_bfloat16_unbiased(x, noise):
"""Convert a float32 to a bfloat16 using randomized roundoff.
Args:
x: A float32 Tensor.
noise: a float32 Tensor with values in [0, 1), broadcastable to tf.shape(x)
Returns:
A float32 Tensor.
"""
x_sign = tf.sign(x)
# Make sure x is positive. If it is zero, the two candidates are identical.
x = x * x_sign + 1e-30
cand1 = tf.to_bfloat16(x)
cand1_f = tf.to_float(cand1)
# This relies on the fact that for a positive bfloat16 b,
# b * 1.005 gives you the next higher bfloat16 and b*0.995 gives you the
# next lower one. Both 1.005 and 0.995 are ballpark estimation.
cand2 = tf.to_bfloat16(
tf.where(tf.greater(x, cand1_f), cand1_f * 1.005, cand1_f * 0.995))
ret = _randomized_roundoff_to_bfloat16(x, noise, cand1, cand2)
return ret * tf.to_bfloat16(x_sign) |
A custom getter that uses the encoding for bfloat16 and float32 vars.
When a bfloat16 or float32 variable is requsted, an encoded float16
varaible is created, which is then decoded and cast to a bfloat16
activation.
Args:
activation_dtype: a dtype to which to convert the decoded value.
Returns:
a function. | def custom_getter(self, activation_dtype=tf.bfloat16):
"""A custom getter that uses the encoding for bfloat16 and float32 vars.
When a bfloat16 or float32 variable is requsted, an encoded float16
varaible is created, which is then decoded and cast to a bfloat16
activation.
Args:
activation_dtype: a dtype to which to convert the decoded value.
Returns:
a function.
"""
def getter_fn(getter, *args, **kwargs):
requested_dtype = kwargs["dtype"]
if requested_dtype in (tf.bfloat16, tf.float32):
kwargs["dtype"] = tf.bfloat16
kwargs["initializer"] = _EncodingInitializer(
kwargs["initializer"], self)
ret = self._decode_with_identity_gradient(getter(*args, **kwargs))
return tf.cast(ret, activation_dtype)
return getter(*args, **kwargs)
return getter_fn |
Loads videos from files.
Args:
template: template string for listing the image files.
video_length: length of the video.
frame_shape: shape of each frame.
Returns:
dataset: the tf dataset frame by frame.
dataset_len: number of the items which is the number of image files.
Raises:
ValueError: if no files found. | def load_videos(template, video_length, frame_shape):
"""Loads videos from files.
Args:
template: template string for listing the image files.
video_length: length of the video.
frame_shape: shape of each frame.
Returns:
dataset: the tf dataset frame by frame.
dataset_len: number of the items which is the number of image files.
Raises:
ValueError: if no files found.
"""
filenames = tf.gfile.Glob(template)
if not filenames:
raise ValueError("no files found.")
filenames = sorted(filenames)
dataset_len = len(filenames)
filenames = tf.constant(filenames)
dataset = tf.data.Dataset.from_tensor_slices(filenames)
dataset = dataset.apply(tf.data.experimental.map_and_batch(
lambda filename: load_image_map_function(filename, frame_shape),
video_length, drop_remainder=True))
return dataset, dataset_len |
Compute the PSNR and SSIM.
Args:
output: 4-D Tensor, shape=(num_frames, height, width, num_channels)
target: 4-D Tensor, shape=(num_frames, height, width, num_channels)
Returns:
psnr: 1-D Tensor, shape=(num_frames,)
ssim: 1-D Tensor, shape=(num_frames,) | def psnr_and_ssim(output, target):
"""Compute the PSNR and SSIM.
Args:
output: 4-D Tensor, shape=(num_frames, height, width, num_channels)
target: 4-D Tensor, shape=(num_frames, height, width, num_channels)
Returns:
psnr: 1-D Tensor, shape=(num_frames,)
ssim: 1-D Tensor, shape=(num_frames,)
"""
output = tf.cast(output, dtype=tf.int32)
target = tf.cast(target, dtype=tf.int32)
psnr = tf.image.psnr(output, target, max_val=255)
ssim = tf.image.ssim(output, target, max_val=255)
return psnr, ssim |
Creates dataset from in-memory predictions. | def get_zipped_dataset_from_predictions(predictions):
"""Creates dataset from in-memory predictions."""
targets = stack_data_given_key(predictions, "targets")
outputs = stack_data_given_key(predictions, "outputs")
num_videos, num_steps = targets.shape[:2]
# Truncate output time-steps to match target time-steps
outputs = outputs[:, :num_steps]
targets_placeholder = tf.placeholder(targets.dtype, targets.shape)
outputs_placeholder = tf.placeholder(outputs.dtype, outputs.shape)
dataset = tf.data.Dataset.from_tensor_slices(
(targets_placeholder, outputs_placeholder))
iterator = dataset.make_initializable_iterator()
feed_dict = {targets_placeholder: targets,
outputs_placeholder: outputs}
return iterator, feed_dict, num_videos |
Computes the average of all the metric for one decoding.
Args:
iterator: dataset iterator.
feed_dict: feed dict to initialize iterator.
num_videos: number of videos.
Returns:
all_psnr: 2-D Numpy array, shape=(num_samples, num_frames)
all_ssim: 2-D Numpy array, shape=(num_samples, num_frames) | def compute_one_decoding_video_metrics(iterator, feed_dict, num_videos):
"""Computes the average of all the metric for one decoding.
Args:
iterator: dataset iterator.
feed_dict: feed dict to initialize iterator.
num_videos: number of videos.
Returns:
all_psnr: 2-D Numpy array, shape=(num_samples, num_frames)
all_ssim: 2-D Numpy array, shape=(num_samples, num_frames)
"""
output, target = iterator.get_next()
metrics = psnr_and_ssim(output, target)
with tf.Session() as sess:
sess.run(tf.local_variables_initializer())
initalizer = iterator._initializer # pylint: disable=protected-access
if initalizer is not None:
sess.run(initalizer, feed_dict=feed_dict)
all_psnr, all_ssim = [], []
for i in range(num_videos):
print("Computing video: %d" % i)
psnr_np, ssim_np = sess.run(metrics)
all_psnr.append(psnr_np)
all_ssim.append(ssim_np)
all_psnr = np.array(all_psnr)
all_ssim = np.array(all_ssim)
return all_psnr, all_ssim |
Extracts the best-decode from the metrics according to reduce_func.
Args:
metrics: 3-D numpy array, shape=(num_decodes, num_samples, num_frames)
reduce_func: callable, np.argmax or np.argmin.
Returns:
best_metrics: 2-D numpy array, shape=(num_samples, num_frames).
best_decode_ind: 1-D numpy array, shape=(num_samples,) | def reduce_to_best_decode(metrics, reduce_func):
"""Extracts the best-decode from the metrics according to reduce_func.
Args:
metrics: 3-D numpy array, shape=(num_decodes, num_samples, num_frames)
reduce_func: callable, np.argmax or np.argmin.
Returns:
best_metrics: 2-D numpy array, shape=(num_samples, num_frames).
best_decode_ind: 1-D numpy array, shape=(num_samples,)
"""
num_videos = metrics.shape[1]
# Take mean of the metric across the frames to approximate the video
# closest to the ground truth.
mean_across_frames = np.mean(metrics, axis=-1)
# For every sample, use the decode that has a maximum mean-metric.
best_decode_ind = reduce_func(mean_across_frames, axis=0)
best_metrics = metrics[best_decode_ind, np.arange(num_videos), :]
return best_metrics, best_decode_ind |
Computes statistics of metrics across multiple decodings.
Args:
all_results: dict of 3-D numpy arrays.
Each array has shape=(num_decodes, num_samples, num_frames).
Returns:
statistics: dict of 1-D numpy arrays, shape=(num_frames).
First the statistic (max/mean/std) is computed across the
decodes, then the mean is taken across num_samples.
decode_inds: dict of 1-D numpy arrays, shape=(num_samples,)
Each element represents the index of the decode corresponding
to the best statistic. | def compute_all_metrics_statistics(all_results):
"""Computes statistics of metrics across multiple decodings.
Args:
all_results: dict of 3-D numpy arrays.
Each array has shape=(num_decodes, num_samples, num_frames).
Returns:
statistics: dict of 1-D numpy arrays, shape=(num_frames).
First the statistic (max/mean/std) is computed across the
decodes, then the mean is taken across num_samples.
decode_inds: dict of 1-D numpy arrays, shape=(num_samples,)
Each element represents the index of the decode corresponding
to the best statistic.
"""
statistics = {}
decode_inds = {}
all_metrics = all_results.keys()
for key in all_metrics:
values = all_results[key]
statistics[key + "_MEAN"] = np.mean(values, axis=0)
statistics[key + "_STD"] = np.std(values, axis=0)
min_stats, min_decode_ind = reduce_to_best_decode(values, np.argmin)
statistics[key + "_MIN"] = min_stats
decode_inds[key + "_MIN_DECODE"] = min_decode_ind
max_stats, max_decode_ind = reduce_to_best_decode(values, np.argmax)
statistics[key + "_MAX"] = max_stats
decode_inds[key + "_MAX_DECODE"] = max_decode_ind
# Computes mean of each statistic across the dataset.
for key in statistics:
statistics[key] = np.mean(statistics[key], axis=0)
return statistics, decode_inds |
Computes metrics from predictions.
Args:
predictions: list of list of dicts.
outer length: num_decodes, inner_length: num_samples
decode_hparams: Decode hparams. instance of HParams.
Returns:
statistics: dict of Tensors, key being the metric with each Tensor
having the shape (num_samples, num_frames). | def compute_video_metrics_from_predictions(predictions, decode_hparams):
"""Computes metrics from predictions.
Args:
predictions: list of list of dicts.
outer length: num_decodes, inner_length: num_samples
decode_hparams: Decode hparams. instance of HParams.
Returns:
statistics: dict of Tensors, key being the metric with each Tensor
having the shape (num_samples, num_frames).
"""
all_results = {}
ssim_all_decodes, psnr_all_decodes = [], []
for single_decode in predictions:
args = get_zipped_dataset_from_predictions(single_decode)
psnr_single, ssim_single = compute_one_decoding_video_metrics(*args)
psnr_all_decodes.append(psnr_single)
ssim_all_decodes.append(ssim_single)
psnr_all_decodes = np.array(psnr_all_decodes)
ssim_all_decodes = np.array(ssim_all_decodes)
all_results.update({"PSNR": psnr_all_decodes, "SSIM": ssim_all_decodes})
return compute_all_metrics_statistics(all_results) |
Computes the average of all the metric for one decoding.
This function assumes that all the predicted and target frames
have been saved on the disk and sorting them by name will result
to consecutive frames saved in order.
Args:
output_dirs: directory with all the saved frames.
problem_name: prefix of the saved frames usually name of the problem.
video_length: length of the videos.
frame_shape: shape of each frame in HxWxC format.
Returns:
Dictionary which contains the average of each metric per frame. | def compute_video_metrics_from_png_files(
output_dirs, problem_name, video_length, frame_shape):
"""Computes the average of all the metric for one decoding.
This function assumes that all the predicted and target frames
have been saved on the disk and sorting them by name will result
to consecutive frames saved in order.
Args:
output_dirs: directory with all the saved frames.
problem_name: prefix of the saved frames usually name of the problem.
video_length: length of the videos.
frame_shape: shape of each frame in HxWxC format.
Returns:
Dictionary which contains the average of each metric per frame.
"""
ssim_all_decodes, psnr_all_decodes = [], []
for output_dir in output_dirs:
output_files, target_files = get_target_and_output_filepatterns(
output_dir, problem_name)
args = get_zipped_dataset_from_png_files(
output_files, target_files, video_length, frame_shape)
psnr_single, ssim_single = compute_one_decoding_video_metrics(*args)
psnr_all_decodes.append(psnr_single)
ssim_all_decodes.append(ssim_single)
psnr_all_decodes = np.array(psnr_all_decodes)
ssim_all_decodes = np.array(ssim_all_decodes)
all_results = {"PSNR": psnr_all_decodes, "SSIM": ssim_all_decodes}
return compute_all_metrics_statistics(all_results) |
Compute and saves the video metrics. | def compute_and_save_video_metrics(
output_dirs, problem_name, video_length, frame_shape):
"""Compute and saves the video metrics."""
statistics, all_results = compute_video_metrics_from_png_files(
output_dirs, problem_name, video_length, frame_shape)
for results, output_dir in zip(all_results, output_dirs):
save_results(results, output_dir, problem_name)
parent_dir = os.path.join(output_dirs[0], os.pardir)
final_dir = os.path.join(parent_dir, "decode")
tf.gfile.MakeDirs(parent_dir)
save_results(statistics, final_dir, problem_name) |
Swaps time and batch axis (the first two axis). | def swap_time_and_batch_axes(inputs):
"""Swaps time and batch axis (the first two axis)."""
transposed_axes = tf.concat([[1, 0], tf.range(2, tf.rank(inputs))], axis=0)
return tf.transpose(inputs, transposed_axes) |
Encode the given tensor to given image shape. | def encode_to_shape(inputs, shape, scope):
"""Encode the given tensor to given image shape."""
with tf.variable_scope(scope, reuse=tf.AUTO_REUSE):
w, h = shape[1], shape[2]
x = inputs
x = tfl.flatten(x)
x = tfl.dense(x, w * h, activation=None, name="enc_dense")
x = tf.reshape(x, (-1, w, h, 1))
return x |
Encode the given tensor to given image shape. | def decode_to_shape(inputs, shape, scope):
"""Encode the given tensor to given image shape."""
with tf.variable_scope(scope, reuse=tf.AUTO_REUSE):
x = inputs
x = tfl.flatten(x)
x = tfl.dense(x, shape[2], activation=None, name="dec_dense")
x = tf.expand_dims(x, axis=1)
return x |
Basic LSTM. | def basic_lstm(inputs, state, num_units, name=None):
"""Basic LSTM."""
input_shape = common_layers.shape_list(inputs)
# reuse parameters across time-steps.
cell = tf.nn.rnn_cell.BasicLSTMCell(
num_units, name=name, reuse=tf.AUTO_REUSE)
if state is None:
state = cell.zero_state(input_shape[0], tf.float32)
outputs, new_state = cell(inputs, state)
return outputs, new_state |
Full LSTM cell. | def lstm_cell(inputs,
state,
num_units,
use_peepholes=False,
cell_clip=0.0,
initializer=None,
num_proj=None,
num_unit_shards=None,
num_proj_shards=None,
reuse=None,
name=None):
"""Full LSTM cell."""
input_shape = common_layers.shape_list(inputs)
cell = tf.nn.rnn_cell.LSTMCell(num_units,
use_peepholes=use_peepholes,
cell_clip=cell_clip,
initializer=initializer,
num_proj=num_proj,
num_unit_shards=num_unit_shards,
num_proj_shards=num_proj_shards,
reuse=reuse,
name=name,
state_is_tuple=False)
if state is None:
state = cell.zero_state(input_shape[0], tf.float32)
outputs, new_state = cell(inputs, state)
return outputs, new_state |
2D Convolutional LSTM. | def conv_lstm_2d(inputs, state, output_channels,
kernel_size=5, name=None, spatial_dims=None):
"""2D Convolutional LSTM."""
input_shape = common_layers.shape_list(inputs)
batch_size, input_channels = input_shape[0], input_shape[-1]
if spatial_dims is None:
input_shape = input_shape[1:]
else:
input_shape = spatial_dims + [input_channels]
cell = tf.contrib.rnn.ConvLSTMCell(
2, input_shape, output_channels,
[kernel_size, kernel_size], name=name)
if state is None:
state = cell.zero_state(batch_size, tf.float32)
outputs, new_state = cell(inputs, state)
return outputs, new_state |
Sample batch with specified mix of groundtruth and generated data points.
Args:
ground_truth_x: tensor of ground-truth data points.
generated_x: tensor of generated data points.
batch_size: batch size
scheduled_sample_var: number of ground-truth examples to include in batch.
Returns:
New batch with num_ground_truth sampled from ground_truth_x and the rest
from generated_x. | def scheduled_sample_count(ground_truth_x,
generated_x,
batch_size,
scheduled_sample_var):
"""Sample batch with specified mix of groundtruth and generated data points.
Args:
ground_truth_x: tensor of ground-truth data points.
generated_x: tensor of generated data points.
batch_size: batch size
scheduled_sample_var: number of ground-truth examples to include in batch.
Returns:
New batch with num_ground_truth sampled from ground_truth_x and the rest
from generated_x.
"""
num_ground_truth = scheduled_sample_var
idx = tf.random_shuffle(tf.range(batch_size))
ground_truth_idx = tf.gather(idx, tf.range(num_ground_truth))
generated_idx = tf.gather(idx, tf.range(num_ground_truth, batch_size))
ground_truth_examps = tf.gather(ground_truth_x, ground_truth_idx)
generated_examps = tf.gather(generated_x, generated_idx)
output = tf.dynamic_stitch([ground_truth_idx, generated_idx],
[ground_truth_examps, generated_examps])
# if batch size is known set it.
if isinstance(batch_size, int):
output.set_shape([batch_size] + common_layers.shape_list(output)[1:])
return output |
Injects the additional input into the layer.
Args:
layer: layer that the input should be injected to.
inputs: inputs to be injected.
name: TF scope name.
mode: how the infor should be added to the layer:
"concat" concats as additional channels.
"multiplicative" broadcasts inputs and multiply them to the channels.
"multi_additive" broadcasts inputs and multiply and add to the channels.
Returns:
updated layer.
Raises:
ValueError: in case of unknown mode. | def inject_additional_input(layer, inputs, name, mode="concat"):
"""Injects the additional input into the layer.
Args:
layer: layer that the input should be injected to.
inputs: inputs to be injected.
name: TF scope name.
mode: how the infor should be added to the layer:
"concat" concats as additional channels.
"multiplicative" broadcasts inputs and multiply them to the channels.
"multi_additive" broadcasts inputs and multiply and add to the channels.
Returns:
updated layer.
Raises:
ValueError: in case of unknown mode.
"""
layer_shape = common_layers.shape_list(layer)
input_shape = common_layers.shape_list(inputs)
zeros_mask = tf.zeros(layer_shape, dtype=tf.float32)
if mode == "concat":
emb = encode_to_shape(inputs, layer_shape, name)
layer = tf.concat(values=[layer, emb], axis=-1)
elif mode == "multiplicative":
filters = layer_shape[-1]
input_reshaped = tf.reshape(inputs, [-1, 1, 1, input_shape[-1]])
input_mask = tf.layers.dense(input_reshaped, filters, name=name)
input_broad = input_mask + zeros_mask
layer *= input_broad
elif mode == "multi_additive":
filters = layer_shape[-1]
input_reshaped = tf.reshape(inputs, [-1, 1, 1, input_shape[-1]])
input_mul = tf.layers.dense(input_reshaped, filters, name=name + "_mul")
layer *= tf.nn.sigmoid(input_mul)
input_add = tf.layers.dense(input_reshaped, filters, name=name + "_add")
layer += input_add
else:
raise ValueError("Unknown injection mode: %s" % mode)
return layer |
Probability based scheduled sampling.
Args:
ground_truth_x: tensor of ground-truth data points.
generated_x: tensor of generated data points.
batch_size: batch size
scheduled_sample_var: probability of choosing from ground_truth.
Returns:
New batch with randomly selected data points. | def scheduled_sample_prob(ground_truth_x,
generated_x,
batch_size,
scheduled_sample_var):
"""Probability based scheduled sampling.
Args:
ground_truth_x: tensor of ground-truth data points.
generated_x: tensor of generated data points.
batch_size: batch size
scheduled_sample_var: probability of choosing from ground_truth.
Returns:
New batch with randomly selected data points.
"""
probability_threshold = scheduled_sample_var
probability_of_generated = tf.random_uniform([batch_size])
return tf.where(probability_of_generated > probability_threshold,
generated_x, ground_truth_x) |
Apply dynamic neural advection to previous image.
Args:
prev_image: previous image to be transformed.
dna_input: hidden lyaer to be used for computing DNA transformation.
dna_kernel_size: dna kernel size.
relu_shift: shift for ReLU function.
Returns:
List of images transformed by the predicted CDNA kernels. | def dna_transformation(prev_image, dna_input, dna_kernel_size, relu_shift):
"""Apply dynamic neural advection to previous image.
Args:
prev_image: previous image to be transformed.
dna_input: hidden lyaer to be used for computing DNA transformation.
dna_kernel_size: dna kernel size.
relu_shift: shift for ReLU function.
Returns:
List of images transformed by the predicted CDNA kernels.
"""
# Construct translated images.
prev_image_pad = tf.pad(prev_image, [[0, 0], [2, 2], [2, 2], [0, 0]])
image_height = int(prev_image.get_shape()[1])
image_width = int(prev_image.get_shape()[2])
inputs = []
for xkern in range(dna_kernel_size):
for ykern in range(dna_kernel_size):
inputs.append(
tf.expand_dims(
tf.slice(prev_image_pad, [0, xkern, ykern, 0],
[-1, image_height, image_width, -1]), [3]))
inputs = tf.concat(axis=3, values=inputs)
# Normalize channels to 1.
kernel = tf.nn.relu(dna_input - relu_shift) + relu_shift
kernel = tf.expand_dims(
kernel / tf.reduce_sum(kernel, [3], keep_dims=True), [4])
return tf.reduce_sum(kernel * inputs, [3], keep_dims=False) |
Apply convolutional dynamic neural advection to previous image.
Args:
prev_image: previous image to be transformed.
cdna_input: hidden lyaer to be used for computing CDNA kernels.
num_masks: number of masks and hence the number of CDNA transformations.
color_channels: the number of color channels in the images.
dna_kernel_size: dna kernel size.
relu_shift: shift for ReLU function.
Returns:
List of images transformed by the predicted CDNA kernels. | def cdna_transformation(prev_image, cdna_input, num_masks, color_channels,
dna_kernel_size, relu_shift):
"""Apply convolutional dynamic neural advection to previous image.
Args:
prev_image: previous image to be transformed.
cdna_input: hidden lyaer to be used for computing CDNA kernels.
num_masks: number of masks and hence the number of CDNA transformations.
color_channels: the number of color channels in the images.
dna_kernel_size: dna kernel size.
relu_shift: shift for ReLU function.
Returns:
List of images transformed by the predicted CDNA kernels.
"""
batch_size = tf.shape(cdna_input)[0]
height = int(prev_image.get_shape()[1])
width = int(prev_image.get_shape()[2])
# Predict kernels using linear function of last hidden layer.
cdna_kerns = tfl.dense(
cdna_input, dna_kernel_size * dna_kernel_size * num_masks,
name="cdna_params",
activation=None)
# Reshape and normalize.
cdna_kerns = tf.reshape(
cdna_kerns, [batch_size, dna_kernel_size, dna_kernel_size, 1, num_masks])
cdna_kerns = (tf.nn.relu(cdna_kerns - relu_shift) + relu_shift)
norm_factor = tf.reduce_sum(cdna_kerns, [1, 2, 3], keep_dims=True)
cdna_kerns /= norm_factor
# Treat the color channel dimension as the batch dimension since the same
# transformation is applied to each color channel.
# Treat the batch dimension as the channel dimension so that
# depthwise_conv2d can apply a different transformation to each sample.
cdna_kerns = tf.transpose(cdna_kerns, [1, 2, 0, 4, 3])
cdna_kerns = tf.reshape(
cdna_kerns, [dna_kernel_size, dna_kernel_size, batch_size, num_masks])
# Swap the batch and channel dimensions.
prev_image = tf.transpose(prev_image, [3, 1, 2, 0])
# Transform image.
transformed = tf.nn.depthwise_conv2d(
prev_image, cdna_kerns, [1, 1, 1, 1], "SAME")
# Transpose the dimensions to where they belong.
transformed = tf.reshape(
transformed, [color_channels, height, width, batch_size, num_masks])
transformed = tf.transpose(transformed, [3, 1, 2, 0, 4])
transformed = tf.unstack(transformed, axis=-1)
return transformed |
A layer of VGG network with batch norm.
Args:
inputs: image tensor
nout: number of output channels
kernel_size: size of the kernel
activation: activation function
padding: padding of the image
is_training: whether it is training mode or not
has_batchnorm: whether batchnorm is applied or not
scope: variable scope of the op
Returns:
net: output of layer | def vgg_layer(inputs,
nout,
kernel_size=3,
activation=tf.nn.leaky_relu,
padding="SAME",
is_training=True,
has_batchnorm=False,
scope=None):
"""A layer of VGG network with batch norm.
Args:
inputs: image tensor
nout: number of output channels
kernel_size: size of the kernel
activation: activation function
padding: padding of the image
is_training: whether it is training mode or not
has_batchnorm: whether batchnorm is applied or not
scope: variable scope of the op
Returns:
net: output of layer
"""
with tf.variable_scope(scope):
net = tfl.conv2d(inputs, nout, kernel_size=kernel_size, padding=padding,
activation=None, name="conv")
if has_batchnorm:
net = tfl.batch_normalization(net, training=is_training, name="bn")
net = activation(net)
return net |
Tile latent and concatenate to image across depth.
Args:
image: 4-D Tensor, (batch_size X height X width X channels)
latent: 2-D Tensor, (batch_size X latent_dims)
concat_latent: If set to False, the image is returned as is.
Returns:
concat_latent: 4-D Tensor, (batch_size X height X width X channels+1)
latent tiled and concatenated to the image across the channels. | def tile_and_concat(image, latent, concat_latent=True):
"""Tile latent and concatenate to image across depth.
Args:
image: 4-D Tensor, (batch_size X height X width X channels)
latent: 2-D Tensor, (batch_size X latent_dims)
concat_latent: If set to False, the image is returned as is.
Returns:
concat_latent: 4-D Tensor, (batch_size X height X width X channels+1)
latent tiled and concatenated to the image across the channels.
"""
if not concat_latent:
return image
image_shape = common_layers.shape_list(image)
latent_shape = common_layers.shape_list(latent)
height, width = image_shape[1], image_shape[2]
latent_dims = latent_shape[1]
height_multiples = height // latent_dims
pad = height - (height_multiples * latent_dims)
latent = tf.reshape(latent, (-1, latent_dims, 1, 1))
latent = tf.tile(latent, (1, height_multiples, width, 1))
latent = tf.pad(latent, [[0, 0], [pad // 2, pad // 2], [0, 0], [0, 0]])
return tf.concat([image, latent], axis=-1) |
Encodes numpy images into gif string.
Args:
images: A 4-D `uint8` `np.array` (or a list of 3-D images) of shape
`[time, height, width, channels]` where `channels` is 1 or 3.
fps: frames per second of the animation
Returns:
The encoded gif string.
Raises:
IOError: If the ffmpeg command returns an error. | def _encode_gif(images, fps):
"""Encodes numpy images into gif string.
Args:
images: A 4-D `uint8` `np.array` (or a list of 3-D images) of shape
`[time, height, width, channels]` where `channels` is 1 or 3.
fps: frames per second of the animation
Returns:
The encoded gif string.
Raises:
IOError: If the ffmpeg command returns an error.
"""
writer = WholeVideoWriter(fps)
writer.write_multi(images)
return writer.finish() |
Tries to encode images with ffmpeg to check if it works. | def ffmpeg_works():
"""Tries to encode images with ffmpeg to check if it works."""
images = np.zeros((2, 32, 32, 3), dtype=np.uint8)
try:
_encode_gif(images, 2)
return True
except (IOError, OSError):
return False |
Outputs a `Summary` protocol buffer with gif animations.
Args:
tag: Name of the summary.
images: A 5-D `uint8` `np.array` of shape `[batch_size, time, height, width,
channels]` where `channels` is 1 or 3.
max_outputs: Max number of batch elements to generate gifs for.
fps: frames per second of the animation.
return_summary_value: If set to True, return a list of tf.Summary.Value
objects in addition to the protocol buffer.
Returns:
The serialized `Summary` protocol buffer.
Raises:
ValueError: If `images` is not a 5-D `uint8` array with 1 or 3 channels. | def py_gif_summary(tag, images, max_outputs, fps, return_summary_value=False):
"""Outputs a `Summary` protocol buffer with gif animations.
Args:
tag: Name of the summary.
images: A 5-D `uint8` `np.array` of shape `[batch_size, time, height, width,
channels]` where `channels` is 1 or 3.
max_outputs: Max number of batch elements to generate gifs for.
fps: frames per second of the animation.
return_summary_value: If set to True, return a list of tf.Summary.Value
objects in addition to the protocol buffer.
Returns:
The serialized `Summary` protocol buffer.
Raises:
ValueError: If `images` is not a 5-D `uint8` array with 1 or 3 channels.
"""
images = np.asarray(images)
if images.dtype != np.uint8:
raise ValueError("Tensor must have dtype uint8 for gif summary.")
if images.ndim != 5:
raise ValueError("Tensor must be 5-D for gif summary.")
batch_size, _, height, width, channels = images.shape
if channels not in (1, 3):
raise ValueError("Tensors must have 1 or 3 channels for gif summary.")
summ = tf.Summary()
all_summ_values = []
num_outputs = min(batch_size, max_outputs)
for i in range(num_outputs):
image_summ = tf.Summary.Image()
image_summ.height = height
image_summ.width = width
image_summ.colorspace = channels # 1: grayscale, 3: RGB
try:
image_summ.encoded_image_string = _encode_gif(images[i], fps)
except (IOError, OSError) as e:
tf.logging.warning(
"Unable to encode images to a gif string because either ffmpeg is "
"not installed or ffmpeg returned an error: %s. Falling back to an "
"image summary of the first frame in the sequence.", e)
try:
from PIL import Image # pylint: disable=g-import-not-at-top
import io # pylint: disable=g-import-not-at-top
with io.BytesIO() as output:
Image.fromarray(images[i][0]).save(output, "PNG")
image_summ.encoded_image_string = output.getvalue()
except ImportError as e:
tf.logging.warning(
"Gif summaries requires ffmpeg or PIL to be installed: %s", e)
image_summ.encoded_image_string = ""
if num_outputs == 1:
summ_tag = "{}/gif".format(tag)
else:
summ_tag = "{}/gif/{}".format(tag, i)
curr_summ_value = tf.Summary.Value(tag=summ_tag, image=image_summ)
all_summ_values.append(curr_summ_value)
summ.value.add(tag=summ_tag, image=image_summ)
summ_str = summ.SerializeToString()
if return_summary_value:
return all_summ_values, summ_str
return summ_str |
Outputs a `Summary` protocol buffer with gif animations.
Args:
name: Name of the summary.
tensor: A 5-D `uint8` `Tensor` of shape `[batch_size, time, height, width,
channels]` where `channels` is 1 or 3.
max_outputs: Max number of batch elements to generate gifs for.
fps: frames per second of the animation
collections: Optional list of tf.GraphKeys. The collections to add the
summary to. Defaults to [tf.GraphKeys.SUMMARIES]
family: Optional; if provided, used as the prefix of the summary tag name,
which controls the tab name used for display on Tensorboard.
Returns:
A scalar `Tensor` of type `string`. The serialized `Summary` protocol
buffer.
Raises:
ValueError: if the given tensor has the wrong shape. | def gif_summary(name, tensor, max_outputs=3, fps=10, collections=None,
family=None):
"""Outputs a `Summary` protocol buffer with gif animations.
Args:
name: Name of the summary.
tensor: A 5-D `uint8` `Tensor` of shape `[batch_size, time, height, width,
channels]` where `channels` is 1 or 3.
max_outputs: Max number of batch elements to generate gifs for.
fps: frames per second of the animation
collections: Optional list of tf.GraphKeys. The collections to add the
summary to. Defaults to [tf.GraphKeys.SUMMARIES]
family: Optional; if provided, used as the prefix of the summary tag name,
which controls the tab name used for display on Tensorboard.
Returns:
A scalar `Tensor` of type `string`. The serialized `Summary` protocol
buffer.
Raises:
ValueError: if the given tensor has the wrong shape.
"""
tensor = tf.convert_to_tensor(tensor)
if len(tensor.get_shape()) != 5:
raise ValueError("Assuming videos given as tensors in the format "
"[batch, time, height, width, channels] but got one "
"of shape: %s" % str(tensor.get_shape()))
tensor = tf.cast(tensor, tf.uint8)
if distribute_summary_op_util.skip_summary():
return tf.constant("")
with summary_op_util.summary_scope(
name, family, values=[tensor]) as (tag, scope):
val = tf.py_func(
py_gif_summary,
[tag, tensor, max_outputs, fps],
tf.string,
stateful=False,
name=scope)
summary_op_util.collect(val, collections, [tf.GraphKeys.SUMMARIES])
return val |
Builds convolutional latent tower for stochastic model.
At training time this tower generates a latent distribution (mean and std)
conditioned on the entire video. This latent variable will be fed to the
main tower as an extra variable to be used for future frames prediction.
At inference time, the tower is disabled and only returns latents sampled
from N(0,1).
If the multi_latent flag is on, a different latent for every timestep would
be generated.
Args:
images: tensor of ground truth image sequences
time_axis: the time axis in images tensor
latent_channels: number of latent channels
min_logvar: minimum value for log_var
is_training: whether or not it is training mode
random_latent: whether or not generate random latents
tiny_mode: whether or not it is tiny_mode. tiny_mode sets the number
of conv channels to 1 at each layer. useful for testing the
integration tests.
small_mode: whether or not it is small_mode. small mode is the same model
with less conv and lstm layers and also lower number of channels.
suitable for videos with less complexity and testing.
Returns:
latent_mean: predicted latent mean
latent_logvar: predicted latent log variance | def conv_latent_tower(images, time_axis, latent_channels=1, min_logvar=-5,
is_training=False, random_latent=False,
tiny_mode=False, small_mode=False):
"""Builds convolutional latent tower for stochastic model.
At training time this tower generates a latent distribution (mean and std)
conditioned on the entire video. This latent variable will be fed to the
main tower as an extra variable to be used for future frames prediction.
At inference time, the tower is disabled and only returns latents sampled
from N(0,1).
If the multi_latent flag is on, a different latent for every timestep would
be generated.
Args:
images: tensor of ground truth image sequences
time_axis: the time axis in images tensor
latent_channels: number of latent channels
min_logvar: minimum value for log_var
is_training: whether or not it is training mode
random_latent: whether or not generate random latents
tiny_mode: whether or not it is tiny_mode. tiny_mode sets the number
of conv channels to 1 at each layer. useful for testing the
integration tests.
small_mode: whether or not it is small_mode. small mode is the same model
with less conv and lstm layers and also lower number of channels.
suitable for videos with less complexity and testing.
Returns:
latent_mean: predicted latent mean
latent_logvar: predicted latent log variance
"""
conv_size = tinyify([32, 64, 64], tiny_mode, small_mode)
with tf.variable_scope("latent", reuse=tf.AUTO_REUSE):
images = tf.to_float(images)
images = tf.unstack(images, axis=time_axis)
images = tf.concat(images, axis=3)
x = images
x = common_layers.make_even_size(x)
x = tfl.conv2d(x, conv_size[0], [3, 3], strides=(2, 2),
padding="SAME", activation=tf.nn.relu, name="latent_conv1")
x = tfcl.layer_norm(x)
if not small_mode:
x = tfl.conv2d(x, conv_size[1], [3, 3], strides=(2, 2),
padding="SAME", activation=tf.nn.relu, name="latent_conv2")
x = tfcl.layer_norm(x)
x = tfl.conv2d(x, conv_size[2], [3, 3], strides=(1, 1),
padding="SAME", activation=tf.nn.relu, name="latent_conv3")
x = tfcl.layer_norm(x)
nc = latent_channels
mean = tfl.conv2d(x, nc, [3, 3], strides=(2, 2),
padding="SAME", activation=None, name="latent_mean")
logv = tfl.conv2d(x, nc, [3, 3], strides=(2, 2),
padding="SAME", activation=tf.nn.relu, name="latent_std")
logvar = logv + min_logvar
# No latent tower at inference time, just standard gaussian.
if not is_training:
return tf.zeros_like(mean), tf.zeros_like(logvar)
# No latent in the first phase
ret_mean, ret_logvar = tf.cond(
random_latent,
lambda: (tf.zeros_like(mean), tf.zeros_like(logvar)),
lambda: (mean, logvar))
return ret_mean, ret_logvar |
Get KL multiplier (beta) based on the schedule. | def beta_schedule(schedule, global_step, final_beta, decay_start, decay_end):
"""Get KL multiplier (beta) based on the schedule."""
if decay_start > decay_end:
raise ValueError("decay_end is smaller than decay_end.")
# Since some of the TF schedules do not support incrementing a value,
# in all of the schedules, we anneal the beta from final_beta to zero
# and then reverse it at the bottom.
if schedule == "constant":
decayed_value = 0.0
elif schedule == "linear":
decayed_value = tf.train.polynomial_decay(
learning_rate=final_beta,
global_step=global_step - decay_start,
decay_steps=decay_end - decay_start,
end_learning_rate=0.0)
elif schedule == "noisy_linear_cosine_decay":
decayed_value = tf.train.noisy_linear_cosine_decay(
learning_rate=final_beta,
global_step=global_step - decay_start,
decay_steps=decay_end - decay_start)
# TODO(mechcoder): Add log_annealing schedule.
else:
raise ValueError("Unknown beta schedule.")
increased_value = final_beta - decayed_value
increased_value = tf.maximum(0.0, increased_value)
beta = tf.case(
pred_fn_pairs={
tf.less(global_step, decay_start): lambda: 0.0,
tf.greater(global_step, decay_end): lambda: final_beta},
default=lambda: increased_value)
return beta |
For every video, extract a random consecutive patch of num_frames.
Args:
videos: 5-D Tensor, (NTHWC)
num_frames: Integer, if -1 then the entire video is returned.
Returns:
video_patch: 5-D Tensor, (NTHWC) with T = num_frames.
Raises:
ValueError: If num_frames is greater than the number of total frames in
the video. | def extract_random_video_patch(videos, num_frames=-1):
"""For every video, extract a random consecutive patch of num_frames.
Args:
videos: 5-D Tensor, (NTHWC)
num_frames: Integer, if -1 then the entire video is returned.
Returns:
video_patch: 5-D Tensor, (NTHWC) with T = num_frames.
Raises:
ValueError: If num_frames is greater than the number of total frames in
the video.
"""
if num_frames == -1:
return videos
batch_size, num_total_frames, h, w, c = common_layers.shape_list(videos)
if num_total_frames < num_frames:
raise ValueError("Expected num_frames <= %d, got %d" %
(num_total_frames, num_frames))
# Randomly choose start_inds for each video.
frame_start = tf.random_uniform(
shape=(batch_size,), minval=0, maxval=num_total_frames - num_frames + 1,
dtype=tf.int32)
# [start[0], start[0] + 1, ... start[0] + num_frames - 1] + ...
# [start[batch_size-1], ... start[batch_size-1] + num_frames - 1]
range_inds = tf.expand_dims(tf.range(num_frames), axis=0)
frame_inds = range_inds + tf.expand_dims(frame_start, axis=1)
frame_inds = tf.reshape(frame_inds, [-1])
# [0]*num_frames + [1]*num_frames + ... [batch_size-1]*num_frames
batch_inds = tf.expand_dims(tf.range(batch_size), axis=1)
batch_inds = tf.tile(batch_inds, [1, num_frames])
batch_inds = tf.reshape(batch_inds, [-1])
gather_inds = tf.stack((batch_inds, frame_inds), axis=1)
video_patches = tf.gather_nd(videos, gather_inds)
return tf.reshape(video_patches, (batch_size, num_frames, h, w, c)) |
Writes multiple video frames. | def write_multi(self, frames, encoded_frames=None):
"""Writes multiple video frames."""
if encoded_frames is None:
# Infinite iterator.
encoded_frames = iter(lambda: None, 1)
for (frame, encoded_frame) in zip(frames, encoded_frames):
self.write(frame, encoded_frame) |
Initializes ffmpeg to write frames. | def __init_ffmpeg(self, image_shape):
"""Initializes ffmpeg to write frames."""
import itertools # pylint: disable=g-import-not-at-top
from subprocess import Popen, PIPE # pylint: disable=g-import-not-at-top,g-multiple-import,g-importing-member
ffmpeg = "ffmpeg"
height, width, channels = image_shape
self.cmd = [
ffmpeg, "-y",
"-f", "rawvideo",
"-vcodec", "rawvideo",
"-r", "%.02f" % self.fps,
"-s", "%dx%d" % (width, height),
"-pix_fmt", {1: "gray", 3: "rgb24"}[channels],
"-i", "-",
"-filter_complex", "[0:v]split[x][z];[x]fifo[w];[z]palettegen,fifo[y];"
"[w][y]paletteuse,fifo",
"-r", "%.02f" % self.fps,
"-f", self.file_format,
"-qscale", "0",
"-"
]
self.proc = Popen(
self.cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE, bufsize=-1
)
(self._out_thread, self._err_thread) = itertools.starmap(
self._start_reader_thread, [
(self.proc.stdout, self._out_chunks),
(self.proc.stderr, self._err_chunks)
]
) |
Starts a thread for reading output from FFMPEG.
The thread reads consecutive chunks from the stream and saves them in
the given list.
Args:
stream: output stream of the FFMPEG process.
chunks: list to save output chunks to.
Returns:
Thread | def _start_reader_thread(self, stream, chunks):
"""Starts a thread for reading output from FFMPEG.
The thread reads consecutive chunks from the stream and saves them in
the given list.
Args:
stream: output stream of the FFMPEG process.
chunks: list to save output chunks to.
Returns:
Thread
"""
import io # pylint: disable=g-import-not-at-top
import threading # pylint: disable=g-import-not-at-top
def target():
while True:
chunk = stream.read(io.DEFAULT_BUFFER_SIZE)
if not chunk:
break
chunks.append(chunk)
thread = threading.Thread(target=target)
thread.start()
return thread |
Finishes transconding and returns the video.
Returns:
bytes
Raises:
IOError: in case of transcoding error. | def finish(self):
"""Finishes transconding and returns the video.
Returns:
bytes
Raises:
IOError: in case of transcoding error.
"""
if self.proc is None:
return None
self.proc.stdin.close()
for thread in (self._out_thread, self._err_thread):
thread.join()
(out, err) = [
b"".join(chunks) for chunks in (self._out_chunks, self._err_chunks)
]
self.proc.stdout.close()
self.proc.stderr.close()
if self.proc.returncode:
err = "\n".join([" ".join(self.cmd), err.decode("utf8")])
raise IOError(err)
del self.proc
self.proc = None
return out |
Validates flags are set to acceptable values. | def validate_flags():
"""Validates flags are set to acceptable values."""
if FLAGS.cloud_mlengine_model_name:
assert not FLAGS.server
assert not FLAGS.servable_name
else:
assert FLAGS.server
assert FLAGS.servable_name |
Returns a request function. | def make_request_fn():
"""Returns a request function."""
if FLAGS.cloud_mlengine_model_name:
request_fn = serving_utils.make_cloud_mlengine_request_fn(
credentials=GoogleCredentials.get_application_default(),
model_name=FLAGS.cloud_mlengine_model_name,
version=FLAGS.cloud_mlengine_model_version)
else:
request_fn = serving_utils.make_grpc_request_fn(
servable_name=FLAGS.servable_name,
server=FLAGS.server,
timeout_secs=FLAGS.timeout_secs)
return request_fn |
Convnet that encodes inputs into mean and std of a gaussian.
Args:
inputs: 5-D Tensor, shape (batch_size, num_frames, width, height, channels)
n_layers: Number of layers.
Returns:
z_mu: Mean of the latent gaussians.
z_log_var: log(var) of the latent gaussians.
Raises:
ValueError: If inputs is not a 5-D tensor or not float32. | def encoder(self, inputs, n_layers=3):
"""Convnet that encodes inputs into mean and std of a gaussian.
Args:
inputs: 5-D Tensor, shape (batch_size, num_frames, width, height, channels)
n_layers: Number of layers.
Returns:
z_mu: Mean of the latent gaussians.
z_log_var: log(var) of the latent gaussians.
Raises:
ValueError: If inputs is not a 5-D tensor or not float32.
"""
latent_dims = self.hparams.z_dim
shape_as_list = inputs.shape.as_list()
if len(shape_as_list) != 5:
raise ValueError("Expected inputs to be a 5-D, got %d" %
len(shape_as_list))
if inputs.dtype != tf.float32:
raise ValueError("Expected dtype tf.float32, got %s" % inputs.dtype)
# Flatten (N,T,W,H,C) into (NT,W,H,C)
batch_size, _ = shape_as_list[:2]
inputs = tf.reshape(inputs, [-1] + list(inputs.shape)[2:])
n_filters = 64
rectified = None
# Applies 3 layer conv-net with padding, instance normalization
# and leaky relu as per the encoder in
# https://github.com/alexlee-gk/video_prediction
padding = [[0, 0], [1, 1], [1, 1], [0, 0]]
for i in range(n_layers):
with tf.variable_scope("layer_%d" % (i + 1)):
n_filters *= 2**i
if i:
padded = tf.pad(rectified, padding)
else:
padded = tf.pad(inputs, padding)
convolved = tf.layers.conv2d(padded, filters=n_filters, kernel_size=4,
strides=2, padding="VALID")
normalized = tf.contrib.layers.instance_norm(convolved)
rectified = tf.nn.leaky_relu(normalized, alpha=0.2)
# Mean pooling across all spatial dimensions.
pooled = tf.nn.avg_pool(
rectified, [1] + rectified.shape[1:3].as_list() + [1],
strides=[1, 1, 1, 1], padding="VALID")
squeezed = tf.squeeze(pooled, [1, 2])
# Down-project and output the mean and log of the standard deviation of
# the latents.
with tf.variable_scope("z_mu"):
z_mu = tf.layers.dense(squeezed, latent_dims)
with tf.variable_scope("z_log_sigma_sq"):
z_log_var = tf.layers.dense(squeezed, latent_dims)
z_log_var = tf.clip_by_value(z_log_var, -10, 10)
# Reshape to (batch_size X num_frames X latent_dims)
z_mu = tf.reshape(z_mu, (batch_size, -1, latent_dims))
z_log_var = tf.reshape(
z_log_var, (batch_size, -1, latent_dims))
return z_mu, z_log_var |
Get expected fully connected shape after a series of convolutions. | def get_fc_dimensions(self, strides, kernel_sizes):
"""Get expected fully connected shape after a series of convolutions."""
output_height, output_width, _ = self.hparams.problem.frame_shape
output_steps = self.hparams.video_num_target_frames
output_shape = np.array([output_steps, output_height, output_width])
for curr_stride, kernel_size in zip(strides, kernel_sizes):
output_shape = self.expected_output_shape(
output_shape, np.array(curr_stride), 1, kernel_size)
return np.prod(output_shape) * self.hparams.num_discriminator_filters * 8 |
3-D SNGAN discriminator.
Args:
frames: a list of batch-major tensors indexed by time.
Returns:
logits: 1-D Tensor with shape=batch_size.
Positive logits imply that the discriminator thinks that it
belongs to the true class. | def discriminator(self, frames):
"""3-D SNGAN discriminator.
Args:
frames: a list of batch-major tensors indexed by time.
Returns:
logits: 1-D Tensor with shape=batch_size.
Positive logits imply that the discriminator thinks that it
belongs to the true class.
"""
ndf = self.hparams.num_discriminator_filters
frames = tf.stack(frames)
# Switch from time-major axis to batch-major axis.
frames = common_video.swap_time_and_batch_axes(frames)
# 3-D Conv-net mapping inputs to activations.
num_outputs = [ndf, ndf*2, ndf*2, ndf*4, ndf*4, ndf*8, ndf*8]
kernel_sizes = [3, 4, 3, 4, 3, 4, 3]
strides = [[1, 1, 1], [1, 2, 2], [1, 1, 1], [1, 2, 2], [1, 1, 1],
[2, 2, 2], [1, 1, 1]]
names = ["video_sn_conv0_0", "video_sn_conv0_1", "video_sn_conv1_0",
"video_sn_conv1_1", "video_sn_conv2_0", "video_sn_conv2_1",
"video_sn_conv3_0"]
iterable = zip(num_outputs, kernel_sizes, strides, names)
activations = frames
for num_filters, kernel_size, stride, name in iterable:
activations = self.pad_conv3d_lrelu(activations, num_filters, kernel_size,
stride, name)
num_fc_dimensions = self.get_fc_dimensions(strides, kernel_sizes)
activations = tf.reshape(activations, (-1, num_fc_dimensions))
return tf.squeeze(tf.layers.dense(activations, 1)) |
Performs the discriminator step in computing the GAN loss.
Applies stop-gradient to the generated frames while computing the
discriminator loss to make sure that the gradients are not back-propagated
to the generator. This makes sure that only the discriminator is updated.
Args:
true_frames: True outputs
gen_frames: Generated frames.
Returns:
d_loss: Loss component due to the discriminator. | def d_step(self, true_frames, gen_frames):
"""Performs the discriminator step in computing the GAN loss.
Applies stop-gradient to the generated frames while computing the
discriminator loss to make sure that the gradients are not back-propagated
to the generator. This makes sure that only the discriminator is updated.
Args:
true_frames: True outputs
gen_frames: Generated frames.
Returns:
d_loss: Loss component due to the discriminator.
"""
hparam_to_disc_loss = {
"least_squares": gan_losses.least_squares_discriminator_loss,
"cross_entropy": gan_losses.modified_discriminator_loss,
"wasserstein": gan_losses.wasserstein_discriminator_loss}
# Concat across batch-axis.
_, batch_size, _, _, _ = common_layers.shape_list(true_frames)
all_frames = tf.concat(
[true_frames, tf.stop_gradient(gen_frames)], axis=1)
all_logits = self.discriminator(all_frames)
true_logits, fake_logits_stop = \
all_logits[:batch_size], all_logits[batch_size:]
mean_true_logits = tf.reduce_mean(true_logits)
tf.summary.scalar("mean_true_logits", mean_true_logits)
mean_fake_logits_stop = tf.reduce_mean(fake_logits_stop)
tf.summary.scalar("mean_fake_logits_stop", mean_fake_logits_stop)
discriminator_loss_func = hparam_to_disc_loss[self.hparams.gan_loss]
gan_d_loss = discriminator_loss_func(
discriminator_real_outputs=true_logits,
discriminator_gen_outputs=fake_logits_stop,
add_summaries=True)
return gan_d_loss, true_logits, fake_logits_stop |
Performs the generator step in computing the GAN loss.
Args:
gen_frames: Generated frames
fake_logits_stop: Logits corresponding to the generated frames as per
the discriminator. Assumed to have a stop-gradient term.
Returns:
gan_g_loss_pos_d: Loss.
gan_g_loss_neg_d: -gan_g_loss_pos_d but with a stop gradient on generator. | def g_step(self, gen_frames, fake_logits_stop):
"""Performs the generator step in computing the GAN loss.
Args:
gen_frames: Generated frames
fake_logits_stop: Logits corresponding to the generated frames as per
the discriminator. Assumed to have a stop-gradient term.
Returns:
gan_g_loss_pos_d: Loss.
gan_g_loss_neg_d: -gan_g_loss_pos_d but with a stop gradient on generator.
"""
hparam_to_gen_loss = {
"least_squares": gan_losses.least_squares_generator_loss,
"cross_entropy": gan_losses.modified_generator_loss,
"wasserstein": gan_losses.wasserstein_generator_loss
}
fake_logits = self.discriminator(gen_frames)
mean_fake_logits = tf.reduce_mean(fake_logits)
tf.summary.scalar("mean_fake_logits", mean_fake_logits)
# Generator loss.
# Using gan_g_loss_pos_d updates the discriminator as well.
# To avoid this add gan_g_loss_neg_d = -gan_g_loss_pos_d
# but with stop gradient on the generator.
# This makes sure that the net gradient on the discriminator is zero and
# net-gradient on the generator is just due to the gan_g_loss_pos_d.
generator_loss_func = hparam_to_gen_loss[self.hparams.gan_loss]
gan_g_loss_pos_d = generator_loss_func(
discriminator_gen_outputs=fake_logits, add_summaries=True)
gan_g_loss_neg_d = -generator_loss_func(
discriminator_gen_outputs=fake_logits_stop, add_summaries=True)
return gan_g_loss_pos_d, gan_g_loss_neg_d |
Get the discriminator + generator loss at every step.
This performs an 1:1 update of the discriminator and generator at every
step.
Args:
true_frames: 5-D Tensor of shape (num_steps, batch_size, H, W, C)
Assumed to be ground truth.
gen_frames: 5-D Tensor of shape (num_steps, batch_size, H, W, C)
Assumed to be fake.
name: discriminator scope.
Returns:
loss: 0-D Tensor, with d_loss + g_loss | def get_gan_loss(self, true_frames, gen_frames, name):
"""Get the discriminator + generator loss at every step.
This performs an 1:1 update of the discriminator and generator at every
step.
Args:
true_frames: 5-D Tensor of shape (num_steps, batch_size, H, W, C)
Assumed to be ground truth.
gen_frames: 5-D Tensor of shape (num_steps, batch_size, H, W, C)
Assumed to be fake.
name: discriminator scope.
Returns:
loss: 0-D Tensor, with d_loss + g_loss
"""
# D - STEP
with tf.variable_scope("%s_discriminator" % name, reuse=tf.AUTO_REUSE):
gan_d_loss, _, fake_logits_stop = self.d_step(
true_frames, gen_frames)
# G - STEP
with tf.variable_scope("%s_discriminator" % name, reuse=True):
gan_g_loss_pos_d, gan_g_loss_neg_d = self.g_step(
gen_frames, fake_logits_stop)
gan_g_loss = gan_g_loss_pos_d + gan_g_loss_neg_d
tf.summary.scalar("gan_loss_%s" % name, gan_g_loss_pos_d + gan_d_loss)
if self.hparams.gan_optimization == "joint":
gan_loss = gan_g_loss + gan_d_loss
else:
curr_step = self.get_iteration_num()
gan_loss = tf.cond(
tf.logical_not(curr_step % 2 == 0), lambda: gan_g_loss,
lambda: gan_d_loss)
return gan_loss |
Gets extra loss from VAE and GAN. | def get_extra_loss(self, latent_means=None, latent_stds=None,
true_frames=None, gen_frames=None):
"""Gets extra loss from VAE and GAN."""
if not self.is_training:
return 0.0
vae_loss, d_vae_loss, d_gan_loss = 0.0, 0.0, 0.0
# Use sv2p's KL divergence computation.
if self.hparams.use_vae:
vae_loss = super(NextFrameSavpBase, self).get_extra_loss(
latent_means=latent_means, latent_stds=latent_stds)
if self.hparams.use_gan:
# Strip out the first context_frames for the true_frames
# Strip out the first context_frames - 1 for the gen_frames
context_frames = self.hparams.video_num_input_frames
true_frames = tf.stack(
tf.unstack(true_frames, axis=0)[context_frames:])
# discriminator for VAE.
if self.hparams.use_vae:
gen_enc_frames = tf.stack(
tf.unstack(gen_frames, axis=0)[context_frames-1:])
d_vae_loss = self.get_gan_loss(true_frames, gen_enc_frames, name="vae")
# discriminator for GAN.
gen_prior_frames = tf.stack(
tf.unstack(self.gen_prior_video, axis=0)[context_frames-1:])
d_gan_loss = self.get_gan_loss(true_frames, gen_prior_frames, name="gan")
return (
vae_loss + self.hparams.gan_loss_multiplier * d_gan_loss +
self.hparams.gan_vae_loss_multiplier * d_vae_loss) |
Pad, apply 3-D convolution and leaky relu. | def pad_conv3d_lrelu(self, activations, n_filters, kernel_size, strides,
scope):
"""Pad, apply 3-D convolution and leaky relu."""
padding = [[0, 0], [1, 1], [1, 1], [1, 1], [0, 0]]
# tf.nn.conv3d accepts a list of 5 values for strides
# with first and last value equal to 1
if isinstance(strides, numbers.Integral):
strides = [strides] * 3
strides = [1] + strides + [1]
# Filter_shape = [K, K, K, num_input, num_output]
filter_shape = (
[kernel_size]*3 + activations.shape[-1:].as_list() + [n_filters])
with tf.variable_scope(scope, reuse=tf.AUTO_REUSE):
conv_filter = tf.get_variable(
"conv_filter", shape=filter_shape,
initializer=tf.truncated_normal_initializer(stddev=0.02))
if self.hparams.use_spectral_norm:
conv_filter, assign_op = common_layers.apply_spectral_norm(conv_filter)
if self.is_training:
tf.add_to_collection(tf.GraphKeys.UPDATE_OPS, assign_op)
padded = tf.pad(activations, padding)
convolved = tf.nn.conv3d(
padded, conv_filter, strides=strides, padding="VALID")
rectified = tf.nn.leaky_relu(convolved, alpha=0.2)
return rectified |
Weight-level magnitude pruning. | def weight(w, sparsity):
"""Weight-level magnitude pruning."""
w_shape = common_layers.shape_list(w)
k = int(np.prod(w_shape[:-1]))
count = tf.to_int32(k * sparsity)
mask = common_layers.weight_targeting(w, count)
return (1 - mask) * w |
Unit-level magnitude pruning. | def unit(w, sparsity):
"""Unit-level magnitude pruning."""
w_shape = common_layers.shape_list(w)
count = tf.to_int32(w_shape[-1] * sparsity)
mask = common_layers.unit_targeting(w, count)
return (1 - mask) * w |
Prune the weights of a model and evaluate. | def sparsify(sess, eval_model, pruning_strategy, pruning_params):
"""Prune the weights of a model and evaluate."""
weights = tf.trainable_variables()
def should_prune(name):
"""Whether to prune a weight or not."""
in_whitelist = not pruning_params.white_list or any(
e in name for e in pruning_params.white_list)
in_blacklist = any(e in name for e in pruning_params.black_list)
if pruning_params.white_list and not in_whitelist:
return False
elif in_blacklist:
return False
return True
weights = [w for w in weights if should_prune(w.name)]
tf.logging.info("Pruning weights: %s" % weights)
unpruned_weights = sess.run(weights)
reset_op = tf.no_op()
for w, ow in zip(weights, unpruned_weights):
op = tf.assign(w, ow)
reset_op = tf.group(reset_op, op)
for sparsity in pruning_params.sparsities:
set_weights_op = tf.no_op()
for w in weights:
op = tf.assign(w, pruning_strategy(w, sparsity))
set_weights_op = tf.group(set_weights_op, op)
sess.run(set_weights_op)
acc = eval_model()
tf.logging.info("\tPruning to sparsity = %f: acc = %f" % (sparsity, acc))
sess.run(reset_op) |
Loads the configuration. | def load_config(self):
"""Loads the configuration."""
config = dict([(key, value) for key, value in iteritems(self.options)
if key in self.cfg.settings and value is not None])
for key, value in iteritems(config):
self.cfg.set(key.lower(), value) |
Set of hyperparameters. | def ppo_base_v1():
"""Set of hyperparameters."""
hparams = common_hparams.basic_params1()
hparams.learning_rate_schedule = "constant"
hparams.learning_rate_constant = 1e-4
hparams.clip_grad_norm = 0.5
hparams.weight_decay = 0
# If set, extends the LR warmup to all epochs except the final one.
hparams.add_hparam("lr_decay_in_final_epoch", False)
hparams.add_hparam("init_mean_factor", 0.1)
hparams.add_hparam("init_logstd", 0.1)
hparams.add_hparam("policy_layers", (100, 100))
hparams.add_hparam("value_layers", (100, 100))
hparams.add_hparam("clipping_coef", 0.2)
hparams.add_hparam("gae_gamma", 0.99)
hparams.add_hparam("gae_lambda", 0.95)
hparams.add_hparam("entropy_loss_coef", 0.01)
hparams.add_hparam("value_loss_coef", 1)
hparams.add_hparam("optimization_epochs", 15)
hparams.add_hparam("epoch_length", 200)
hparams.add_hparam("epochs_num", 2000)
hparams.add_hparam("eval_every_epochs", 10)
hparams.add_hparam("save_models_every_epochs", 30)
hparams.add_hparam("optimization_batch_size", 50)
hparams.add_hparam("intrinsic_reward_scale", 0.)
hparams.add_hparam("logits_clip", 0.0)
hparams.add_hparam("dropout_ppo", 0.1)
hparams.add_hparam("effective_num_agents", None)
# TODO(afrozm): Clean this up, this is used in PPO learner to get modalities.
hparams.add_hparam("policy_problem_name", "dummy_policy_problem")
return hparams |
Pong base parameters. | def ppo_atari_base():
"""Pong base parameters."""
hparams = ppo_discrete_action_base()
hparams.learning_rate_constant = 1e-4
hparams.epoch_length = 200
hparams.gae_gamma = 0.985
hparams.gae_lambda = 0.985
hparams.entropy_loss_coef = 0.003
hparams.value_loss_coef = 1
hparams.optimization_epochs = 3
hparams.epochs_num = 1000
hparams.policy_network = "feed_forward_cnn_small_categorical_policy"
hparams.clipping_coef = 0.2
hparams.optimization_batch_size = 20
hparams.clip_grad_norm = 0.5
return hparams |
Parameters based on the original PPO paper. | def ppo_original_params():
"""Parameters based on the original PPO paper."""
hparams = ppo_atari_base()
hparams.learning_rate_constant = 2.5e-4
hparams.gae_gamma = 0.99
hparams.gae_lambda = 0.95
hparams.clipping_coef = 0.1
hparams.value_loss_coef = 1
hparams.entropy_loss_coef = 0.01
hparams.eval_every_epochs = 200
hparams.dropout_ppo = 0.1
# The parameters below are modified to accommodate short epoch_length (which
# is needed for model based rollouts).
hparams.epoch_length = 50
hparams.optimization_batch_size = 20
return hparams |
Atari parameters with world model as policy. | def ppo_original_world_model():
"""Atari parameters with world model as policy."""
hparams = ppo_original_params()
hparams.policy_network = "next_frame_basic_deterministic"
hparams_keys = hparams.values().keys()
video_hparams = basic_deterministic_params.next_frame_basic_deterministic()
for (name, value) in six.iteritems(video_hparams.values()):
if name in hparams_keys:
hparams.set_hparam(name, value)
else:
hparams.add_hparam(name, value)
# Mostly to avoid decaying WM params when training the policy.
hparams.weight_decay = 0
return hparams |
Atari parameters with world model as policy. | def ppo_tiny_world_model():
"""Atari parameters with world model as policy."""
hparams = ppo_original_params()
hparams.policy_network = "next_frame_basic_deterministic"
hparams_keys = hparams.values().keys()
video_hparams = basic_deterministic_params.next_frame_tiny()
for (name, value) in six.iteritems(video_hparams.values()):
if name in hparams_keys:
hparams.set_hparam(name, value)
else:
hparams.add_hparam(name, value)
hparams.weight_decay = 0
return hparams |
Atari parameters with stochastic discrete world model as policy. | def ppo_original_world_model_stochastic_discrete():
"""Atari parameters with stochastic discrete world model as policy."""
hparams = ppo_original_params()
hparams.policy_network = "next_frame_basic_stochastic_discrete"
hparams_keys = hparams.values().keys()
video_hparams = basic_stochastic.next_frame_basic_stochastic_discrete()
for (name, value) in six.iteritems(video_hparams.values()):
if name in hparams_keys:
hparams.set_hparam(name, value)
else:
hparams.add_hparam(name, value)
# To avoid OOM. Probably way to small.
hparams.optimization_batch_size = 1
hparams.weight_decay = 0
return hparams |
Returns a function creating a simulated env, in or out of graph.
Args:
**env_kwargs: kwargs to pass to the simulated env constructor.
Returns:
Function in_graph -> env. | def make_simulated_env_fn(**env_kwargs):
"""Returns a function creating a simulated env, in or out of graph.
Args:
**env_kwargs: kwargs to pass to the simulated env constructor.
Returns:
Function in_graph -> env.
"""
def env_fn(in_graph):
class_ = SimulatedBatchEnv if in_graph else SimulatedBatchGymEnv
return class_(**env_kwargs)
return env_fn |
Extracts simulated env kwargs from real_env and loop hparams. | def make_simulated_env_kwargs(real_env, hparams, **extra_kwargs):
"""Extracts simulated env kwargs from real_env and loop hparams."""
objs_and_attrs = [
(real_env, [
"reward_range", "observation_space", "action_space", "frame_height",
"frame_width"
]),
(hparams, ["frame_stack_size", "intrinsic_reward_scale"])
]
kwargs = {
attr: getattr(obj, attr) # pylint: disable=g-complex-comprehension
for (obj, attrs) in objs_and_attrs for attr in attrs
}
kwargs["model_name"] = hparams.generative_model
kwargs["model_hparams"] = trainer_lib.create_hparams(
hparams.generative_model_params
)
if hparams.wm_policy_param_sharing:
kwargs["model_hparams"].optimizer_zero_grads = True
kwargs.update(extra_kwargs)
return kwargs |
Get a policy network.
Args:
observations: observations
hparams: parameters
action_space: action space
Returns:
Tuple (action logits, value). | def get_policy(observations, hparams, action_space):
"""Get a policy network.
Args:
observations: observations
hparams: parameters
action_space: action space
Returns:
Tuple (action logits, value).
"""
if not isinstance(action_space, gym.spaces.Discrete):
raise ValueError("Expecting discrete action space.")
obs_shape = common_layers.shape_list(observations)
(frame_height, frame_width) = obs_shape[2:4]
# TODO(afrozm): We have these dummy problems mainly for hparams, so cleanup
# when possible and do this properly.
if hparams.policy_problem_name == "dummy_policy_problem_ttt":
tf.logging.info("Using DummyPolicyProblemTTT for the policy.")
policy_problem = tic_tac_toe_env.DummyPolicyProblemTTT()
else:
tf.logging.info("Using DummyPolicyProblem for the policy.")
policy_problem = DummyPolicyProblem(action_space, frame_height, frame_width)
trainer_lib.add_problem_hparams(hparams, policy_problem)
hparams.force_full_predict = True
model = registry.model(hparams.policy_network)(
hparams, tf.estimator.ModeKeys.TRAIN
)
try:
num_target_frames = hparams.video_num_target_frames
except AttributeError:
num_target_frames = 1
features = {
"inputs": observations,
"input_action": tf.zeros(obs_shape[:2] + [1], dtype=tf.int32),
"input_reward": tf.zeros(obs_shape[:2] + [1], dtype=tf.int32),
"targets": tf.zeros(obs_shape[:1] + [num_target_frames] + obs_shape[2:]),
"target_action": tf.zeros(
obs_shape[:1] + [num_target_frames, 1], dtype=tf.int32),
"target_reward": tf.zeros(
obs_shape[:1] + [num_target_frames, 1], dtype=tf.int32),
"target_policy": tf.zeros(
obs_shape[:1] + [num_target_frames] + [action_space.n]),
"target_value": tf.zeros(
obs_shape[:1] + [num_target_frames])
}
with tf.variable_scope(tf.get_variable_scope(), reuse=tf.AUTO_REUSE):
t2t_model.create_dummy_vars()
(targets, _) = model(features)
return (targets["target_policy"][:, 0, :], targets["target_value"][:, 0]) |
Base set of hparams for model-free PPO. | def rlmf_tictactoe():
"""Base set of hparams for model-free PPO."""
hparams = rlmf_original()
hparams.game = "tictactoe"
hparams.rl_env_name = "T2TEnv-TicTacToeEnv-v0"
# Since we don't have any no-op actions, otherwise we have to have an
# attribute called `get_action_meanings`.
hparams.eval_max_num_noops = 0
hparams.max_num_noops = 0
hparams.rl_should_derive_observation_space = False
hparams.policy_network = "feed_forward_categorical_policy"
hparams.base_algo_params = "ppo_ttt_params"
# Number of last observations to feed to the agent
hparams.frame_stack_size = 1
return hparams |
Tiny set of hparams for model-free PPO. | def rlmf_tiny():
"""Tiny set of hparams for model-free PPO."""
hparams = rlmf_original()
hparams = hparams.override_from_dict(rlmf_tiny_overrides())
hparams.batch_size = 2
hparams.base_algo_params = "ppo_original_tiny"
hparams.add_hparam("ppo_epochs_num", 3)
hparams.add_hparam("ppo_epoch_length", 2)
return hparams |
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