def _transform(self, x, compute_y, compute_log_det):
w, b, u, u_hat = self._w, self._b, self._u, self._u_hat
# flatten x for better performance
x_flatten, s1, s2 = flatten_to_ndims(x, 2) # x.shape == [?, n_units]
wxb = tf.matmul(x_flatten, w, transpose_b=True) + b # shape == [?, 1]
tanh_wxb = tf.tanh(wxb) # shape == [?, 1]
# compute y = f(x)
y = None
if compute_y:
y = x_flatten + u_hat * tanh_wxb # shape == [?, n_units]
y = unflatten_from_ndims(y, s1, s2)
# compute log(det|df/dz|)
log_det = None
if compute_log_det:
grad = 1. - tf.square(tanh_wxb) # dtanh(x)/dx = 1 - tanh^2(x)
phi = grad * w # shape == [?, n_units]
u_phi = tf.matmul(phi, u_hat, transpose_b=True) # shape == [?, 1]
det_jac = 1. + u_phi # shape == [?, 1]
log_det = tf.log(tf.abs(det_jac)) # shape == [?, 1]
log_det = unflatten_from_ndims(tf.squeeze(log_det, -1), s1, s2)
# now returns the transformed sample and log-determinant
return y, log_det
def _pool2d(pool_fn,
input,
pool_size,
strides=(1, 1),
channels_last=True,
padding='same',
name=None,
default_name=None):
input, _, data_format = validate_conv2d_input(input, channels_last)
# check functional arguments
padding = validate_enum_arg('padding',
str(padding).upper(), ['VALID', 'SAME'])
strides = validate_conv2d_strides_tuple('strides', strides, channels_last)
ksize = validate_conv2d_strides_tuple('pool_size', pool_size,
channels_last)
# call pooling
with tf.name_scope(name, default_name=default_name):
output, s1, s2 = flatten_to_ndims(input, 4)
output = pool_fn(value=output,
ksize=ksize,
strides=strides,
padding=padding,
data_format=data_format)
output = unflatten_from_ndims(output, s1, s2)
return output
def conv2d_ans(input,
padding,
kernel,
bias,
strides,
dilations,
activation_fn=None,
normalizer_fn=None):
"""Produce the expected answer of conv2d."""
strides = (strides, ) * 2 if is_integer(strides) else tuple(strides)
strides = (1, ) + strides + (1, )
session = tf.get_default_session()
input, s1, s2 = flatten_to_ndims(input, 4)
padding = padding.upper()
if dilations > 1:
assert (not any(i > 1 for i in strides))
output = tf.nn.atrous_conv2d(value=input,
filters=kernel,
rate=dilations,
padding=padding)
else:
output = tf.nn.conv2d(input=input,
filter=kernel,
strides=strides,
padding=padding,
data_format='NHWC',
dilations=[1] * 4)
if bias is not None:
output += bias
if normalizer_fn:
output = normalizer_fn(output)
if activation_fn:
output = activation_fn(output)
output = unflatten_from_ndims(output, s1, s2)
output = session.run(output)
return output
def pool2d_ans(pool_fn, input, pool_size, padding, strides):
"""Produce the expected answer of ?_pool2d."""
strides = (strides, ) * 2 if is_integer(strides) else tuple(strides)
strides = (1, ) + strides + (1, )
ksize = (pool_size, ) * 2 if is_integer(pool_size) else tuple(
pool_size)
ksize = (1, ) + ksize + (1, )
session = tf.get_default_session()
input, s1, s2 = flatten_to_ndims(input, 4)
padding = padding.upper()
output = pool_fn(
value=input,
ksize=ksize,
strides=strides,
padding=padding,
data_format='NHWC',
)
output = unflatten_from_ndims(output, s1, s2)
output = session.run(output)
return output
def space_to_depth(input, block_size, channels_last=True, name=None):
"""
Wraps :func:`tf.space_to_depth`, to support tensors higher than 4-d.
Args:
input: The input tensor, at least 4-d.
block_size (int): An int >= 2, the size of the spatial block.
channels_last (bool): Whether or not the channels axis
is the last axis in the input tensor?
Returns:
tf.Tensor: The output tensor.
See Also:
:func:`tf.space_to_depth`
"""
block_size = int(block_size)
data_format = 'NHWC' if channels_last else 'NCHW'
input = tf.convert_to_tensor(input)
with tf.name_scope(name or 'space_to_depth', values=[input]):
output, s1, s2 = flatten_to_ndims(input, ndims=4)
output = tf.space_to_depth(output, block_size, data_format=data_format)
output = unflatten_from_ndims(output, s1, s2)
return output
def conv2d(input,
out_channels,
kernel_size,
strides=(1, 1),
dilations=1,
padding='same',
channels_last=True,
activation_fn=None,
normalizer_fn=None,
weight_norm=False,
kernel=None,
kernel_initializer=None,
kernel_regularizer=None,
kernel_constraint=None,
use_bias=None,
bias=None,
bias_initializer=tf.zeros_initializer(),
bias_regularizer=None,
bias_constraint=None,
trainable=True,
name=None,
scope=None):
"""
2D convolutional layer.
Args:
input (Tensor): The input tensor, at least 4-d.
out_channels (int): The channel numbers of the output.
kernel_size (int or (int, int)): Kernel size over spatial dimensions.
strides (int or (int, int)): Strides over spatial dimensions.
dilations (int): The dilation factor over spatial dimensions.
padding: One of {"valid", "same"}, case in-sensitive.
channels_last (bool): Whether or not the channel axis is the last
axis in `input`? (i.e., the data format is "NHWC")
activation_fn: The activation function.
normalizer_fn: The normalizer function.
weight_norm (bool or (tf.Tensor) -> tf.Tensor)):
If :obj:`True`, apply :func:`~tfsnippet.layers.weight_norm` on
`kernel`. `use_scale` will be :obj:`True` if `normalizer_fn`
is not specified, and :obj:`False` otherwise. The axis reduction
will be determined by the layer.
If it is a callable function, then it will be used to normalize
the `kernel` instead of :func:`~tfsnippet.layers.weight_norm`.
The user must ensure the axis reduction is correct by themselves.
kernel (Tensor): Instead of creating a new variable, use this tensor.
kernel_initializer: The initializer for `kernel`.
Would be ``default_kernel_initializer(...)`` if not specified.
kernel_regularizer: The regularizer for `kernel`.
kernel_constraint: The constraint for `kernel`.
use_bias (bool or None): Whether or not to use `bias`?
If :obj:`True`, will always use bias.
If :obj:`None`, will use bias only if `normalizer_fn` is not given.
If :obj:`False`, will never use bias.
Default is :obj:`None`.
bias (Tensor): Instead of creating a new variable, use this tensor.
bias_initializer: The initializer for `bias`.
bias_regularizer: The regularizer for `bias`.
bias_constraint: The constraint for `bias`.
trainable (bool): Whether or not the parameters are trainable?
Returns:
tf.Tensor: The output tensor.
"""
input, in_channels, data_format = \
validate_conv2d_input(input, channels_last)
out_channels = validate_positive_int_arg('out_channels', out_channels)
dtype = input.dtype.base_dtype
# check functional arguments
padding = validate_enum_arg('padding',
str(padding).upper(), ['VALID', 'SAME'])
strides = validate_conv2d_strides_tuple('strides', strides, channels_last)
dilations = validate_positive_int_arg('dilations', dilations)
if dilations > 1 and not channels_last:
raise ValueError('`channels_last` == False is incompatible with '
'`dilations` > 1.')
if any(i > 1 for i in strides) and dilations > 1:
raise ValueError('`strides` > 1 is incompatible with `dilations` > 1.')
weight_norm_fn = validate_weight_norm_arg(weight_norm,
axis=-1,
use_scale=normalizer_fn is None)
if use_bias is None:
use_bias = normalizer_fn is None
# get the specification of outputs and parameters
kernel_size = validate_conv2d_size_tuple('kernel_size', kernel_size)
kernel_shape = kernel_size + (in_channels, out_channels)
bias_shape = (out_channels, )
# validate the parameters
if kernel is not None:
kernel_spec = ParamSpec(shape=kernel_shape, dtype=dtype)
kernel = kernel_spec.validate('kernel', kernel)
if kernel_initializer is None:
kernel_initializer = default_kernel_initializer(weight_norm)
if bias is not None:
bias_spec = ParamSpec(shape=bias_shape, dtype=dtype)
bias = bias_spec.validate('bias', bias)
# the main part of the conv2d layer
with tf.variable_scope(scope, default_name=name or 'conv2d'):
# create the variables
if kernel is None:
kernel = model_variable('kernel',
shape=kernel_shape,
dtype=dtype,
initializer=kernel_initializer,
regularizer=kernel_regularizer,
constraint=kernel_constraint,
trainable=trainable)
if weight_norm_fn is not None:
kernel = weight_norm_fn(kernel)
if use_bias and bias is None:
bias = model_variable('bias',
shape=bias_shape,
initializer=bias_initializer,
regularizer=bias_regularizer,
constraint=bias_constraint,
trainable=trainable)
# flatten to 4d
output, s1, s2 = flatten_to_ndims(input, 4)
# do convolution
if dilations > 1:
output = tf.nn.atrous_conv2d(value=output,
filters=kernel,
rate=dilations,
padding=padding)
else:
output = tf.nn.conv2d(input=output,
filter=kernel,
strides=strides,
padding=padding,
data_format=data_format,
dilations=[1] * 4)
# add bias
if use_bias:
output = tf.nn.bias_add(output, bias, data_format=data_format)
# apply the normalization function if specified
if normalizer_fn is not None:
output = normalizer_fn(output)
# apply the activation function if specified
if activation_fn is not None:
output = activation_fn(output)
# unflatten back to original shape
output = unflatten_from_ndims(output, s1, s2)
return output
def deconv2d(input,
out_channels,
kernel_size,
strides=(1, 1),
padding='same',
channels_last=True,
output_shape=None,
activation_fn=None,
normalizer_fn=None,
weight_norm=False,
kernel=None,
kernel_initializer=None,
kernel_regularizer=None,
kernel_constraint=None,
use_bias=None,
bias=None,
bias_initializer=tf.zeros_initializer(),
bias_regularizer=None,
bias_constraint=None,
trainable=True,
name=None,
scope=None):
"""
2D deconvolutional layer.
Args:
input (Tensor): The input tensor, at least 4-d.
out_channels (int): The channel numbers of the deconvolution output.
kernel_size (int or (int, int)): Kernel size over spatial dimensions.
strides (int or (int, int)): Strides over spatial dimensions.
padding: One of {"valid", "same"}, case in-sensitive.
channels_last (bool): Whether or not the channel axis is the last
axis in `input`? (i.e., the data format is "NHWC")
output_shape: If specified, use this as the shape of the
deconvolution output; otherwise compute the size of each dimension
by::
output_size = input_size * strides
if padding == 'valid':
output_size += max(kernel_size - strides, 0)
activation_fn: The activation function.
normalizer_fn: The normalizer function.
weight_norm (bool or (tf.Tensor) -> tf.Tensor)):
If :obj:`True`, apply :func:`~tfsnippet.layers.weight_norm` on
`kernel`. `use_scale` will be :obj:`True` if `normalizer_fn`
is not specified, and :obj:`False` otherwise. The axis reduction
will be determined by the layer.
If it is a callable function, then it will be used to normalize
the `kernel` instead of :func:`~tfsnippet.layers.weight_norm`.
The user must ensure the axis reduction is correct by themselves.
kernel (Tensor): Instead of creating a new variable, use this tensor.
kernel_initializer: The initializer for `kernel`.
Would be ``default_kernel_initializer(...)`` if not specified.
kernel_regularizer: The regularizer for `kernel`.
kernel_constraint: The constraint for `kernel`.
use_bias (bool or None): Whether or not to use `bias`?
If :obj:`True`, will always use bias.
If :obj:`None`, will use bias only if `normalizer_fn` is not given.
If :obj:`False`, will never use bias.
Default is :obj:`None`.
bias (Tensor): Instead of creating a new variable, use this tensor.
bias_initializer: The initializer for `bias`.
bias_regularizer: The regularizer for `bias`.
bias_constraint: The constraint for `bias`.
trainable (bool): Whether or not the parameters are trainable?
Returns:
tf.Tensor: The output tensor.
"""
input, in_channels, data_format = \
validate_conv2d_input(input, channels_last)
out_channels = validate_positive_int_arg('out_channels', out_channels)
dtype = input.dtype.base_dtype
# check functional arguments
padding = validate_enum_arg('padding',
str(padding).upper(), ['VALID', 'SAME'])
strides = validate_conv2d_strides_tuple('strides', strides, channels_last)
weight_norm_fn = validate_weight_norm_arg(weight_norm,
axis=-1,
use_scale=normalizer_fn is None)
if use_bias is None:
use_bias = normalizer_fn is None
# get the specification of outputs and parameters
kernel_size = validate_conv2d_size_tuple('kernel_size', kernel_size)
kernel_shape = kernel_size + (out_channels, in_channels)
bias_shape = (out_channels, )
given_h, given_w = None, None
given_output_shape = output_shape
if is_tensor_object(given_output_shape):
given_output_shape = tf.convert_to_tensor(given_output_shape)
elif given_output_shape is not None:
given_h, given_w = given_output_shape
# validate the parameters
if kernel is not None:
kernel_spec = ParamSpec(shape=kernel_shape, dtype=dtype)
kernel = kernel_spec.validate('kernel', kernel)
if kernel_initializer is None:
kernel_initializer = default_kernel_initializer(weight_norm)
if bias is not None:
bias_spec = ParamSpec(shape=bias_shape, dtype=dtype)
bias = bias_spec.validate('bias', bias)
# the main part of the conv2d layer
with tf.variable_scope(scope, default_name=name or 'deconv2d'):
with tf.name_scope('output_shape'):
# detect the input shape and axis arrangements
input_shape = get_static_shape(input)
if channels_last:
c_axis, h_axis, w_axis = -1, -3, -2
else:
c_axis, h_axis, w_axis = -3, -2, -1
output_shape = [None, None, None, None]
output_shape[c_axis] = out_channels
if given_output_shape is None:
if input_shape[h_axis] is not None:
output_shape[h_axis] = get_deconv_output_length(
input_shape[h_axis], kernel_shape[0], strides[h_axis],
padding)
if input_shape[w_axis] is not None:
output_shape[w_axis] = get_deconv_output_length(
input_shape[w_axis], kernel_shape[1], strides[w_axis],
padding)
else:
if not is_tensor_object(given_output_shape):
output_shape[h_axis] = given_h
output_shape[w_axis] = given_w
# infer the batch shape in 4-d
batch_shape = input_shape[:-3]
if None not in batch_shape:
output_shape[0] = int(np.prod(batch_shape))
# now the static output shape is ready
output_static_shape = tf.TensorShape(output_shape)
# prepare for the dynamic batch shape
if output_shape[0] is None:
output_shape[0] = tf.reduce_prod(get_shape(input)[:-3])
# prepare for the dynamic spatial dimensions
if output_shape[h_axis] is None or output_shape[w_axis] is None:
if given_output_shape is None:
input_shape = get_shape(input)
if output_shape[h_axis] is None:
output_shape[h_axis] = get_deconv_output_length(
input_shape[h_axis], kernel_shape[0],
strides[h_axis], padding)
if output_shape[w_axis] is None:
output_shape[w_axis] = get_deconv_output_length(
input_shape[w_axis], kernel_shape[1],
strides[w_axis], padding)
else:
assert (is_tensor_object(given_output_shape))
with assert_deps([
assert_rank(given_output_shape, 1),
assert_scalar_equal(tf.size(given_output_shape), 2)
]):
output_shape[h_axis] = given_output_shape[0]
output_shape[w_axis] = given_output_shape[1]
# compose the final dynamic shape
if any(is_tensor_object(s) for s in output_shape):
output_shape = tf.stack(output_shape)
else:
output_shape = tuple(output_shape)
# create the variables
if kernel is None:
kernel = model_variable('kernel',
shape=kernel_shape,
dtype=dtype,
initializer=kernel_initializer,
regularizer=kernel_regularizer,
constraint=kernel_constraint,
trainable=trainable)
if weight_norm_fn is not None:
kernel = weight_norm_fn(kernel)
if use_bias and bias is None:
bias = model_variable('bias',
shape=bias_shape,
initializer=bias_initializer,
regularizer=bias_regularizer,
constraint=bias_constraint,
trainable=trainable)
# flatten to 4d
output, s1, s2 = flatten_to_ndims(input, 4)
# do convolution or deconvolution
output = tf.nn.conv2d_transpose(value=output,
filter=kernel,
output_shape=output_shape,
strides=strides,
padding=padding,
data_format=data_format)
if output_static_shape is not None:
output.set_shape(output_static_shape)
# add bias
if use_bias:
output = tf.nn.bias_add(output, bias, data_format=data_format)
# apply the normalization function if specified
if normalizer_fn is not None:
output = normalizer_fn(output)
# apply the activation function if specified
if activation_fn is not None:
output = activation_fn(output)
# unflatten back to original shape
output = unflatten_from_ndims(output, s1, s2)
return output