def _apply_roll_biz_space(self, date_tensor, biz_days, is_bizday,
roll_convention):
"""Applies roll in business day space."""
if roll_convention == constants.BusinessDayConvention.NONE:
# If no business convention is specified, return the current business
# day.
return biz_days
if roll_convention == constants.BusinessDayConvention.FOLLOWING:
return tf.where(is_bizday, biz_days, biz_days + 1)
if roll_convention == constants.BusinessDayConvention.PRECEDING:
return biz_days
if roll_convention == constants.BusinessDayConvention.MODIFIED_FOLLOWING:
maybe_prev_biz_day = biz_days
maybe_next_biz_day = tf.where(is_bizday, biz_days, biz_days + 1)
maybe_next_biz_ordinal = self._from_biz_space(maybe_next_biz_day)
take_previous = tf.not_equal(_get_month(maybe_next_biz_ordinal),
date_tensor.month())
return tf.where(take_previous, maybe_prev_biz_day,
maybe_next_biz_day)
if roll_convention == constants.BusinessDayConvention.MODIFIED_PRECEDING:
maybe_prev_biz_day = biz_days
maybe_next_biz_day = tf.where(is_bizday, biz_days, biz_days + 1)
maybe_prev_biz_ordinal = self._from_biz_space(maybe_prev_biz_day)
take_next = tf.not_equal(_get_month(maybe_prev_biz_ordinal),
date_tensor.month())
return tf.where(take_next, maybe_next_biz_day, maybe_prev_biz_day)
raise ValueError(
'Unsupported roll convention: {}'.format(roll_convention))
def jointly_tied_pairs_body(first, t, i):
not_equal = tf.math.logical_or(
tf.not_equal(y_true[lexa[first]], y_true[lexa[i]]),
tf.not_equal(y_pred[lexa[first]], y_pred[lexa[i]]))
return (tf.where(not_equal, i, first),
tf.where(not_equal, t + ((i - first) * (i - first - 1)) // 2,
t), i + 1)
def test_sparse_weights_nonzero_prob_of_one_works(self):
true_weights = tf.constant([0., 0., 2., 0., -2.])
model, observed_time_series, _ = self._build_test_model(
num_timesteps=20,
num_features=5,
missing_prob=0.,
true_noise_scale=0.1,
weights=true_weights,
weights_prior_scale=None, # Default g-prior.
sparse_weights_nonzero_prob=1.)
@tf.function(autograph=False)
def do_sampling():
return gibbs_sampler.fit_with_gibbs_sampling(
model,
observed_time_series,
num_results=100,
num_warmup_steps=100,
seed=test_util.test_seed(sampler_type='stateless'))
samples = self.evaluate(do_sampling())
mean_weights = tf.reduce_mean(samples.weights, axis=-2)
nonzero_probs = tf.reduce_mean(
tf.cast(tf.not_equal(samples.weights, 0.), tf.float32),
axis=-2)
# Increasing `num_timesteps` relative to `num_features` would give more
# precise weight estimates, at the cost of longer test runtime.
# TODO(axch, cgs): Can we use assertAllMeansClose here too? The
# samples are presumably not IID across axis=0, so the
# statistical assumptions are not satisfied.
self.assertAllClose(mean_weights, true_weights, atol=0.3)
self.assertAllClose(nonzero_probs, [1., 1., 1., 1., 1.])
def scale_channel(im, c):
"""Scale the data in the channel to implement equalize."""
im = tf.cast(im[:, :, c], tf.int32)
# Compute the histogram of the image channel.
histo = tf.histogram_fixed_width(im, [0, 255], nbins=256)
# For the purposes of computing the step, filter out the nonzeros.
nonzero = tf.where(tf.not_equal(histo, 0))
nonzero_histo = tf.reshape(tf.gather(histo, nonzero), [-1])
step = (tf.reduce_sum(nonzero_histo) - nonzero_histo[-1]) // 255
def build_lut(histo, step):
# Compute the cumulative sum, shifting by step // 2
# and then normalization by step.
lut = (tf.cumsum(histo) + (step // 2)) // step
# Shift lut, prepending with 0.
lut = tf.concat([[0], lut[:-1]], 0)
# Clip the counts to be in range. This is done
# in the C code for image.point.
return tf.clip_by_value(lut, 0, 255)
# If step is zero, return the original image. Otherwise, build
# lut from the full histogram and step and then index from it.
result = tf.cond(tf.equal(step, 0), lambda: im,
lambda: tf.gather(build_lut(histo, step), im))
return tf.cast(result, tf.uint8)
def test_sparse_regression_recovers_plausible_weights(self):
true_weights = tf.constant([0., 0., 2., 0., -2.])
model, observed_time_series, _ = self._build_test_model(
num_timesteps=20,
num_features=5,
missing_prob=0.,
true_noise_scale=0.1,
weights=true_weights,
weights_prior_scale=None, # Default g-prior.
sparse_weights_nonzero_prob=0.4)
@tf.function(autograph=False)
def do_sampling():
return gibbs_sampler.fit_with_gibbs_sampling(
model,
observed_time_series,
num_results=100,
num_warmup_steps=100,
seed=test_util.test_seed(sampler_type='stateless'))
samples = self.evaluate(do_sampling())
mean_weights = tf.reduce_mean(samples.weights, axis=-2)
nonzero_probs = tf.reduce_mean(tf.cast(
tf.not_equal(samples.weights, 0.), tf.float32),
axis=-2)
# Increasing `num_timesteps` relative to `num_features` would give more
# precise weight estimates, at the cost of longer test runtime.
self.assertAllClose(mean_weights, true_weights, atol=0.3)
self.assertAllClose(nonzero_probs, [0., 0., 1., 0., 1.], atol=0.2)
def call(self, inputs):
boolean_mask = tf.reduce_any(tf.not_equal(inputs, self.mask_value),
axis=-1,
keepdims=True)
outputs = inputs * tf.cast(boolean_mask, inputs.dtype)
# Compute the mask and outputs simultaneously.
outputs._keras_mask = tf.squeeze(boolean_mask, axis=-1)
return outputs
def _calculate_spline_coeffs_clamped_or_first_derivative(
dx,
dd,
superdiag,
subdiag,
diag_values,
rhs,
dtype,
boundary_condition_type,
left_boundary_value=None,
right_boundary_value=None):
"""Calculates the coefficients for the spline interpolation if the boundary condition type is CLAMPED/FIXED_FIRST_DERIVATIVE."""
zero = tf.zeros_like(dx[..., :1], dtype=dtype)
one = tf.ones_like(dx[..., :1], dtype=dtype)
diag_values = tf.concat([2.0 * dx[..., :1], diag_values, zero], axis=-1)
superdiag = tf.concat([dx[..., :1], superdiag, zero], axis=-1)
subdiag = tf.concat([zero, subdiag, dx[..., -1:]], axis=-1)
# locate right boundary when duplicates exists
dx = tf.concat((one, dx, zero), axis=-1)
dx_right = dx[..., 1:]
dx_left = dx[..., :-1]
right_boundary = tf.math.logical_and(tf.equal(dx_right, 0),
tf.not_equal(dx_left, 0))
# For diag_values, at the right boundary, fill the value as 2.0 * dx.
# For the right padding beyond boundary, fill the default value as 1.0.
# No need to operate on super_diag/sub_diag,
# since dx[..., -1:] is already zero
diag_values = tf.where(right_boundary, 2.0 * dx_left, diag_values)
diag_values = tf.where(tf.equal(dx_left, 0), one, diag_values)
# build diagonals
diagonals = tf.stack([superdiag, diag_values, subdiag], axis=-2)
# build rhs
left_boundary_tensor = tf.zeros_like(dx[..., :1], dtype=dtype)
right_boundary_tensor = tf.zeros_like(dx[..., :1], dtype=dtype)
if boundary_condition_type == BoundaryConditionType.FIXED_FIRST_DERIVATIVE:
left_boundary_tensor = tf.convert_to_tensor(left_boundary_value,
dtype=dtype,
name="left_boundary_value")
right_boundary_tensor = tf.convert_to_tensor(
right_boundary_value, dtype=dtype, name="right_boundary_value")
top_rhs = 3.0 * (dd[..., :1] - left_boundary_tensor[..., :1])
rhs = tf.concat([top_rhs, rhs, zero], axis=-1)
# For rhs, at the right boundary, fill the value as bottom_rhs.
# For the right padding beyond boundary, fill the default value as 0.0.
dd_left = tf.concat((one, dd), axis=-1)
bottom_rhs = -3.0 * (dd_left - right_boundary_tensor[..., :1])
rhs = tf.where(right_boundary, bottom_rhs, rhs)
rhs = tf.where(tf.equal(dd_left, 0), zero, rhs)
spline_coeffs = tf.linalg.tridiagonal_solve(diagonals,
rhs,
partial_pivoting=False)
return spline_coeffs
def box_loss(self, box_outputs, box_targets, num_positives): """Computes RetinaNet box regression loss.""" # The delta is typically around the mean value of regression target. # for instances, the regression targets of 512x512 input with 6 anchors on # P3-P7 pyramid is about [0.1, 0.1, 0.2, 0.2]. normalizer = num_positives * 4.0 mask = tf.not_equal(box_targets, 0.0) box_loss = self._huber_loss(box_targets, box_outputs, sample_weight=mask) box_loss /= normalizer return box_loss
def copy_lc_weights_2_to_3(lc_layer_2_from, lc_layer_3_to):
lc_2_kernel, lc_2_bias = lc_layer_2_from.weights
lc_2_kernel_masked = lc_2_kernel * lc_layer_2_from.kernel_mask
lc_2_kernel_masked = keras.layers.local.make_2d(
lc_2_kernel_masked, split_dim=keras.backend.ndim(lc_2_kernel_masked) // 2)
lc_2_kernel_masked = keras.backend.transpose(lc_2_kernel_masked)
lc_2_kernel_mask = tf.not_equal(lc_2_kernel_masked, 0)
lc_2_kernel_flat = tf.compat.v1.boolean_mask(
lc_2_kernel_masked, lc_2_kernel_mask)
lc_2_kernel_flat = keras.backend.get_value(lc_2_kernel_flat)
lc_2_bias = keras.backend.get_value(lc_2_bias)
lc_layer_3_to.set_weights([lc_2_kernel_flat, lc_2_bias])
def body_fn(i, partial, outputs):
"""Body function for while_loop.
Args:
i: integer scalar
partial: dictionary of Tensor (partially-constructed example)
outputs: dictionary of TensorArray
Returns:
A triple containing the new values of the inputs.
"""
can_append = True
one_example = {}
for k in keys:
val = tf.cast(x[k][i], tf.int32)
val = val[:tf.
reduce_sum(tf.cast(tf.not_equal(val, 0), tf.int32))]
one_example[k] = val
for k in keys:
can_append = tf.logical_and(
can_append,
tf.less_equal(
tf.size(partial[k]) + tf.size(one_example[k]),
length[k]))
def false_fn():
return write_packed_example(partial, outputs)
def true_fn():
return partial, outputs
partial, outputs = tf.cond(can_append, true_fn, false_fn)
new_partial = {}
for k in keys:
new_seq = one_example[k][:length[k]]
new_seq_len = tf.size(new_seq)
new_partial[k] = tf.concat([partial[k], new_seq], 0)
if _annotate_key(k):
new_partial[k + '_position'] = tf.concat([
partial[k + '_position'],
tf.range(new_seq_len, dtype=tf.int32)
], 0)
partial = new_partial
return i + 1, partial, outputs
def body(left, right, lexicographic):
# We make a single pass through the list using right and left, where right
# advances and left chases it looking for spans that are equal in their
# primary key to then institute a sort on the secondary key.
not_equal = tf.not_equal(primary_ordered[left], primary_ordered[right])
def secondary_sort():
x = tf.concat([
lexicographic[0:left],
tf.gather(permutation[left:right],
tf.argsort(tf.gather(secondary,
permutation[left:right]))),
lexicographic[right:n],
],
axis=0)
tensorshape_util.set_shape(x, [n])
return x
return (tf.where(not_equal, right, left), right + 1,
tf.cond(not_equal, secondary_sort, lambda: lexicographic))
def padded_cross_entropy_loss(logits, labels, smoothing, vocab_size):
"""Calculate cross entropy loss while ignoring padding.
Args:
logits: Tensor of size [batch_size, length_logits, vocab_size]
labels: Tensor of size [batch_size, length_labels]
smoothing: Label smoothing constant, used to determine the on and off values
vocab_size: int size of the vocabulary
Returns:
Returns the cross entropy loss and weight tensors: float32 tensors with
shape [batch_size, max(length_logits, length_labels)]
"""
with tf.name_scope("loss"):
if labels is not None:
# Calculate smoothing cross entropy
with tf.name_scope("smoothing_cross_entropy"):
confidence = 1.0 - smoothing
vocab_float = tf.cast(vocab_size - 1, tf.float32)
low_confidence = (1.0 - confidence) / vocab_float
soft_targets = tf.one_hot(
labels,
depth=vocab_size,
on_value=confidence,
off_value=low_confidence)
xentropy = tf.nn.softmax_cross_entropy_with_logits(
logits=logits, labels=soft_targets)
# Calculate the best (lowest) possible value of cross entropy, and
# subtract from the cross entropy loss.
normalizing_constant = -(
confidence * tf.math.log(confidence) + vocab_float *
low_confidence * tf.math.log(low_confidence + 1e-20))
xentropy -= normalizing_constant
weights = tf.cast(tf.not_equal(labels, 0), tf.float32)
loss = tf.reduce_sum(xentropy) / tf.reduce_sum(weights)
else:
loss = tf.constant(0.0)
return loss
def _rpn_box_loss(self,
box_outputs,
box_targets,
normalizer=1.0,
delta=1. / 9):
"""Computes box regression loss."""
# The delta is typically around the mean value of regression target.
# for instances, the regression targets of 512x512 input with 6 anchors on
# P2-P6 pyramid is about [0.1, 0.1, 0.2, 0.2].
with tf.compat.v1.name_scope('rpn_box_loss'):
mask = tf.not_equal(box_targets, 0.0)
# The loss is normalized by the sum of non-zero weights before additional
# normalizer provided by the function caller.
box_loss = tf.compat.v1.losses.huber_loss(
box_targets,
box_outputs,
weights=mask,
delta=delta,
reduction=tf.compat.v1.losses.Reduction.SUM_BY_NONZERO_WEIGHTS)
box_loss /= normalizer
return box_loss
def copy_lc_weights_2_to_1(lc_layer_2_from, lc_layer_1_to):
lc_2_kernel, lc_2_bias = lc_layer_2_from.weights
lc_2_kernel_masked = lc_2_kernel * lc_layer_2_from.kernel_mask
data_format = lc_layer_2_from.data_format
if data_format == 'channels_first':
if isinstance(lc_layer_2_from, keras.layers.LocallyConnected1D):
permutation = (3, 0, 1, 2)
elif isinstance(lc_layer_2_from, keras.layers.LocallyConnected2D):
permutation = (4, 5, 0, 1, 2, 3)
else:
raise NotImplementedError(lc_layer_2_from)
elif data_format == 'channels_last':
if isinstance(lc_layer_2_from, keras.layers.LocallyConnected1D):
permutation = (2, 0, 1, 3)
elif isinstance(lc_layer_2_from, keras.layers.LocallyConnected2D):
permutation = (3, 4, 0, 1, 2, 5)
else:
raise NotImplementedError(lc_layer_2_from)
else:
raise NotImplementedError(data_format)
lc_2_kernel_masked = keras.backend.permute_dimensions(
lc_2_kernel_masked, permutation)
lc_2_kernel_mask = tf.not_equal(
lc_2_kernel_masked, 0)
lc_2_kernel_flat = tf.compat.v1.boolean_mask(
lc_2_kernel_masked, lc_2_kernel_mask)
lc_2_kernel_reshaped = keras.backend.reshape(lc_2_kernel_flat,
lc_layer_1_to.kernel.shape)
lc_2_kernel_reshaped = keras.backend.get_value(lc_2_kernel_reshaped)
lc_2_bias = keras.backend.get_value(lc_2_bias)
lc_layer_1_to.set_weights([lc_2_kernel_reshaped, lc_2_bias])
