def fn():
"""Loss function for when number of input and output boxes is positive."""
if is_balanced:
weights = loss_utils.get_balanced_loss_weights_multiclass(
labels=input_boxes_instance_id)
else:
weights = tf.ones([tf.shape(input_boxes_instance_id)[0], 1],
dtype=tf.float32)
gt_center = tf.reshape(input_boxes_center, [-1, 3])
predicted_center = tf.reshape(output_boxes_center, [-1, 3])
if loss_type == 'huber':
loss_fn = tf.keras.losses.Huber(
delta=delta, reduction=tf.keras.losses.Reduction.NONE)
elif loss_type == 'absolute_difference':
loss_fn = tf.keras.losses.MeanAbsoluteError(
reduction=tf.keras.losses.Reduction.NONE)
else:
raise ValueError(('Unknown loss type %s.' % loss_type))
center_losses = loss_fn(y_true=gt_center, y_pred=predicted_center)
return tf.reduce_mean(center_losses * tf.reshape(weights, [-1]))
def eq_cifar_fn(x, output_dim=10, trainable=True):
gconv_indices, gconv_shape_info, w_shape = gconv2d_util(h_input='Z2',
h_output='C4',
in_channels=3,
out_channels=8,
ksize=3)
w = tf.get_variable('w1', shape=w_shape)
conv1 = gconv2d(input=x,
filter=w,
strides=[1, 2, 2, 1],
padding='SAME',
gconv_indices=gconv_indices,
gconv_shape_info=gconv_shape_info)
tf.add_to_collection('conv_output1', conv1)
pool1 = tf.layers.max_pooling2d(inputs=conv1, pool_size=[2, 2], strides=2)
gconv_indices, gconv_shape_info, w_shape = gconv2d_util(h_input='C4',
h_output='C4',
in_channels=16,
out_channels=32,
ksize=5)
w = tf.get_variable('w2', shape=w_shape)
conv2 = gconv2d(input=conv1,
filter=w,
strides=[1, 2, 2, 1],
padding='SAME',
gconv_indices=gconv_indices,
gconv_shape_info=gconv_shape_info)
pool2 = tf.layers.max_pooling2d(inputs=conv2, pool_size=[2, 2], strides=2)
gconv_indices, gconv_shape_info, w_shape = gconv2d_util(h_input='C4',
h_output='C4',
in_channels=8,
out_channels=2,
ksize=5)
w = tf.get_variable('w3', shape=w_shape)
conv3 = gconv2d(input=conv2,
filter=w,
strides=[1, 1, 1, 1],
padding='SAME',
gconv_indices=gconv_indices,
gconv_shape_info=gconv_shape_info)
conv3 = tf.reshape(conv3,
conv3.get_shape().as_list()[:3] + [4] + [out_channels])
conv3 = tf.reduce_mean(conv3, axis=3)
pool3 = tf.layers.max_pooling2d(inputs=conv3, pool_size=[2, 2], strides=2)
pool3_flat = tf.layers.flatten(pool3)
u = pool3_flat
u = tf.layers.dense(inputs=pool3_flat,
units=output_dim,
activation=tf.nn.relu,
trainable=trainable)
tf.add_to_collection('conv_output2', conv2)
return u
def generate_plan(self, time_step: ActionTimeStep, state):
assert self._reward_func is not None, ("specify reward function "
"before planning")
assert self._dynamics_func is not None, ("specify dynamics function "
"before planning")
self._plan_optimizer.set_cost(self._calc_cost_for_action_sequence)
opt_action = self._plan_optimizer.obtain_solution(time_step, state)
action = opt_action[:, 0]
action = tf.reshape(action, [time_step.observation.shape[0], -1])
return action
def _build_network(self,
residual_layer_size=1024,
num_residual_layers=2,
dropout_amount=0.5,
small_context_loss_weight=0.0,
max_num_distractors=-1):
"""Builds an MLP with residual connections.
Args:
residual_layer_size: Dimension for linear layer to add to MLP.
num_residual_layers: Number of residual layer.
dropout_amount: If training, how much dropout to use in each layer.
small_context_loss_weight: If >0, in addition to the loss with many
distractors, add another loss where the only distractors are the
sentences of the context.
max_num_distractors: The maximum number of distractors provided at each
train step.
Returns:
The input and output tensors for the network, with the input being a
placeholder variable.
"""
self.small_context_loss_weight = small_context_loss_weight
self._max_num_distractors = max_num_distractors
# x starts off with dimension [batch_size x num_sentences x emb_size].
# Convert it to [batch_size x (num_sentences*emb_size)].
x_input = tf.keras.Input(
shape=[self._num_input_sentences, self._embedding_dim])
flattened_shape = [-1, self._num_input_sentences * self._embedding_dim]
x = tf.reshape(x_input, flattened_shape)
def block(start_x, embedding_size):
x = tf.keras.layers.Dense(embedding_size,
activation='relu')(start_x)
x = tf.keras.layers.Dropout(dropout_amount)(x)
x = tf.keras.layers.Dense(embedding_size, activation='relu')(x)
return x + start_x
x = tf.keras.layers.LayerNormalization(axis=1)(x)
# First bring dimension down to desired.
x = tf.keras.layers.Dense(residual_layer_size)(x)
# Add specified number of residual layers.
for _ in range(num_residual_layers):
x = block(x, residual_layer_size)
# Go back up to desired dimension.
x = tf.keras.layers.Dense(self._embedding_dim, activation='linear')(x)
x = tf.keras.layers.LayerNormalization(axis=1)(x)
return x_input, x
def call(self, inputs, outer_rank):
if inputs.dtype != self._sample_spec.dtype:
raise ValueError(
'Inputs to NormalProjectionNetwork must match the sample_spec.dtype.'
)
# outer_rank is needed because the projection is not done on the raw
# observations so getting the outer rank is hard as there is no spec to
# compare to.
batch_squash = network_utils.BatchSquash(outer_rank)
inputs = batch_squash.flatten(inputs)
means = self._means_projection_layer(inputs)
means = tf.reshape(means, [-1] + self._sample_spec.shape.as_list())
if self._state_dependent_std:
stds = self._stddev_projection_layer(inputs)
else:
stds = self._bias(tf.zeros_like(means))
stds = tf.reshape(stds, [-1] + self._sample_spec.shape.as_list())
inv_stds = self._std_transform(stds)
if self._max_std is not None:
inv_stds += 1 / (self._max_std - self._min_std)
stds = 1. / inv_stds
if self._min_std > 0:
stds += self._min_std
stds = tf.cast(stds, self._sample_spec.dtype)
means = means * stds
# If not scaling the distribution later, use a normalized mean.
if not self._scale_distribution and self._mean_transform is not None:
means = self._mean_transform(means, self._sample_spec)
means = tf.cast(means, self._sample_spec.dtype)
means = batch_squash.unflatten(means)
stds = batch_squash.unflatten(stds)
return self.output_spec.build_distribution(loc=means, scale=stds)
def _attend(self, query, key, value, key_class_id):
"""Transformer attention function."""
with tf.name_scope('attend'):
q_shape = tf.shape(query)
v_shape = tf.shape(value)
n_q = q_shape[0]
h_q = q_shape[1]
w_q = q_shape[2]
d = q_shape[3]
n_v = v_shape[0]
h_v = v_shape[1]
w_v = v_shape[2]
c = v_shape[3]
q = tf.reshape(query, [-1, d]) # [n_q*Hq*Wq, d]
k = tf.reshape(key, [-1, d])
# [n_v*Hv*Wv, d] x [Nq*Hq*Wq, d] --> [n_v*Hv*Wv, Nq*Hq*Wq]
logits = tf.matmul(k, q, transpose_b=True)
d_scale = tf.rsqrt(tf.cast(d, logits.dtype))
# logits: [n_v, Hv*Wv, n_q*Hq*Wq]
logits = tf.reshape(d_scale * logits, [n_v, h_v * w_v, -1])
# attn: [n_v, Hv*Wv, n_q*Hq*Wq]
attn = self.get_support_set_softmax(logits, key_class_id)
# aggregate:
v = tf.reshape(value, [n_v, h_v * w_v, c])
# [n_v, Hv*Wv, n_q*Hq*Wq] x [n_v, Hv*Wv, c] --> [n_v, n_q*Hq*Wq, c]
v_agg = tf.einsum('ijk,ijl->ikl', attn, v)
v_agg = tf.reshape(v_agg, [n_v, n_q, h_q, w_q, c])
v_agg.set_shape([None, None, None, None, value.shape[-1]])
return v_agg # [N_c, n_q, Hq, Wq, c]
def compute_episode_stats(episode):
"""Computes various episode stats: way, shots, and class IDs.
Args:
episode: An EpisodeDataset.
Returns:
way: An int constant tensor. The number of classes in the episode.
shots: An int 1D tensor: The number of support examples per class.
class_ids: An int 1D tensor: (absolute) class IDs.
"""
# The train labels of the next episode.
train_labels = episode.train_labels
# Compute way.
episode_classes, _ = tf.unique(train_labels)
way = tf.size(episode_classes)
# Compute shots.
class_ids = tf.reshape(tf.range(way), [way, 1])
class_labels = tf.reshape(train_labels, [1, -1])
is_equal = tf.equal(class_labels, class_ids)
shots = tf.reduce_sum(tf.cast(is_equal, tf.int32), axis=1)
# Compute class_ids.
class_ids, _ = tf.unique(episode.train_class_ids)
return way, shots, class_ids
def _expand_to_population(self, data):
"""Expand the input tensor to a population of replications
Args:
data (tf.Tensor): input data with shape [batch_size, ...]
Returns:
data_population (tf.Tensor) with shape
[batch_size * self._population_size, ...].
For example data tensor [[a, b], [c, d]] and a population_size of 2,
we have the following data_population tensor as output
[[a, b], [a, b], [c, d], [c, d]]
"""
data_population = tf.tile(tf.expand_dims(
data, 1), [1, self._population_size] + [1] * len(data.shape[1:]))
data_population = tf.reshape(data_population,
[-1] + data.shape[1:].as_list())
return data_population
def compute_kitti_difficulty(boxes, occlusions, truncations, image_height):
"""Computes box difficulty as Hard(1), Moderate(2), Easy(3) or 0 (Super hard).
Easy: height >=40 Px, occlusion <= 0, truncation <= 0.15
Moderate: height >=25 Px, occlusion <= 1, truncation <= 0.30
Hard: height >=25 Px, occlusion <= 2, truncation <= 0.50
Note that 'Hard' box is also 'Moderate' and 'Easy'.
Returns a (N, 1) tensor containing object difficulty with following labelmap:
0: SuperHard
1: Hard
2: Moderate
3: Easy
TODO(abhijitkundu): Since difficulty level is very specific to kitti, this
function should be in kitti evaluation rather than detection preprocessor.
Args:
boxes: (N, 4) tensor of 2d boxes with [ymin, xmin, ymax, xmax] each row.
occlusions: (N, 1) tensor containing box occlusion level
truncations: (N, 1) tensor containing box truncation level
image_height: Image height.
Returns:
A (N, 1) int32 tensor containing per box difficulty labels with 0 (SuperHard),
1 (Hard), 2 (Moderate) and 3 (Easy).
"""
# box heights in pixels
heights = tf.reshape(
(boxes[:, 2] - boxes[:, 0]), [-1, 1]) * tf.cast(image_height,
dtype=tf.float32)
# compute binary masks for each difficulty level
is_easy = (heights >= 40.0) & (occlusions <= 0) & (truncations <= 0.15)
is_moderate = (heights >= 25.0) & (occlusions <= 1) & (truncations <= 0.30)
is_hard = (heights >= 25.0) & (occlusions <= 2) & (truncations <= 0.50)
# set difficulty map
difficulty = tf.maximum(
tf.maximum(
tf.cast(is_hard, dtype=tf.int32) * ObjectDifficulty.HARD,
tf.cast(is_moderate, dtype=tf.int32) * ObjectDifficulty.MODERATE),
tf.cast(is_easy, dtype=tf.int32) * ObjectDifficulty.EASY)
return difficulty
def random_flip_left_right(images, flow, mask, probability):
"""Performs a random left/right flip."""
perform_flip = tf.less(tf.random.uniform([]), probability)
# apply flip
images = tf.cond(pred=perform_flip,
true_fn=lambda: tf.reverse(images, axis=[-2]),
false_fn=lambda: images)
if flow is not None:
flow = tf.cond(pred=perform_flip,
true_fn=lambda: tf.reverse(flow, axis=[-2]),
false_fn=lambda: flow)
mask = tf.cond(pred=perform_flip,
true_fn=lambda: tf.reverse(mask, axis=[-2]),
false_fn=lambda: mask)
# correct sign of flow
sign_correction = tf.reshape([1.0, -1.0], [1, 1, 2])
flow = tf.cond(pred=perform_flip,
true_fn=lambda: flow * sign_correction,
false_fn=lambda: flow)
return images, flow, mask
def random_flip_up_down(images, flow=None, mask=None):
"""Performs a random up/down flip."""
# 50/50 chance
perform_flip = tf.equal(tf.random.uniform([], maxval=2, dtype=tf.int32), 1)
# apply flip
images = tf.cond(pred=perform_flip,
true_fn=lambda: tf.reverse(images, axis=[-3]),
false_fn=lambda: images)
if flow is not None:
flow = tf.cond(pred=perform_flip,
true_fn=lambda: tf.reverse(flow, axis=[-3]),
false_fn=lambda: flow)
mask = tf.cond(pred=perform_flip,
true_fn=lambda: tf.reverse(mask, axis=[-3]),
false_fn=lambda: mask)
# correct sign of flow
sign_correction = tf.reshape([-1.0, 1.0], [1, 1, 2])
flow = tf.cond(pred=perform_flip,
true_fn=lambda: flow * sign_correction,
false_fn=lambda: flow)
return images, flow, mask
def _rotate(img, mask=None):
if angle_radian == 0.0:
# early return if no resizing is required
if mask is not None:
return img, mask
else:
return img
if mask is not None:
# multiply with mask, to ensure non-valid locations are zero
img = tf.math.multiply(img, mask)
# rotate img
img_rotated = tfa_image.rotate(img,
angle_radian,
interpolation='BILINEAR')
# rotate mask (will serve as normalization weights)
mask_rotated = tfa_image.rotate(mask,
angle_radian,
interpolation='BILINEAR')
# normalize sparse flow field and mask
img_rotated = tf.math.multiply(
img_rotated, tf.math.reciprocal_no_nan(mask_rotated))
mask_rotated = tf.math.multiply(
mask_rotated, tf.math.reciprocal_no_nan(mask_rotated))
else:
img_rotated = tfa_image.rotate(img,
angle_radian,
interpolation='BILINEAR')
if is_flow:
# If image is a flow image, scale flow values to be consistent with the
# rotation.
cos = tf.math.cos(angle_radian)
sin = tf.math.sin(angle_radian)
rotation_matrix = tf.reshape([cos, sin, -sin, cos], [2, 2])
img_rotated = tf.linalg.matmul(img_rotated, rotation_matrix)
if mask is not None:
return img_rotated, mask_rotated
return img_rotated
def compute_prototypes(embeddings, onehot_labels):
"""Compute class prototypes over the last dimension of embeddings.
Args:
embeddings: Tensor of examples of shape [num_examples] + embedding_shape
onehot_labels: Tensor of one-hot encoded labels of shape [num_examples,
num_classes].
Returns:
prototypes: Tensor of class prototypes of shape [num_classes,
embedding_size].
"""
# Sums each class' embeddings. [num classes] + embedding shape.
embedding_indices = 'klm'[:len(embeddings.shape) - 1]
class_sums = tf.einsum('ij,i{0}->j{0}'.format(embedding_indices),
onehot_labels, embeddings)
# The prototype of each class is the averaged embedding of its examples.
class_num_images = tf.reduce_sum(input_tensor=onehot_labels, axis=0) # [way].
prototypes = tf.math.divide_no_nan(
class_sums,
tf.reshape(class_num_images, [-1] + [1] * (len(embeddings.shape) - 1)))
return prototypes
