def ComputeMoments(inputs,
padding,
reduce_over_dims,
cumulative_axis=None,
enable_cross_replica_sum_on_tpu=False,
keepdims=False):
"""Computes mean and variance over the valid data points in inputs."""
mask = 1.0 - padding
inputs = py_utils.with_dependencies([
py_utils.assert_equal(tf.rank(inputs), tf.rank(mask)),
py_utils.assert_greater_equal(mask, tf.zeros_like(mask)),
], inputs)
sum_v = tf.reduce_sum(inputs * tf.cast(mask, inputs.dtype),
reduce_over_dims,
keepdims=keepdims)
count_v = tf.reduce_sum(mask, reduce_over_dims, keepdims=keepdims)
if cumulative_axis is not None:
sum_v = tf.math.cumsum(sum_v, axis=cumulative_axis)
count_v = tf.math.cumsum(count_v, axis=cumulative_axis)
# Input shape is guaranteed to be a multiple of mask shape because the
# inputs * mask op above was successfully broadcasted.
input_size_on_reduced_dims = tf.reduce_prod(
tf.gather(tf.shape(inputs), reduce_over_dims))
mask_size_on_reduced_dims = tf.reduce_prod(
tf.gather(tf.shape(mask), reduce_over_dims))
mask_multiplier = tf.math.truediv(input_size_on_reduced_dims,
mask_size_on_reduced_dims)
count_v *= tf.cast(mask_multiplier, count_v.dtype)
if py_utils.use_tpu() and enable_cross_replica_sum_on_tpu:
sum_v = tf.tpu.cross_replica_sum(sum_v)
count_v = tf.tpu.cross_replica_sum(count_v)
count_v = tf.maximum(count_v, 1.0)
mean = sum_v / count_v
sum_vv = tf.reduce_sum((inputs - mean) * (inputs - mean) * mask,
reduce_over_dims,
keepdims=keepdims)
if cumulative_axis is not None:
sum_vv = tf.math.cumsum(sum_vv, axis=cumulative_axis)
if py_utils.use_tpu() and enable_cross_replica_sum_on_tpu:
sum_vv = tf.tpu.cross_replica_sum(sum_vv)
variance = py_utils.with_dependencies([
py_utils.assert_greater_equal(sum_vv, tf.zeros_like(sum_vv)),
], sum_vv / count_v)
return mean, variance
def _Moments(inputs, mask, enable_cross_replica_sum_on_tpu=False):
"""Computes mean and variance over the valid data points in inputs."""
inputs = py_utils.with_dependencies([
py_utils.assert_equal(tf.rank(inputs), tf.rank(mask)),
py_utils.assert_greater_equal(mask, tf.zeros_like(mask)),
], inputs)
rank = tf.rank(mask)
reduce_over_dims = tf.range(0, rank - 1)
sum_v = tf.reduce_sum(inputs * tf.cast(mask, inputs.dtype),
reduce_over_dims)
count_v = tf.reduce_sum(mask, reduce_over_dims)
# Input shape is guaranteed to be a multiple of mask shape because the
# inputs * mask op above was successfully broadcasted.
mask_multiplier = tf.shape(inputs)[:-1] // tf.shape(mask)[:-1]
count_v *= tf.cast(tf.reduce_prod(mask_multiplier), count_v.dtype)
if py_utils.use_tpu() and enable_cross_replica_sum_on_tpu:
sum_v = tf.tpu.cross_replica_sum(sum_v)
count_v = tf.tpu.cross_replica_sum(count_v)
count_v = tf.maximum(count_v, 1.0)
mean = sum_v / count_v
sum_vv = tf.reduce_sum((inputs - mean) * (inputs - mean) * mask,
reduce_over_dims)
if py_utils.use_tpu() and enable_cross_replica_sum_on_tpu:
sum_vv = tf.tpu.cross_replica_sum(sum_vv)
variance = py_utils.with_dependencies([
py_utils.assert_greater_equal(sum_vv, tf.zeros_like(sum_vv)),
], sum_vv / count_v)
return mean, variance
def FProp(self, theta, inputs):
"""Apply projection to inputs.
Args:
theta: A NestedMap object containing weights' values of this layer and its
children layers.
inputs: The inputs tensor. Shaped [..., input_dims].
Returns:
Projected inputs.
"""
p = self.params
with tf.name_scope(p.name):
computation_cost.Add(
self, 'flops',
tf.reduce_prod(tf.to_int64(tf.shape(inputs)[:-1])) * tf.to_int64(
symbolic.EvalExpr(symbolic.TENSOR_VALUES,
p.input_dims * p.output_dims)) * 2)
use_tpu = py_utils.use_tpu()
if use_tpu and inputs.shape is not None and inputs.shape.rank < 26:
# Avoids reshape if feasible and uses Einsum.
if inputs.shape.rank == 2:
return tf.matmul(inputs, theta.w)
else:
s = ''.join([chr(x) for x in range(97, 123)]) # abc...xyz
r = inputs.shape.rank
return tf.einsum('{0}y,yz->{0}z'.format(s[:r - 1]), inputs, theta.w)
input_dim = py_utils.GetShape(inputs)[-1]
act = tf.matmul(tf.reshape(inputs, [-1, input_dim]), theta.w)
output_dim = tf.shape(theta.w)[-1]
act = tf.reshape(act,
tf.concat([tf.shape(inputs)[:-1], [output_dim]], axis=0))
return act
def _InputBatch(self):
length = tf.reduce_prod(self.shape)
counter = summary_utils.StatsCounter('CountingInputGenerator')
new_value = tf.cast(counter.IncBy(length), dtype=tf.int32) - length
new_value = tf.stop_gradient(new_value)
values = new_value + tf.range(length)
shaped_values = tf.reshape(tf.cast(values, dtype=tf.float32), self.shape)
targets = tf.reduce_sum(shaped_values, axis=0)
return py_utils.NestedMap(src_ids=shaped_values, tgt_ids=targets)
def FProp(self, theta, inputs):
"""Apply projection to inputs.
Args:
theta: A NestedMap object containing weights' values of this layer and its
children layers.
inputs: The inputs tensor. Shaped [..., input_dims].
Returns:
Projected inputs.
"""
p = self.params
with tf.name_scope(p.name):
computation_cost.Add(
self, 'flops',
tf.reduce_prod(tf.cast(tf.shape(inputs)[:-1], tf.int64)) *
tf.cast(symbolic.ToTensor(p.input_dims * p.output_dims), tf.int64) *
2)
return py_utils.ProjectLastDim(inputs, theta.w, p.input_dims,
p.output_dims)
