def testAddWeight(self):
layer = base_layers.Layer(name='my_layer')
# Test basic variable creation.
variable = layer.add_variable(
'my_var', [2, 2], initializer=init_ops.zeros_initializer())
self.assertEqual(variable.name, 'my_layer/my_var:0')
self.assertListEqual(layer.variables, [variable])
self.assertListEqual(layer.trainable_variables, [variable])
self.assertListEqual(layer.non_trainable_variables, [])
self.assertListEqual(layer.variables,
ops.get_collection(ops.GraphKeys.TRAINABLE_VARIABLES))
# Test non-trainable variable creation.
# layer.add_variable should work even outside `build` and `call`.
variable_2 = layer.add_variable(
'non_trainable_var', [2, 2],
initializer=init_ops.zeros_initializer(),
trainable=False)
self.assertListEqual(layer.variables, [variable, variable_2])
self.assertListEqual(layer.trainable_variables, [variable])
self.assertListEqual(layer.non_trainable_variables, [variable_2])
self.assertEqual(
len(ops.get_collection(ops.GraphKeys.TRAINABLE_VARIABLES)), 1)
if context.in_graph_mode():
# regularizers only supported in GRAPH mode.
regularizer = lambda x: math_ops.reduce_sum(x) * 1e-3
variable = layer.add_variable(
'reg_var', [2, 2],
initializer=init_ops.zeros_initializer(),
regularizer=regularizer)
self.assertEqual(len(layer.losses), 1)
def weighted_moving_average(value,
decay,
weight,
truediv=True,
collections=None,
name=None):
"""Compute the weighted moving average of `value`.
Conceptually, the weighted moving average is:
`moving_average(value * weight) / moving_average(weight)`,
where a moving average updates by the rule
`new_value = decay * old_value + (1 - decay) * update`
Internally, this Op keeps moving average variables of both `value * weight`
and `weight`.
Args:
value: A numeric `Tensor`.
decay: A float `Tensor` or float value. The moving average decay.
weight: `Tensor` that keeps the current value of a weight.
Shape should be able to multiply `value`.
truediv: Boolean, if `True`, dividing by `moving_average(weight)` is
floating point division. If `False`, use division implied by dtypes.
collections: List of graph collections keys to add the internal variables
`value * weight` and `weight` to.
Defaults to `[GraphKeys.GLOBAL_VARIABLES]`.
name: Optional name of the returned operation.
Defaults to "WeightedMovingAvg".
Returns:
An Operation that updates and returns the weighted moving average.
"""
# Unlike assign_moving_average, the weighted moving average doesn't modify
# user-visible variables. It is the ratio of two internal variables, which are
# moving averages of the updates. Thus, the signature of this function is
# quite different than assign_moving_average.
if collections is None:
collections = [ops.GraphKeys.GLOBAL_VARIABLES]
with variable_scope.variable_scope(name, "WeightedMovingAvg",
[value, weight, decay]) as scope:
value_x_weight_var = variable_scope.get_variable(
"value_x_weight",
initializer=init_ops.zeros_initializer(value.get_shape(),
dtype=value.dtype),
trainable=False,
collections=collections)
weight_var = variable_scope.get_variable(
"weight",
initializer=init_ops.zeros_initializer(weight.get_shape(),
dtype=weight.dtype),
trainable=False,
collections=collections)
numerator = assign_moving_average(
value_x_weight_var, value * weight, decay, zero_debias=False)
denominator = assign_moving_average(
weight_var, weight, decay, zero_debias=False)
if truediv:
return math_ops.truediv(numerator, denominator, name=scope.name)
else:
return math_ops.div(numerator, denominator, name=scope.name)
def __init__(self,
axis=-1,
momentum=0.99,
epsilon=1e-3,
center=True,
scale=True,
beta_initializer=init_ops.zeros_initializer(),
gamma_initializer=init_ops.ones_initializer(),
moving_mean_initializer=init_ops.zeros_initializer(),
moving_variance_initializer=init_ops.ones_initializer(),
beta_regularizer=None,
gamma_regularizer=None,
trainable=True,
name=None,
**kwargs):
super(BatchNormalization, self).__init__(
name=name, trainable=trainable, **kwargs)
self.axis = axis
self.momentum = momentum
self.epsilon = epsilon
self.center = center
self.scale = scale
self.beta_initializer = beta_initializer
self.gamma_initializer = gamma_initializer
self.moving_mean_initializer = moving_mean_initializer
self.moving_variance_initializer = moving_variance_initializer
self.beta_regularizer = beta_regularizer
self.gamma_regularizer = gamma_regularizer
def testKernelStateList(self):
"""Test that transition kernel works with list input to `state`."""
num_chains = 2
loc_one = variable_scope.get_variable(
"loc_one", [num_chains],
initializer=init_ops.zeros_initializer())
loc_two = variable_scope.get_variable(
"loc_two", [num_chains], initializer=init_ops.zeros_initializer())
def target_log_prob_fn(loc_one, loc_two):
loc = array_ops.stack([loc_one, loc_two])
log_prob = mvn_tril_lib.MultivariateNormalTriL(
loc=constant_op.constant([0., 0.]),
scale_tril=constant_op.constant([[0.1, 0.1], [0.0, 0.1]])).log_prob(
loc)
return math_ops.reduce_sum(log_prob, 0)
def proposal_fn(loc_one, loc_two):
loc_one_proposal = mh.proposal_normal(scale=0.05)
loc_two_proposal = mh.proposal_normal(scale=0.05)
loc_one_sample, _ = loc_one_proposal(loc_one)
loc_two_sample, _ = loc_two_proposal(loc_two)
return [loc_one_sample, loc_two_sample], None
new_state, _ = mh.kernel(
target_log_prob_fn=target_log_prob_fn,
proposal_fn=proposal_fn,
current_state=[loc_one, loc_two],
seed=12415)
loc_one_update = loc_one.assign(new_state[0])
loc_two_update = loc_two.assign(new_state[1])
init = variables.initialize_all_variables()
with self.test_session() as sess:
sess.run(init)
loc_one_samples = []
loc_two_samples = []
for _ in range(10000):
loc_one_sample, loc_two_sample = sess.run(
[loc_one_update, loc_two_update])
loc_one_samples.append(loc_one_sample)
loc_two_samples.append(loc_two_sample)
loc_one_samples = np.array(loc_one_samples)
loc_two_samples = np.array(loc_two_samples)
loc_one_samples = loc_one_samples[1000:] # drop samples for burn-in
loc_two_samples = loc_two_samples[1000:] # drop samples for burn-in
self.assertAllClose(np.mean(loc_one_samples, 0),
np.array([0.] * num_chains),
rtol=1e-5, atol=1e-1)
self.assertAllClose(np.mean(loc_two_samples, 0),
np.array([0.] * num_chains),
rtol=1e-5, atol=1e-1)
self.assertAllClose(np.std(loc_one_samples, 0),
np.array([0.1] * num_chains),
rtol=1e-5, atol=1e-1)
self.assertAllClose(np.std(loc_two_samples, 0),
np.array([0.1] * num_chains),
rtol=1e-5, atol=1e-1)
def _auc_hist_accumulate(hist_true, hist_false, nbins, collections):
"""Accumulate histograms in new variables."""
with variable_scope.variable_scope(
None, 'hist_accumulate', [hist_true, hist_false]):
# Holds running total histogram of scores for records labeled True.
hist_true_acc = variable_scope.get_variable(
'hist_true_acc',
initializer=init_ops.zeros_initializer(
[nbins],
dtype=hist_true.dtype),
collections=collections,
trainable=False)
# Holds running total histogram of scores for records labeled False.
hist_false_acc = variable_scope.get_variable(
'hist_false_acc',
initializer=init_ops.zeros_initializer(
[nbins],
dtype=hist_false.dtype),
collections=collections,
trainable=False)
update_op = control_flow_ops.group(
hist_true_acc.assign_add(hist_true),
hist_false_acc.assign_add(hist_false),
name='update_op')
return hist_true_acc, hist_false_acc, update_op
def linear_module(x, output_size):
w = variable_scope.get_variable(
"w", shape=[x.get_shape()[1], output_size],
initializer=init_ops.zeros_initializer())
b = variable_scope.get_variable(
"b", shape=[output_size],
initializer=init_ops.zeros_initializer())
return (math_ops.matmul(x, w) + b), w
def _templated():
v = variable_scope.get_variable(
"v", shape=[1], initializer=init_ops.zeros_initializer(),
use_resource=True)
v2 = variable_scope.get_variable(
"v2", shape=[1], initializer=init_ops.zeros_initializer(),
use_resource=True)
return v, v + 1., v2
def __init__(self,
axis=-1,
momentum=0.99,
epsilon=1e-3,
center=True,
scale=True,
beta_initializer=init_ops.zeros_initializer(),
gamma_initializer=init_ops.ones_initializer(),
moving_mean_initializer=init_ops.zeros_initializer(),
moving_variance_initializer=init_ops.ones_initializer(),
beta_regularizer=None,
gamma_regularizer=None,
beta_constraint=None,
gamma_constraint=None,
renorm=False,
renorm_clipping=None,
renorm_momentum=0.99,
fused=None,
trainable=True,
virtual_batch_size=None,
adjustment=None,
name=None,
**kwargs):
super(BatchNormalization, self).__init__(
name=name, trainable=trainable, **kwargs)
if isinstance(axis, list):
self.axis = axis[:]
else:
self.axis = axis
self.momentum = momentum
self.epsilon = epsilon
self.center = center
self.scale = scale
self.beta_initializer = beta_initializer
self.gamma_initializer = gamma_initializer
self.moving_mean_initializer = moving_mean_initializer
self.moving_variance_initializer = moving_variance_initializer
self.beta_regularizer = beta_regularizer
self.gamma_regularizer = gamma_regularizer
self.beta_constraint = beta_constraint
self.gamma_constraint = gamma_constraint
self.renorm = renorm
self.virtual_batch_size = virtual_batch_size
self.adjustment = adjustment
if fused is None:
fused = True
self.fused = fused
self._bessels_correction_test_only = True
if renorm:
renorm_clipping = renorm_clipping or {}
keys = ['rmax', 'rmin', 'dmax']
if set(renorm_clipping) - set(keys):
raise ValueError('renorm_clipping %s contains keys not in %s' %
(renorm_clipping, keys))
self.renorm_clipping = renorm_clipping
self.renorm_momentum = renorm_momentum
def testAddWeight(self):
layer = base_layers.Layer(name='my_layer')
# Test basic variable creation.
variable = layer.add_variable(
'my_var', [2, 2], initializer=init_ops.zeros_initializer())
self.assertEqual(variable.name, 'my_layer/my_var:0')
self.assertEqual(layer.variables, [variable])
self.assertEqual(layer.trainable_variables, [variable])
self.assertEqual(layer.non_trainable_variables, [])
if not context.executing_eagerly():
self.assertEqual(
layer.variables,
ops.get_collection(ops.GraphKeys.TRAINABLE_VARIABLES))
# Test non-trainable variable creation.
# layer.add_variable should work even outside `build` and `call`.
variable_2 = layer.add_variable(
'non_trainable_var', [2, 2],
initializer=init_ops.zeros_initializer(),
trainable=False)
self.assertEqual(layer.variables, [variable, variable_2])
self.assertEqual(layer.trainable_variables, [variable])
self.assertEqual(layer.non_trainable_variables, [variable_2])
if not context.executing_eagerly():
self.assertEqual(
len(ops.get_collection(ops.GraphKeys.TRAINABLE_VARIABLES)), 1)
regularizer = lambda x: math_ops.reduce_sum(x) * 1e-3
_ = layer.add_variable(
'reg_var', [2, 2],
initializer=init_ops.zeros_initializer(),
regularizer=regularizer)
self.assertEqual(len(layer.losses), 1)
added_variable = [False]
# Test that sync `ON_READ` variables are defaulted to be non-trainable.
variable_3 = layer.add_variable(
'sync_on_read_var', [2, 2],
initializer=init_ops.zeros_initializer(),
synchronization=variable_scope.VariableSynchronization.ON_READ,
aggregation=variable_scope.VariableAggregation.SUM)
self.assertEqual(layer.non_trainable_variables, [variable_2, variable_3])
@def_function.function
def function_adds_weight():
if not added_variable[0]:
layer.add_variable(
'reg_var_from_function', [2, 2],
initializer=init_ops.zeros_initializer(),
regularizer=regularizer)
added_variable[0] = True
function_adds_weight()
self.assertEqual(len(layer.losses), 2)
def testLSTMLayer(self):
# Run with all-0 weights, no padding.
o = self._RunLSTMLayer('zeros', init_ops.zeros_initializer(), 0., 0., 0.)
self.assertAllClose(o, [[[0.]] * self._batch_size] * 3)
o = self._RunLSTMLayer('zeros', init_ops.zeros_initializer(), 0., 1., 0.)
self.assertAllClose(o, [[[.25]] * self._batch_size,
[[.125]] * self._batch_size,
[[.0625]] * self._batch_size])
o = self._RunLSTMLayer('zeros', init_ops.zeros_initializer(), 1., 0., 0.)
self.assertAllClose(o, [[[0.]] * self._batch_size] * 3)
o = self._RunLSTMLayer('zeros', init_ops.zeros_initializer(), 1., 1., 0.)
self.assertAllClose(o, [[[.25]] * self._batch_size,
[[.125]] * self._batch_size,
[[.0625]] * self._batch_size])
# Run with all-1 weights, no padding.
weight1 = 1.
for m_init in [0., 1.]:
for c_init in [0., 1.]:
o = self._RunLSTMLayer('ones',
init_ops.ones_initializer(), m_init, c_init, 0.)
m0 = self._NextM(self._inputs, weight1, m_init, c_init)
c0 = self._NextC(self._inputs, weight1, m_init, c_init)
self.assertAllClose(o[0], m0)
m1 = self._NextM(self._inputs, weight1, m0, c0)
c1 = self._NextC(self._inputs, weight1, m0, c0)
self.assertAllClose(o[1], m1)
m2 = self._NextM(self._inputs, weight1, m1, c1)
self.assertAllClose(o[2], m2)
# Run with random weights.
for weight in np.random.rand(3):
weight_tf = constant_op.constant(weight, dtypes.float32)
random_weight = lambda shape, w=weight_tf: array_ops.fill(shape, w)
# No padding.
for m_init in [0., 1.]:
for c_init in [0., 1.]:
o = self._RunLSTMLayer('random', random_weight, m_init, c_init, 0.)
m0 = self._NextM(self._inputs, weight, m_init, c_init)
c0 = self._NextC(self._inputs, weight, m_init, c_init)
self.assertAllClose(o[0], m0)
m1 = self._NextM(self._inputs, weight, m0, c0)
c1 = self._NextC(self._inputs, weight, m0, c0)
self.assertAllClose(o[1], m1)
m2 = self._NextM(self._inputs, weight, m1, c1)
self.assertAllClose(o[2], m2)
# Set padding.
o = self._RunLSTMLayer('random', random_weight, 0., 0., 1.)
self.assertAllClose(o, [[[0.]] * self._batch_size] * 3)
o = self._RunLSTMLayer('random', random_weight, 0., 1., 1.)
self.assertAllClose(o, [[[0.]] * self._batch_size] * 3)
o = self._RunLSTMLayer('random', random_weight, 1., 0., 1.)
self.assertAllClose(o, [[[1.]] * self._batch_size] * 3)
o = self._RunLSTMLayer('random', random_weight, 1., 1., 1.)
self.assertAllClose(o, [[[1.]] * self._batch_size] * 3)
def __init__(self,
axis=-1,
momentum=0.99,
epsilon=1e-3,
center=True,
scale=True,
beta_initializer=init_ops.zeros_initializer(),
gamma_initializer=init_ops.ones_initializer(),
moving_mean_initializer=init_ops.zeros_initializer(),
moving_variance_initializer=init_ops.ones_initializer(),
beta_regularizer=None,
gamma_regularizer=None,
beta_constraint=None,
gamma_constraint=None,
renorm=False,
renorm_clipping=None,
renorm_momentum=0.99,
fused=None,
trainable=True,
name=None,
**kwargs):
super(BatchNormalization, self).__init__(
name=name, trainable=trainable, **kwargs)
self.axis = axis
self.momentum = momentum
self.epsilon = epsilon
self.center = center
self.scale = scale
self.beta_initializer = beta_initializer
self.gamma_initializer = gamma_initializer
self.moving_mean_initializer = moving_mean_initializer
self.moving_variance_initializer = moving_variance_initializer
self.beta_regularizer = beta_regularizer
self.gamma_regularizer = gamma_regularizer
self.beta_constraint = beta_constraint
self.gamma_constraint = gamma_constraint
self.renorm = renorm
# This environment variable is only used during the testing period of fused
# batch norm and will be removed after that.
if fused is None:
fused = _FUSED_DEFAULT
self.fused = fused
self._bessels_correction_test_only = True
if renorm:
renorm_clipping = renorm_clipping or {}
keys = ['rmax', 'rmin', 'dmax']
if set(renorm_clipping) - set(keys):
raise ValueError('renorm_clipping %s contains keys not in %s' %
(renorm_clipping, keys))
self.renorm_clipping = renorm_clipping
self.renorm_momentum = renorm_momentum
def __init__(self,
axis=-1,
momentum=0.99,
epsilon=1e-3,
center=True,
scale=True,
beta_initializer=init_ops.zeros_initializer(),
gamma_initializer=init_ops.ones_initializer(),
moving_mean_initializer=init_ops.zeros_initializer(),
moving_variance_initializer=init_ops.ones_initializer(),
beta_regularizer=None,
gamma_regularizer=None,
renorm=False,
renorm_clipping=None,
renorm_momentum=0.99,
fused=False,
trainable=True,
name=None,
**kwargs):
super(BatchNormalization, self).__init__(
name=name, trainable=trainable, **kwargs)
self.axis = axis
self.momentum = momentum
self.epsilon = epsilon
self.center = center
self.scale = scale
self.beta_initializer = beta_initializer
self.gamma_initializer = gamma_initializer
self.moving_mean_initializer = moving_mean_initializer
self.moving_variance_initializer = moving_variance_initializer
self.beta_regularizer = beta_regularizer
self.gamma_regularizer = gamma_regularizer
self.renorm = renorm
self.fused = fused
if self.fused and renorm:
raise ValueError(
'Batch renorm is currently not supported with fused batch norm.')
if self.fused and (beta_regularizer is not None or
gamma_regularizer is not None):
raise ValueError('Regularizers are not currently '
'supported for fused batch norm.')
if renorm:
renorm_clipping = renorm_clipping or {}
keys = ['rmax', 'rmin', 'dmax']
if set(renorm_clipping) - set(keys):
raise ValueError('renorm_clipping %s contains keys not in %s' %
(renorm_clipping, keys))
self.renorm_clipping = renorm_clipping
self.renorm_momentum = renorm_momentum
def __init__(self, value, decay,
truediv=True,
collections=None,
reduction_indices=None,
name=None):
self.value = value
self.reduction_indices = reduction_indices or [0]
eps = 1e-8
if truediv:
div = math_ops.truediv
else:
div = math_ops.div
if collections is None:
collections = [ops.GraphKeys.VARIABLES]
value_shape = value.get_shape().as_list()
shape = []
for dim in range(len(value_shape)):
if dim in self.reduction_indices:
shape.append(1)
else:
shape.append(value_shape[dim])
with variable_scope.variable_op_scope(
[value, decay], name, "MomentTracker") as scope:
mean_x_weight_var = variable_scope.get_variable("mean_x_weight", trainable=False, collections=collections,
initializer=init_ops.zeros_initializer(shape, dtype=value.dtype))
variance_x_weight_var = variable_scope.get_variable("variance_x_weight", trainable=False,
collections=collections, initializer=init_ops.zeros_initializer(shape, dtype=value.dtype))
weight_var = variable_scope.get_variable("weight", trainable=False, collections=collections,
initializer=init_ops.zeros_initializer([1], dtype=tf.float32))
self.tracked_mean = div(mean_x_weight_var, weight_var + eps)
self.tracked_variance = div(variance_x_weight_var, weight_var + eps)
self.batch_mean, self.batch_variance = tf.nn.moments(self.value, axes=self.reduction_indices,
shift=self.tracked_mean, keep_dims=True)
mean_numerator = assign_moving_average(mean_x_weight_var, self.batch_mean, decay)
variance_numerator = assign_moving_average(variance_x_weight_var, self.batch_variance, decay)
denominator = assign_moving_average(weight_var, 1.0, decay)
self.update_mean = div(mean_numerator, denominator + eps, name=scope.name)
self.update_variance = div(variance_numerator, denominator + eps, name=scope.name)
def create_variables_and_ops(self, table, variable_name, num_hosts,
table_config, table_variables,
load_parameters_ops, retrieve_parameters_ops):
optimizer_name = 'Adam'
m_initializer = init_ops.zeros_initializer()
m_variables = _create_partitioned_variables(
name='%s/%s/m' % (variable_name, optimizer_name),
num_hosts=num_hosts,
vocabulary_size=table_config.vocabulary_size,
embedding_dimension=table_config.dimension,
collections=[ops.GraphKeys.GLOBAL_VARIABLES],
initializer=m_initializer)
v_initializer = init_ops.zeros_initializer()
v_variables = _create_partitioned_variables(
name='%s/%s/v' % (variable_name, optimizer_name),
num_hosts=num_hosts,
vocabulary_size=table_config.vocabulary_size,
embedding_dimension=table_config.dimension,
collections=[ops.GraphKeys.GLOBAL_VARIABLES],
initializer=v_initializer)
self._table_to_m_variables_dict[table] = m_variables
self._table_to_v_variables_dict[table] = v_variables
for host_id, table_variable, m_variable, v_variable in (zip(
range(num_hosts), table_variables,
m_variables, v_variables)):
with ops.colocate_with(table_variable):
load_parameters_op = (
tpu_ops.load_tpu_embedding_adam_parameters(
parameters=table_variable,
momenta=m_variable,
velocities=v_variable,
table_name=table,
num_shards=num_hosts,
shard_id=host_id))
retrieved_table, retrieved_m, retrieved_v = (
tpu_ops.retrieve_tpu_embedding_adam_parameters(
table_name=table,
num_shards=num_hosts,
shard_id=host_id))
retrieve_parameters_op = control_flow_ops.group(
state_ops.assign(table_variable, retrieved_table),
state_ops.assign(m_variable, retrieved_m),
state_ops.assign(v_variable, retrieved_v))
load_parameters_ops.append(load_parameters_op)
retrieve_parameters_ops.append(retrieve_parameters_op)
def _get_or_create_eval_step():
"""Gets or creates the eval step `Tensor`.
Returns:
A `Tensor` representing a counter for the evaluation step.
Raises:
ValueError: If multiple `Tensors` have been added to the
`tf.GraphKeys.EVAL_STEP` collection.
"""
graph = ops.get_default_graph()
eval_steps = graph.get_collection(ops.GraphKeys.EVAL_STEP)
if len(eval_steps) == 1:
return eval_steps[0]
elif len(eval_steps) > 1:
raise ValueError('Multiple tensors added to tf.GraphKeys.EVAL_STEP')
else:
counter = variable_scope.get_variable(
'eval_step',
shape=[],
dtype=dtypes.int64,
initializer=init_ops.zeros_initializer(),
trainable=False,
collections=[ops.GraphKeys.LOCAL_VARIABLES, ops.GraphKeys.EVAL_STEP])
return counter
def test_multiple_random_accumulating_updates_results_in_right_dist(self):
# Accumulate the updates in a new variable. Resultant
# histogram should be uniform. Use only 3 bins because with many bins it
# would be unlikely that all would be close to 1/n. If someone ever wants
# to test that, it would be better to check that the cdf was linear.
value_range = [1.0, 4.14159]
with self.test_session() as sess:
values = array_ops.placeholder(dtypes.float32, shape=[4, 4, 4])
hist = histogram_ops.histogram_fixed_width(
values, value_range, nbins=3, dtype=dtypes.int64)
hist_accum = variables.Variable(init_ops.zeros_initializer()(
[3], dtype=dtypes.int64))
hist_accum = hist_accum.assign_add(hist)
variables.global_variables_initializer().run()
for _ in range(100):
# Map the rv: U[0, 1] --> U[value_range[0], value_range[1]].
values_arr = (
value_range[0] +
(value_range[1] - value_range[0]) * self.rng.rand(4, 4, 4))
hist_accum_arr = sess.run(hist_accum, feed_dict={values: values_arr})
pmf = hist_accum_arr / float(hist_accum_arr.sum())
np.testing.assert_allclose(1 / 3, pmf, atol=0.02)
def testInitFromNonInitializer(self):
with self.test_session() as sess:
# Test various dtypes with zeros initializer as following:
types = [
dtypes.int8, dtypes.uint8, dtypes.int16, dtypes.uint16, dtypes.int32,
dtypes.int64, dtypes.bool
]
# Use different varibale_name to distinguish various dtypes
for (i, dtype) in enumerate(types):
x = variable_scope.get_variable(
name="x%d" % i,
shape=(3, 4),
dtype=dtype,
partitioner=axis0_into2_partitioner)
y = variable_scope.get_variable(
name="y%d" % i,
shape=(6, 4),
dtype=dtype,
partitioner=axis0_into2_partitioner,
initializer=init_ops.zeros_initializer(dtype=dtype))
variables_lib.global_variables_initializer().run()
# x and y would become var list after partition
val_x = sess.run(list(x))
val_y = sess.run(list(y))
self.assertAllEqual(val_x, val_y)
def _create_global_step(self, graph):
"""Creates a global step suitable for TPUs.
Args:
graph: The graph in which to create the global step.
Returns:
A global step `Tensor`.
Raises:
ValueError: if the global step tensor is already defined.
"""
graph = graph or ops.get_default_graph()
if training.get_global_step(graph) is not None:
raise ValueError('"global_step" already exists.')
# Create in proper graph and base name_scope.
with graph.as_default() as g, g.name_scope(None):
return variable_scope.get_variable(
ops.GraphKeys.GLOBAL_STEP,
shape=[],
dtype=dtypes.int32,
initializer=init_ops.zeros_initializer(),
trainable=False,
use_resource=True,
collections=[ops.GraphKeys.GLOBAL_VARIABLES,
ops.GraphKeys.GLOBAL_STEP])
def model_fn(features, labels, mode):
_ = labels
step = training.get_global_step()
w = variable_scope.get_variable(
'w',
shape=[],
initializer=init_ops.zeros_initializer(),
dtype=dtypes.int64)
if estimator_lib.ModeKeys.TRAIN == mode:
# to consume features, we have control dependency
with ops.control_dependencies([features]):
step_inc = state_ops.assign_add(training.get_global_step(), 1)
with ops.control_dependencies([step_inc]):
assign_w_to_step_plus_2 = w.assign(step + 2)
return estimator_lib.EstimatorSpec(
mode,
loss=constant_op.constant(3.),
train_op=assign_w_to_step_plus_2)
if estimator_lib.ModeKeys.EVAL == mode:
# to consume features, we have control dependency
with ops.control_dependencies([features]):
loss = constant_op.constant(5.)
return estimator_lib.EstimatorSpec(
mode,
loss=loss,
# w is constant in each step, so the mean.
# w = 0 if step==0 else step+2
eval_metric_ops={'mean_of_const': metrics_lib.mean(w)})
def apply_gradients(self, grads_and_vars, global_step=None, name=None):
gradients = []
# Number of stale gradients.
stale_counter = variable_scope.get_variable(
"stale_counter", [],
initializer=init_ops.zeros_initializer(),
trainable=False)
def _AcceptGradientOp():
with ops.control_dependencies(
[self._opt.apply_gradients(
grads_and_vars, global_step=global_step, name=name)]):
return gen_array_ops.identity(0.0)
def _DropGradientOp():
return gen_array_ops.identity(1.0)
for grad_and_var in grads_and_vars:
grad = grad_and_var[0]
if isinstance(grad, ops.Tensor):
gradients.append(grad)
else:
gradients.append(grad.op)
with ops.control_dependencies(gradients), ops.colocate_with(global_step):
staleness = gen_array_ops.reshape(
global_step - self._local_step, shape=())
conditional_update = stale_counter.assign_add(control_flow_ops.cond(
gen_math_ops.less_equal(staleness, self._staleness),
_AcceptGradientOp, _DropGradientOp))
summary.scalar(
"Gradient staleness percentage",
stale_counter / (math_ops.cast(global_step + 1, dtypes.float32)))
return conditional_update
def __init__(self,
filters,
kernel_size,
strides=(1, 1),
padding='valid',
data_format='channels_last',
dilation_rate=(1, 1),
activation=None,
use_bias=True,
kernel_initializer=None,
bias_initializer=init_ops.zeros_initializer(),
kernel_regularizer=None,
bias_regularizer=None,
activity_regularizer=None,
trainable=True,
name=None,
**kwargs):
super(MaskedConv2D, self).__init__(
rank=2,
filters=filters,
kernel_size=kernel_size,
strides=strides,
padding=padding,
data_format=data_format,
dilation_rate=dilation_rate,
activation=activation,
use_bias=use_bias,
kernel_initializer=kernel_initializer,
bias_initializer=bias_initializer,
kernel_regularizer=kernel_regularizer,
bias_regularizer=bias_regularizer,
activity_regularizer=activity_regularizer,
trainable=trainable,
name=name,
**kwargs)
def testInitialValueComesFromCheckpoint(self):
checkpoint_dir = self.get_temp_dir()
with self.test_session() as session:
v1, _, _, _ = _create_checkpoints(session, checkpoint_dir)
# New graph and session.
with ops.Graph().as_default() as g:
with self.test_session(graph=g) as session:
with variable_scope.variable_scope(
"some_scope", initializer=init_ops.zeros_initializer()):
my1 = variable_scope.get_variable("my1", [1, 10])
# At this point, my1.initialized_value() will add ops that reference
# the zeros initializer of my1.
before = variables.Variable(my1.initialized_value(), name="before")
checkpoint_utils.init_from_checkpoint(checkpoint_dir, {"var1": my1})
# At this point, my1.initialized_value() will add ops that reference
# the newly set initializer of my1.
after = variables.Variable(my1.initialized_value(), name="after")
session.run(variables.global_variables_initializer())
self.assertAllEqual(session.run(my1), v1)
self.assertAllEqual(session.run(my1.initialized_value()), v1)
self.assertAllClose(session.run(before), [[0.0] * 10])
self.assertAllClose(session.run(after), v1)
with self.assertRaises(AssertionError):
self.assertAllClose(session.run(before), session.run(after))
def variable_scoped_function_no_return_value(trainable=True):
# defun cannot compile functions that return non-Tensor objects
_ = variable_scope.get_variable(
"dummy",
shape=[1],
trainable=trainable,
initializer=init_ops.zeros_initializer())
def testZerosInitializer(self):
with self.test_session(use_gpu=True):
shape = [2, 3]
x = variable_scope.get_variable(
"x", shape=shape, initializer=init_ops.zeros_initializer())
x.initializer.run()
self.assertAllEqual(x.eval(), np.zeros(shape))
def testVariableInput(self):
with self.test_session():
v = variable_scope.get_variable(
'X', initializer=init_ops.zeros_initializer(), shape=(1, 1))
x = core_layers.Dense(1)(v)
variables.global_variables_initializer().run()
self.assertAllEqual(x.eval(), [[0.0]])
def testInitialValueComesFromCheckpoint(self):
checkpoint_dir = self.get_temp_dir()
with self.test_session() as session:
v1, _, _, _ = _create_checkpoints(session, checkpoint_dir)
# New graph and session.
with ops.Graph().as_default() as g:
with self.test_session(graph=g) as session:
with variable_scope.variable_scope(
"some_scope", initializer=init_ops.zeros_initializer()):
my1 = variable_scope.get_variable("my1", [1, 10])
before = my1.initialized_value()
checkpoint_utils.init_from_checkpoint(checkpoint_dir, {"var1": my1})
after = my1.initialized_value()
self.assertAllEqual(session.run(before), [[0.0] * 10])
self.assertAllEqual(session.run(after), v1)
session.run(variables.global_variables_initializer())
self.assertAllEqual(session.run(my1), v1)
self.assertAllEqual(session.run(my1.initialized_value()), v1)
self.assertAllClose(session.run(before), v1)
self.assertAllClose(session.run(after), v1)
with self.assertRaises(AssertionError):
self.assertAllClose(v1, [[0.0] * 10])
def build(self, inputs_shape):
if inputs_shape[1].value is None:
raise ValueError("Expected inputs.shape[-1] to be known, saw shape: %s"
% inputs_shape)
input_depth = inputs_shape[1].value
self._gate_kernel = self.add_variable(
"gates/%s" % _WEIGHTS_VARIABLE_NAME,
shape=[input_depth + self._num_units, 2 * self._num_units],
initializer=self._kernel_initializer)
self._gate_bias = self.add_variable(
"gates/%s" % _BIAS_VARIABLE_NAME,
shape=[2 * self._num_units],
initializer=(
self._bias_initializer
if self._bias_initializer is not None
else init_ops.constant_initializer(1.0, dtype=self.dtype)))
self._candidate_kernel = self.add_variable(
"candidate/%s" % _WEIGHTS_VARIABLE_NAME,
shape=[input_depth + self._num_units, self._num_units],
initializer=self._kernel_initializer)
self._candidate_bias = self.add_variable(
"candidate/%s" % _BIAS_VARIABLE_NAME,
shape=[self._num_units],
initializer=(
self._bias_initializer
if self._bias_initializer is not None
else init_ops.zeros_initializer(dtype=self.dtype)))
self.built = True
def __init__(self, units,
activation=None,
use_bias=True,
kernel_initializer=None,
bias_initializer=init_ops.zeros_initializer(),
kernel_regularizer=None,
bias_regularizer=None,
activity_regularizer=None,
kernel_constraint=None,
bias_constraint=None,
trainable=True,
name=None,
**kwargs):
super(Dense, self).__init__(units=units,
activation=activation,
use_bias=use_bias,
kernel_initializer=kernel_initializer,
bias_initializer=bias_initializer,
kernel_regularizer=kernel_regularizer,
bias_regularizer=bias_regularizer,
activity_regularizer=activity_regularizer,
kernel_constraint=kernel_constraint,
bias_constraint=bias_constraint,
trainable=trainable,
name=name,
**kwargs)
def __init__(self, units,
activation=None,
use_bias=True,
kernel_initializer=None,
bias_initializer=init_ops.zeros_initializer(),
kernel_regularizer=None,
bias_regularizer=None,
activity_regularizer=None,
kernel_constraint=None,
bias_constraint=None,
trainable=True,
name=None,
**kwargs):
super(Dense, self).__init__(trainable=trainable, name=name, **kwargs)
self.units = units
self.activation = activation
self.use_bias = use_bias
self.kernel_initializer = kernel_initializer
self.bias_initializer = bias_initializer
self.kernel_regularizer = kernel_regularizer
self.bias_regularizer = bias_regularizer
self.activity_regularizer = activity_regularizer
self.kernel_constraint = kernel_constraint
self.bias_constraint = bias_constraint
self.input_spec = base.InputSpec(min_ndim=2)
def create_global_step(graph=None):
"""Create global step tensor in graph.
Args:
graph: The graph in which to create the global step. If missing, use default
graph.
Returns:
Global step tensor.
Raises:
ValueError: if global step key is already defined.
"""
graph = ops.get_default_graph() if graph is None else graph
if get_global_step(graph) is not None:
raise ValueError('"global_step" already exists.')
# Create in proper graph and base name_scope.
with graph.as_default() as g, g.name_scope(None):
collections = [ops.GraphKeys.GLOBAL_VARIABLES, ops.GraphKeys.GLOBAL_STEP]
return variable(
ops.GraphKeys.GLOBAL_STEP,
shape=[],
dtype=dtypes.int64,
initializer=init_ops.zeros_initializer(),
trainable=False,
collections=collections)
def joint_weighted_sum_from_feature_columns(columns_to_tensors,
feature_columns,
num_outputs,
weight_collections=None,
trainable=True,
scope=None):
"""A restricted linear prediction builder based on FeatureColumns.
As long as all feature columns are unweighted sparse columns this computes the
prediction of a linear model which stores all weights in a single variable.
Args:
columns_to_tensors: A mapping from feature column to tensors. 'string' key
means a base feature (not-transformed). It can have FeatureColumn as a
key too. That means that FeatureColumn is already transformed by input
pipeline. For example, `inflow` may have handled transformations.
feature_columns: A set containing all the feature columns. All items in the
set should be instances of classes derived from FeatureColumn.
num_outputs: An integer specifying number of outputs. Default value is 1.
weight_collections: List of graph collections to which weights are added.
trainable: If `True` also add variables to the graph collection
`GraphKeys.TRAINABLE_VARIABLES` (see tf.Variable).
scope: Optional scope for variable_scope.
Returns:
A tuple containing:
* A Tensor which represents predictions of a linear model.
* A list of Variables storing the weights.
* A Variable which is used for bias.
Raises:
ValueError: if FeatureColumn cannot be used for linear predictions.
"""
check_feature_columns(feature_columns)
with variable_scope.variable_scope(
scope,
default_name='joint_weighted_sum_from_feature_columns',
values=columns_to_tensors.values()):
transformer = _Transformer(columns_to_tensors)
embedding_lookup_arguments = []
for column in sorted(set(feature_columns), key=lambda x: x.key):
transformed_tensor = transformer.transform(column)
try:
embedding_lookup_arguments.append(
column._wide_embedding_lookup_arguments(
transformed_tensor)) # pylint: disable=protected-access
except NotImplementedError:
raise NotImplementedError(
'Real-valued columns are not supported. '
'Use weighted_sum_from_feature_columns '
'instead, or bucketize these columns.')
variable, predictions_no_bias = _create_joint_embedding_lookup(
columns_to_tensors, embedding_lookup_arguments, num_outputs,
trainable, weight_collections)
bias = contrib_variables.model_variable(
'bias_weight',
shape=[num_outputs],
initializer=init_ops.zeros_initializer(),
trainable=trainable,
collections=_add_variable_collection(weight_collections))
_log_variable(bias)
predictions = nn_ops.bias_add(predictions_no_bias, bias)
return predictions, variable, bias
def alexnet_v2(inputs,
num_classes=1000,
is_training=True,
dropout_keep_prob=0.5,
spatial_squeeze=True,
scope='alexnet_v2'):
"""AlexNet version 2.
Described in: http://arxiv.org/pdf/1404.5997v2.pdf
Parameters from:
github.com/akrizhevsky/cuda-convnet2/blob/master/layers/
layers-imagenet-1gpu.cfg
Note: All the fully_connected layers have been transformed to conv2d layers.
To use in classification mode, resize input to 224x224. To use in fully
convolutional mode, set spatial_squeeze to false.
The LRN layers have been removed and change the initializers from
random_normal_initializer to xavier_initializer.
Args:
inputs: a tensor of size [batch_size, height, width, channels].
num_classes: number of predicted classes.
is_training: whether or not the model is being trained.
dropout_keep_prob: the probability that activations are kept in the dropout
layers during training.
spatial_squeeze: whether or not should squeeze the spatial dimensions of the
outputs. Useful to remove unnecessary dimensions for classification.
scope: Optional scope for the variables.
Returns:
the last op containing the log predictions and end_points dict.
"""
with variable_scope.variable_scope(scope, 'alexnet_v2', [inputs]) as sc:
end_points_collection = sc.original_name_scope + '_end_points'
# Collect outputs for conv2d, fully_connected and max_pool2d.
with arg_scope(
[layers.conv2d, layers_lib.fully_connected, layers_lib.max_pool2d],
outputs_collections=[end_points_collection]):
net = layers.conv2d(inputs,
64, [11, 11],
4,
padding='VALID',
scope='conv1')
net = layers_lib.max_pool2d(net, [3, 3], 2, scope='pool1')
net = layers.conv2d(net, 192, [5, 5], scope='conv2')
net = layers_lib.max_pool2d(net, [3, 3], 2, scope='pool2')
net = layers.conv2d(net, 384, [3, 3], scope='conv3')
net = layers.conv2d(net, 384, [3, 3], scope='conv4')
net = layers.conv2d(net, 256, [3, 3], scope='conv5')
net = layers_lib.max_pool2d(net, [3, 3], 2, scope='pool5')
# Use conv2d instead of fully_connected layers.
with arg_scope(
[layers.conv2d],
weights_initializer=trunc_normal(0.005),
biases_initializer=init_ops.constant_initializer(0.1)):
net = layers.conv2d(net,
4096, [5, 5],
padding='VALID',
scope='fc6')
net = layers_lib.dropout(net,
dropout_keep_prob,
is_training=is_training,
scope='dropout6')
net = layers.conv2d(net, 4096, [1, 1], scope='fc7')
net = layers_lib.dropout(net,
dropout_keep_prob,
is_training=is_training,
scope='dropout7')
net = layers.conv2d(
net,
num_classes, [1, 1],
activation_fn=None,
normalizer_fn=None,
biases_initializer=init_ops.zeros_initializer(),
scope='fc8')
# Convert end_points_collection into a end_point dict.
end_points = utils.convert_collection_to_dict(
end_points_collection)
if spatial_squeeze:
net = array_ops.squeeze(net, [1, 2], name='fc8/squeezed')
end_points[sc.name + '/fc8'] = net
return net, end_points
def build(self, input_shape):
self.my_var = self.add_variable(
'my_var', [2, 2],
initializer=init_ops.zeros_initializer())
def moving_mean_variance(value, decay, collections=None, name=None):
"""Compute exponentially weighted moving {mean,variance} of a streaming value.
The exponentially-weighting moving `mean_var` and `variance_var` are updated
by `value` according to the following recurrence:
```python
variance_var = decay * (variance_var + (1-decay) * (value - mean_var)**2)
mean_var = decay * mean_var + (1 - decay) * value
```
Note: `mean_var` is updated *after* `variance_var`, i.e., `variance_var` uses
the lag-`1` mean.
For derivation justification, see equation 143 of:
T. Finch, Feb 2009. "Incremental calculation of weighted mean and variance".
http://people.ds.cam.ac.uk/fanf2/hermes/doc/antiforgery/stats.pdf
Unlike `assign_moving_mean_variance`, this function handles
variable creation.
Args:
value: `float`-like `Tensor`. Same shape as `mean_var` and `variance_var`.
decay: A `float`-like `Tensor`. The moving mean decay. Typically close to
`1.`, e.g., `0.999`.
collections: Python list of graph-collections keys to which the internal
variables `mean_var` and `variance_var` are added.
Default value is `[GraphKeys.GLOBAL_VARIABLES]`.
name: Optional name of the returned operation.
Returns:
mean_var: `Variable` representing the `value`-updated exponentially weighted
moving mean.
variance_var: `Variable` representing the `value`-updated
exponentially weighted moving variance.
Raises:
TypeError: if `value_var` does not have float type `dtype`.
TypeError: if `value`, `decay` have different `base_dtype`.
"""
if collections is None:
collections = [ops.GraphKeys.GLOBAL_VARIABLES]
with variable_scope.variable_scope(name, "moving_mean_variance",
[value, decay]):
value = ops.convert_to_tensor(value, name="value")
base_dtype = value.dtype.base_dtype
if not base_dtype.is_floating:
raise TypeError(
"value.base_dtype({}) does not have float type `dtype`.".
format(base_dtype.name))
decay = ops.convert_to_tensor(decay, dtype=base_dtype, name="decay")
variance_var = variable_scope.get_variable(
"moving_variance",
shape=value.shape,
dtype=value.dtype,
initializer=init_ops.zeros_initializer(),
trainable=False,
collections=collections)
mean_var = variable_scope.get_variable(
"moving_mean",
shape=value.shape,
dtype=value.dtype,
initializer=init_ops.zeros_initializer(),
trainable=False,
collections=collections)
return assign_moving_mean_variance(mean_var, variance_var, value,
decay)
def conv2d(inputs,
num_outputs,
kernel_size,
stride=1,
padding='SAME',
data_format=None,
rate=1,
activation_fn=nn.relu,
normalizer_fn=None,
normalizer_params=None,
weights_initializer=initializers.xavier_initializer(),
weights_regularizer=None,
biases_initializer=init_ops.zeros_initializer(),
biases_regularizer=None,
reuse=None,
variables_collections=None,
outputs_collections=None,
trainable=True,
scope=None,
quantizer=None,
weight_quantizer = None):
""" function call from slim library.
"""
if data_format not in [None, 'NWC', 'NCW', 'NHWC', 'NCHW', 'NDHWC', 'NCDHW']:
raise ValueError('Invalid data_format: %r' % (data_format,))
layer_variable_getter = layers._build_variable_getter(
{'bias': 'biases', 'kernel': 'weights'})
with variable_scope.variable_scope(
scope, 'Conv', [inputs], reuse=reuse,
custom_getter=layer_variable_getter) as sc:
inputs = ops.convert_to_tensor(inputs)
input_rank = inputs.get_shape().ndims
if input_rank == 4:
layer_class = QConv2D #convolutional.Conv2D
else:
raise ValueError('Convolution not supported for input with rank',
input_rank)
df = ('channels_first' if data_format and data_format.startswith('NC')
else 'channels_last')
layer = layer_class(filters=num_outputs,
kernel_size=kernel_size,
strides=stride,
padding=padding,
data_format=df,
dilation_rate=rate,
activation=None,
use_bias=not normalizer_fn and biases_initializer,
kernel_initializer=weights_initializer,
bias_initializer=biases_initializer,
kernel_regularizer=weights_regularizer,
bias_regularizer=biases_regularizer,
activity_regularizer=None,
trainable=trainable,
name=sc.name,
dtype=inputs.dtype.base_dtype,
_scope=sc,
_reuse=reuse,
quantizer = quantizer,
weight_quantizer=weight_quantizer)
outputs = layer.apply(inputs)
# Add variables to collections.
layers._add_variable_to_collections(layer.kernel, variables_collections, 'weights')
if layer.use_bias:
layers._add_variable_to_collections(layer.bias, variables_collections, 'biases')
if normalizer_fn is not None:
normalizer_params = normalizer_params or {}
outputs = normalizer_fn(outputs, **normalizer_params)
if quantizer is not None: # quantize after normalization
outputs = quantizer.quantize(outputs)
if activation_fn is not None:
outputs = activation_fn(outputs)
if quantizer is not None: # quantize after activation
outputs = quantizer.quantize(outputs)
return slim_utils.collect_named_outputs(outputs_collections,
sc.original_name_scope, outputs)
def weighted_sum_from_feature_columns(columns_to_tensors,
feature_columns,
num_outputs,
weight_collections=None,
trainable=True,
scope=None):
"""A tf.contrib.layer style linear prediction builder based on FeatureColumns.
Generally a single example in training data is described with feature columns.
This function generates weighted sum for each num_outputs. Weighted sum refers
to logits in classification problems. It refers to prediction itself for
linear regression problems.
Example:
```
# Building model for training
feature_columns = (
real_valued_column("my_feature1"),
...
)
columns_to_tensor = tf.parse_example(...)
logits = weighted_sum_from_feature_columns(
columns_to_tensors=columns_to_tensor,
feature_columns=feature_columns,
num_outputs=1)
loss = tf.nn.sigmoid_cross_entropy_with_logits(labels=labels,
logits=logits)
```
Args:
columns_to_tensors: A mapping from feature column to tensors. 'string' key
means a base feature (not-transformed). It can have FeatureColumn as a
key too. That means that FeatureColumn is already transformed by input
pipeline. For example, `inflow` may have handled transformations.
feature_columns: A set containing all the feature columns. All items in the
set should be instances of classes derived from FeatureColumn.
num_outputs: An integer specifying number of outputs. Default value is 1.
weight_collections: List of graph collections to which weights are added.
trainable: If `True` also add variables to the graph collection
`GraphKeys.TRAINABLE_VARIABLES` (see tf.Variable).
scope: Optional scope for variable_scope.
Returns:
A tuple containing:
* A Tensor which represents predictions of a linear model.
* A dictionary which maps feature_column to corresponding Variable.
* A Variable which is used for bias.
Raises:
ValueError: if FeatureColumn cannot be used for linear predictions.
"""
check_feature_columns(feature_columns)
with variable_scope.variable_scope(
scope,
default_name='weighted_sum_from_feature_columns',
values=columns_to_tensors.values()):
output_tensors = []
column_to_variable = dict()
transformer = _Transformer(columns_to_tensors)
# pylint: disable=protected-access
for column in sorted(set(feature_columns), key=lambda x: x.key):
transformed_tensor = transformer.transform(column)
try:
embedding_lookup_arguments = column._wide_embedding_lookup_arguments(
transformed_tensor)
variable, predictions = _create_embedding_lookup(
column, columns_to_tensors, embedding_lookup_arguments,
num_outputs, trainable, weight_collections)
except NotImplementedError:
with variable_scope.variable_scope(
None,
default_name=column.name,
values=columns_to_tensors.values()):
tensor = column._to_dense_tensor(transformed_tensor)
tensor = fc._reshape_real_valued_tensor(
tensor, 2, column.name)
variable = [
contrib_variables.model_variable(
name='weight',
shape=[tensor.get_shape()[1], num_outputs],
initializer=init_ops.zeros_initializer(),
trainable=trainable,
collections=weight_collections)
]
predictions = math_ops.matmul(tensor,
variable[0],
name='matmul')
except ValueError as ee:
raise ValueError(
'Error creating weighted sum for column: {}.\n'
'{}'.format(column.name, ee))
output_tensors.append(
array_ops.reshape(predictions, shape=(-1, num_outputs)))
column_to_variable[column] = variable
_log_variable(variable)
_maybe_restore_from_checkpoint(column._checkpoint_path(), variable)
# pylint: enable=protected-access
predictions_no_bias = math_ops.add_n(output_tensors)
bias = contrib_variables.model_variable(
'bias_weight',
shape=[num_outputs],
initializer=init_ops.zeros_initializer(),
trainable=trainable,
collections=_add_variable_collection(weight_collections))
_log_variable(bias)
predictions = nn_ops.bias_add(predictions_no_bias, bias)
return predictions, column_to_variable, bias
