Optimizer that implements the Adadelta algorithm.
Inherits From: Optimizer
tf.train.AdadeltaOptimizer( learning_rate=0.001, rho=0.95, epsilon=1e-08, use_locking=False, name='Adadelta' )
See M. D. Zeiler (pdf)
Args | |
---|---|
learning_rate | A Tensor or a floating point value. The learning rate. To match the exact form in the original paper use 1.0. |
rho | A Tensor or a floating point value. The decay rate. |
epsilon | A Tensor or a floating point value. A constant epsilon used to better conditioning the grad update. |
use_locking | If True use locks for update operations. |
name | Optional name prefix for the operations created when applying gradients. Defaults to "Adadelta". |
apply_gradients
apply_gradients( grads_and_vars, global_step=None, name=None )
Apply gradients to variables.
This is the second part of minimize()
. It returns an Operation
that applies gradients.
Args | |
---|---|
grads_and_vars | List of (gradient, variable) pairs as returned by compute_gradients() . |
global_step | Optional Variable to increment by one after the variables have been updated. |
name | Optional name for the returned operation. Default to the name passed to the Optimizer constructor. |
Returns | |
---|---|
An Operation that applies the specified gradients. If global_step was not None, that operation also increments global_step . |
Raises | |
---|---|
TypeError | If grads_and_vars is malformed. |
ValueError | If none of the variables have gradients. |
RuntimeError | If you should use _distributed_apply() instead. |
compute_gradients
compute_gradients( loss, var_list=None, gate_gradients=GATE_OP, aggregation_method=None, colocate_gradients_with_ops=False, grad_loss=None )
Compute gradients of loss
for the variables in var_list
.
This is the first part of minimize()
. It returns a list of (gradient, variable) pairs where "gradient" is the gradient for "variable". Note that "gradient" can be a Tensor
, an IndexedSlices
, or None
if there is no gradient for the given variable.
Args | |
---|---|
loss | A Tensor containing the value to minimize or a callable taking no arguments which returns the value to minimize. When eager execution is enabled it must be a callable. |
var_list | Optional list or tuple of tf.Variable to update to minimize loss . Defaults to the list of variables collected in the graph under the key GraphKeys.TRAINABLE_VARIABLES . |
gate_gradients | How to gate the computation of gradients. Can be GATE_NONE , GATE_OP , or GATE_GRAPH . |
aggregation_method | Specifies the method used to combine gradient terms. Valid values are defined in the class AggregationMethod . |
colocate_gradients_with_ops | If True, try colocating gradients with the corresponding op. |
grad_loss | Optional. A Tensor holding the gradient computed for loss . |
Returns | |
---|---|
A list of (gradient, variable) pairs. Variable is always present, but gradient can be None . |
Raises | |
---|---|
TypeError | If var_list contains anything else than Variable objects. |
ValueError | If some arguments are invalid. |
RuntimeError | If called with eager execution enabled and loss is not callable. |
When eager execution is enabled, gate_gradients
, aggregation_method
, and colocate_gradients_with_ops
are ignored.
get_name
get_name()
get_slot
get_slot( var, name )
Return a slot named name
created for var
by the Optimizer.
Some Optimizer
subclasses use additional variables. For example Momentum
and Adagrad
use variables to accumulate updates. This method gives access to these Variable
objects if for some reason you need them.
Use get_slot_names()
to get the list of slot names created by the Optimizer
.
Args | |
---|---|
var | A variable passed to minimize() or apply_gradients() . |
name | A string. |
Returns | |
---|---|
The Variable for the slot if it was created, None otherwise. |
get_slot_names
get_slot_names()
Return a list of the names of slots created by the Optimizer
.
See get_slot()
.
Returns | |
---|---|
A list of strings. |
minimize
minimize( loss, global_step=None, var_list=None, gate_gradients=GATE_OP, aggregation_method=None, colocate_gradients_with_ops=False, name=None, grad_loss=None )
Add operations to minimize loss
by updating var_list
.
This method simply combines calls compute_gradients()
and apply_gradients()
. If you want to process the gradient before applying them call compute_gradients()
and apply_gradients()
explicitly instead of using this function.
Args | |
---|---|
loss | A Tensor containing the value to minimize. |
global_step | Optional Variable to increment by one after the variables have been updated. |
var_list | Optional list or tuple of Variable objects to update to minimize loss . Defaults to the list of variables collected in the graph under the key GraphKeys.TRAINABLE_VARIABLES . |
gate_gradients | How to gate the computation of gradients. Can be GATE_NONE , GATE_OP , or GATE_GRAPH . |
aggregation_method | Specifies the method used to combine gradient terms. Valid values are defined in the class AggregationMethod . |
colocate_gradients_with_ops | If True, try colocating gradients with the corresponding op. |
name | Optional name for the returned operation. |
grad_loss | Optional. A Tensor holding the gradient computed for loss . |
Returns | |
---|---|
An Operation that updates the variables in var_list . If global_step was not None , that operation also increments global_step . |
Raises | |
---|---|
ValueError | If some of the variables are not Variable objects. |
When eager execution is enabled, loss
should be a Python function that takes no arguments and computes the value to be minimized. Minimization (and gradient computation) is done with respect to the elements of var_list
if not None, else with respect to any trainable variables created during the execution of the loss
function. gate_gradients
, aggregation_method
, colocate_gradients_with_ops
and grad_loss
are ignored when eager execution is enabled.
variables
variables()
A list of variables which encode the current state of Optimizer
.
Includes slot variables and additional global variables created by the optimizer in the current default graph.
Returns | |
---|---|
A list of variables. |
GATE_GRAPH = 2
GATE_NONE = 0
GATE_OP = 1
© 2020 The TensorFlow Authors. All rights reserved.
Licensed under the Creative Commons Attribution License 3.0.
Code samples licensed under the Apache 2.0 License.
https://www.tensorflow.org/versions/r1.15/api_docs/python/tf/train/AdadeltaOptimizer