def _create_or_restore_slot_variable(
self, slot_variable_position, slot_name, variable):
"""Restore a slot variable's value, possibly creating it.
Called when a variable which has an associated slot variable is created or
restored. When executing eagerly, we create the slot variable with a
restoring initializer.
No new variables are created when graph building. Instead,
_restore_slot_variable catches these after normal creation and adds restore
ops to the graph. This method is nonetheless important when graph building
for the case when a slot variable has already been created but `variable`
has just been added to a dependency graph (causing us to realize that the
slot variable needs to be restored).
Args:
slot_variable_position: A `trackable._CheckpointPosition` object
indicating the slot variable `Trackable` object to be restored.
slot_name: The name of this `Optimizer`'s slot to restore into.
variable: The variable object this slot is being created for.
"""
variable_key = _var_key(variable)
slot_dict = self._slots.get(variable_key, {})
slot_variable = slot_dict.get(slot_name, None)
if (slot_variable is None and context.executing_eagerly() and
slot_variable_position.is_simple_variable()
# Defer slot variable creation if there is an active variable creator
# scope. Generally we'd like to eagerly create/restore slot variables
# when possible, but this may mean that scopes intended to catch
# `variable` also catch its eagerly created slot variable
# unintentionally (specifically make_template would add a dependency on
# a slot variable if not for this case). Deferring is mostly harmless
# (aside from double initialization), and makes variable creator scopes
# behave the same way they do when graph building.
and not ops.get_default_graph()._variable_creator_stack): # pylint: disable=protected-access
initializer = trackable.CheckpointInitialValue(
checkpoint_position=slot_variable_position)
slot_variable = self.add_slot(
var=variable,
initializer=initializer,
slot_name=slot_name)
# Slot variables are not owned by any one object (because we don't want to
# save the slot variable if the optimizer is saved without the non-slot
# variable, or if the non-slot variable is saved without the optimizer;
# it's a dependency hypergraph with edges of the form (optimizer, non-slot
# variable, variable)). So we don't _track_ slot variables anywhere, and
# instead special-case this dependency and otherwise pretend it's a normal
# graph.
if slot_variable is not None:
# If we've either made this slot variable, or if we've pulled out an
# existing slot variable, we should restore it.
slot_variable_position.restore(slot_variable)
else:
# We didn't make the slot variable. Defer restoring until it gets created
# normally. We keep a list rather than the one with the highest restore
# UID in case slot variables have their own dependencies, in which case
# those could differ between restores.
self._deferred_slot_restorations.setdefault(
slot_name, {}).setdefault(variable_key, []).append(
slot_variable_position)
"""
variable_key = _var_key(variable)
slot_dict = self._slots.get(variable_key, {})
slot_variable = slot_dict.get(slot_name, None)
if (slot_variable is None and context.executing_eagerly() and
slot_variable_position.is_simple_variable()
# Defer slot variable creation if there is an active variable creator
# scope. Generally we'd like to eagerly create/restore slot variables
# when possible, but this may mean that scopes intended to catch
# `variable` also catch its eagerly created slot variable
# unintentionally (specifically make_template would add a dependency on
# a slot variable if not for this case). Deferring is mostly harmless
# (aside from double initialization), and makes variable creator scopes
# behave the same way they do when graph building.
and not ops.get_default_graph()._variable_creator_stack): # pylint: disable=protected-access
initializer = trackable.CheckpointInitialValue(
checkpoint_position=slot_variable_position)
slot_variable = self.add_slot(
var=variable,
initializer=initializer,
slot_name=slot_name)
# Slot variables are not owned by any one object (because we don't want to
# save the slot variable if the optimizer is saved without the non-slot
# variable, or if the non-slot variable is saved without the optimizer;
# it's a dependency hypergraph with edges of the form (optimizer, non-slot
# variable, variable)). So we don't _track_ slot variables anywhere, and
# instead special-case this dependency and otherwise pretend it's a normal
# graph.
if slot_variable is not None:
# If we've either made this slot variable, or if we've pulled out an
# existing slot variable, we should restore it.
slot_variable_position.restore(slot_variable)
