168 lines
6.6 KiB
Python
168 lines
6.6 KiB
Python
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"""Manages a graph of Trackable objects."""
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# Copyright 2017 The TensorFlow Authors. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# ==============================================================================
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import copy
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import weakref
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from tensorflow.python.checkpoint import save_util_v1
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from tensorflow.python.checkpoint import trackable_view
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from tensorflow.python.trackable import base
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from tensorflow.python.util.tf_export import tf_export
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@tf_export("__internal__.tracking.ObjectGraphView", v1=[])
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class ObjectGraphView(trackable_view.TrackableView):
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"""Gathers and serializes an object graph."""
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def __init__(self, root, attached_dependencies=None):
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"""Configure the graph view.
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Args:
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root: A `Trackable` object whose variables (including the variables of
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dependencies, recursively) should be saved. May be a weak reference.
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attached_dependencies: List of dependencies to attach to the root object.
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Used when saving a Checkpoint with a defined root object. To avoid
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reference cycles, this should use the WeakTrackableReference class.
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"""
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trackable_view.TrackableView.__init__(self, root)
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# ObjectGraphView should never contain a strong reference to root, since it
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# may result in a cycle:
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# root -> deferred dependencies -> CheckpointPosition
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# -> CheckpointRestoreCoordinator -> ObjectGraphView -> root
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self._root_ref = (root if isinstance(root, weakref.ref)
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else weakref.ref(root))
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self._attached_dependencies = attached_dependencies
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def __deepcopy__(self, memo):
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# By default, weak references are not copied, which leads to surprising
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# deepcopy behavior. To fix, we first we copy the object itself, then we
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# make a weak reference to the copy.
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strong_root = self._root_ref()
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if strong_root is not None:
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strong_copy = copy.deepcopy(strong_root, memo)
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memo[id(self._root_ref)] = weakref.ref(strong_copy)
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# super() does not have a __deepcopy__, so we need to re-implement it
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copied = super().__new__(type(self))
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memo[id(self)] = copied
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for key, value in vars(self).items():
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setattr(copied, key, copy.deepcopy(value, memo))
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return copied
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def list_children(self, obj, save_type=base.SaveType.CHECKPOINT, **kwargs):
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"""Returns list of all child trackables attached to obj.
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Args:
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obj: A `Trackable` object.
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save_type: A string, can be 'savedmodel' or 'checkpoint'.
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**kwargs: kwargs to use when retrieving the object's children.
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Returns:
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List of all children attached to the object.
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"""
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children = []
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for name, ref in super(ObjectGraphView,
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self).children(obj, save_type, **kwargs).items():
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children.append(base.TrackableReference(name, ref))
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# GraphView objects may define children of the root object that are not
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# actually attached, e.g. a Checkpoint object's save_counter.
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if obj is self.root and self._attached_dependencies:
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children.extend(self._attached_dependencies)
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return children
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def children(self, obj, save_type=base.SaveType.CHECKPOINT, **kwargs):
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"""Returns all child trackables attached to obj.
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Args:
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obj: A `Trackable` object.
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save_type: A string, can be 'savedmodel' or 'checkpoint'.
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**kwargs: kwargs to use when retrieving the object's children.
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Returns:
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Dictionary of all children attached to the object with name to trackable.
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"""
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children = {}
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for name, ref in self.list_children(obj, **kwargs):
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children[name] = ref
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return children
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@property
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def attached_dependencies(self):
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"""Returns list of dependencies that should be saved in the checkpoint.
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These dependencies are not tracked by root, but are in the checkpoint.
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This is defined when the user creates a Checkpoint with both root and kwargs
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set.
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Returns:
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A list of TrackableReferences.
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"""
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return self._attached_dependencies
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@property
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def root(self):
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if isinstance(self._root_ref, weakref.ref):
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derefed = self._root_ref()
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assert derefed is not None
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return derefed
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else:
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return self._root_ref
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def breadth_first_traversal(self):
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return self._breadth_first_traversal()
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def _breadth_first_traversal(self):
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"""Find shortest paths to all dependencies of self.root."""
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return super(ObjectGraphView, self)._descendants_with_paths()
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def serialize_object_graph(self, saveables_cache=None):
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"""Determine checkpoint keys for variables and build a serialized graph.
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Non-slot variables are keyed based on a shortest path from the root saveable
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to the object which owns the variable (i.e. the one which called
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`Trackable._add_variable` to create it).
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Slot variables are keyed based on a shortest path to the variable being
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slotted for, a shortest path to their optimizer, and the slot name.
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Args:
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saveables_cache: An optional cache storing previously created
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SaveableObjects created for each Trackable. Maps Trackables to a
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dictionary of attribute names to Trackable.
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Returns:
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A tuple of (named_variables, object_graph_proto, feed_additions):
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named_variables: A dictionary mapping names to variable objects.
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object_graph_proto: A TrackableObjectGraph protocol buffer
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containing the serialized object graph and variable references.
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feed_additions: A dictionary mapping from Tensors to values which should
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be fed when saving.
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Raises:
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ValueError: If there are invalid characters in an optimizer's slot names.
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"""
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named_saveable_objects, object_graph_proto, feed_additions, _ = (
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save_util_v1.serialize_object_graph_with_registered_savers(
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self, saveables_cache))
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return named_saveable_objects, object_graph_proto, feed_additions
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def frozen_saveable_objects(self,
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object_map=None,
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to_graph=None,
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call_with_mapped_captures=None):
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"""Creates SaveableObjects with the current object graph frozen."""
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return save_util_v1.frozen_saveables_and_savers(
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self, object_map, to_graph, call_with_mapped_captures)[0]
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