wehub-resource-sync
142 lines
4.9 KiB
Python
142 lines
4.9 KiB
Python
# Copyright 2018 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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"""Utilities related to layer/model functionality."""
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# TODO(b/110718070): Move these functions back to tensorflow/python/keras/utils
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# once __init__ files no longer require all of tf.keras to be imported together.
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import collections
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import weakref
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from tensorflow.python.util import object_identity
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try:
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# typing module is only used for comment type annotations.
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import typing # pylint: disable=g-import-not-at-top, unused-import
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except ImportError:
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pass
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def is_layer(obj):
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"""Implicit check for Layer-like objects."""
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# TODO(b/110718070): Replace with isinstance(obj, base_layer.Layer).
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return hasattr(obj, "_is_layer") and not isinstance(obj, type)
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def has_weights(obj):
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"""Implicit check for Layer-like objects."""
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# TODO(b/110718070): Replace with isinstance(obj, base_layer.Layer).
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has_weight = (hasattr(type(obj), "trainable_weights")
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and hasattr(type(obj), "non_trainable_weights"))
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return has_weight and not isinstance(obj, type)
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class MutationSentinel(object):
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"""Container for tracking whether a property is in a cached state."""
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_in_cached_state = False
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def mark_as(self, value): # type: (MutationSentinel, bool) -> bool
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may_affect_upstream = (value != self._in_cached_state)
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self._in_cached_state = value
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return may_affect_upstream
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@property
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def in_cached_state(self):
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return self._in_cached_state
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class AttributeSentinel(object):
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"""Container for managing attribute cache state within a Layer.
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The cache can be invalidated either on an individual basis (for instance when
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an attribute is mutated) or a layer-wide basis (such as when a new dependency
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is added).
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"""
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def __init__(self, always_propagate=False):
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self._parents = weakref.WeakSet()
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self.attributes = collections.defaultdict(MutationSentinel)
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# The trackable data structure containers are simple pass throughs. They
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# don't know or care about particular attributes. As a result, they will
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# consider themselves to be in a cached state, so it's up to the Layer
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# which contains them to terminate propagation.
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self.always_propagate = always_propagate
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def __repr__(self):
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return "{}\n {}".format(
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super(AttributeSentinel, self).__repr__(),
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{k: v.in_cached_state for k, v in self.attributes.items()})
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def add_parent(self, node):
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# type: (AttributeSentinel, AttributeSentinel) -> None
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# Properly tracking removal is quite challenging; however since this is only
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# used to invalidate a cache it's alright to be overly conservative. We need
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# to invalidate the cache of `node` (since it has implicitly gained a child)
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# but we don't need to invalidate self since attributes should not depend on
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# parent Layers.
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self._parents.add(node)
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node.invalidate_all()
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def get(self, key):
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# type: (AttributeSentinel, str) -> bool
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return self.attributes[key].in_cached_state
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def _set(self, key, value):
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# type: (AttributeSentinel, str, bool) -> None
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may_affect_upstream = self.attributes[key].mark_as(value)
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if may_affect_upstream or self.always_propagate:
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for node in self._parents: # type: AttributeSentinel
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node.invalidate(key)
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def mark_cached(self, key):
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# type: (AttributeSentinel, str) -> None
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self._set(key, True)
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def invalidate(self, key):
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# type: (AttributeSentinel, str) -> None
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self._set(key, False)
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def invalidate_all(self):
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# Parents may have different keys than their children, so we locally
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# invalidate but use the `invalidate_all` method of parents.
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for key in self.attributes.keys():
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self.attributes[key].mark_as(False)
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for node in self._parents:
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node.invalidate_all()
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def filter_empty_layer_containers(layer_list):
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"""Filter out empty Layer-like containers and uniquify."""
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# TODO(b/130381733): Make this an attribute in base_layer.Layer.
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existing = object_identity.ObjectIdentitySet()
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to_visit = layer_list[::-1]
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while to_visit:
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obj = to_visit.pop()
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if obj in existing:
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continue
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existing.add(obj)
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if is_layer(obj):
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yield obj
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else:
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sub_layers = getattr(obj, "layers", None) or []
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# Trackable data structures will not show up in ".layers" lists, but
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# the layers they contain will.
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to_visit.extend(sub_layers[::-1])
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