46 lines
1.6 KiB
Python
46 lines
1.6 KiB
Python
# 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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"""Various context managers."""
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import contextlib
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from tensorflow.python.framework import ops
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from tensorflow.python.ops import tensor_array_ops
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def control_dependency_on_returns(return_value):
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"""Create a TF control dependency on the return values of a function.
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If the function had no return value, a no-op context is returned.
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Args:
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return_value: The return value to set as control dependency.
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Returns:
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A context manager.
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"""
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def control_dependency_handle(t):
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if isinstance(t, tensor_array_ops.TensorArray):
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return t.flow
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return t
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if return_value is None:
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return contextlib.contextmanager(lambda: (yield))()
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# TODO(mdan): Filter to tensor objects.
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if not isinstance(return_value, (list, tuple)):
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return_value = (return_value,)
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return_value = tuple(control_dependency_handle(t) for t in return_value)
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return ops.control_dependencies(return_value)
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