97 lines
2.8 KiB
Python
97 lines
2.8 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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"""Gradient tape utilites."""
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from __future__ import absolute_import
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from __future__ import division
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from __future__ import print_function
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import contextlib
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from tensorflow.python import pywrap_tensorflow
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class Tape(object):
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"""Represents a gradient propagation trace."""
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def __init__(self, tape):
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self._tape = tape
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def watched_variables(self):
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return pywrap_tensorflow.TFE_Py_TapeWatchedVariables(self._tape)
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def push_new_tape(persistent=False):
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"""Pushes a new tape onto the tape stack."""
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tape = pywrap_tensorflow.TFE_Py_TapeSetNew(persistent)
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return Tape(tape)
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def push_tape(tape):
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"""Pushes an existing tape onto the tape stack."""
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pywrap_tensorflow.TFE_Py_TapeSetAdd(tape._tape) # pylint: disable=protected-access
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def watch(tensor):
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"""Marks this tensor to be watched by all tapes in the stack.
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Args:
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tensor: tensor to be watched.
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"""
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pywrap_tensorflow.TFE_Py_TapeSetWatch(tensor)
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def watch_variable(variable):
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"""Marks this variable to be watched by all tapes in the stack.
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Args:
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variable: variable to be watched.
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"""
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pywrap_tensorflow.TFE_Py_TapeSetWatchVariable(variable)
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def pop_tape(tape):
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"""Pops the top tape in the stack, if any."""
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pywrap_tensorflow.TFE_Py_TapeSetRemove(tape._tape) # pylint: disable=protected-access
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@contextlib.contextmanager
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def stop_recording():
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try:
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pywrap_tensorflow.TFE_Py_TapeSetStopOnThread()
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yield
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finally:
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pywrap_tensorflow.TFE_Py_TapeSetRestartOnThread()
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def should_record(tensors):
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"""Returns true if any tape in the stack watches any of these tensors."""
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return pywrap_tensorflow.TFE_Py_TapeSetShouldRecord(tensors)
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def record_operation(op_type, output_tensors, input_tensors, backward_function):
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"""Records the operation on all tapes in the stack."""
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pywrap_tensorflow.TFE_Py_TapeSetRecordOperation(
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op_type, output_tensors, input_tensors, backward_function)
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def delete_trace(tensor_id):
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"""Deletes traces for this Tensor from all tapes in the stack."""
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pywrap_tensorflow.TFE_Py_TapeSetDeleteTrace(tensor_id)
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def could_possibly_record():
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"""Returns True if any tape is active."""
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return not pywrap_tensorflow.TFE_Py_TapeSetIsEmpty()
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