1d1a6e087a
1. Split DPQuery.accumulate_record function into preprocess_record and accumulate_preprocessed_record. 2. Add merge_sample_state function. 3. Add default implementations for some functions in DPQuery, and add base class SumAggregationDPQuery that implements some more. Only get_noised_result is still abstract. 4. Enforce that all states and parameters used as inputs and outputs to DPQuery functions are nested structures of tensors by replacing numbers with constants and Nones with empty tuples. PiperOrigin-RevId: 247975791
87 lines
3 KiB
Python
87 lines
3 KiB
Python
# Copyright 2019, The TensorFlow Authors.
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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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"""Implements DPQuery interface for normalized queries.
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"""
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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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from distutils.version import LooseVersion
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import tensorflow as tf
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from privacy.dp_query import dp_query
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if LooseVersion(tf.__version__) < LooseVersion('2.0.0'):
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nest = tf.contrib.framework.nest
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else:
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nest = tf.nest
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class NormalizedQuery(dp_query.DPQuery):
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"""DPQuery for queries with a DPQuery numerator and fixed denominator."""
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def __init__(self, numerator_query, denominator):
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"""Initializer for NormalizedQuery.
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Args:
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numerator_query: A DPQuery for the numerator.
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denominator: A value for the denominator. May be None if it will be
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supplied via the set_denominator function before get_noised_result is
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called.
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"""
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self._numerator = numerator_query
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self._denominator = (
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tf.cast(denominator, tf.float32) if denominator is not None else None)
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def initial_global_state(self):
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"""See base class."""
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# NormalizedQuery has no global state beyond the numerator state.
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return self._numerator.initial_global_state()
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def derive_sample_params(self, global_state):
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"""See base class."""
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return self._numerator.derive_sample_params(global_state)
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def initial_sample_state(self, global_state, template):
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"""See base class."""
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# NormalizedQuery has no sample state beyond the numerator state.
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return self._numerator.initial_sample_state(global_state, template)
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def preprocess_record(self, params, record):
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return self._numerator.preprocess_record(params, record)
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def accumulate_preprocessed_record(
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self, sample_state, preprocessed_record):
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"""See base class."""
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return self._numerator.accumulate_preprocessed_record(
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sample_state, preprocessed_record)
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def get_noised_result(self, sample_state, global_state):
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"""See base class."""
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noised_sum, new_sum_global_state = self._numerator.get_noised_result(
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sample_state, global_state)
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def normalize(v):
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return tf.truediv(v, self._denominator)
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return nest.map_structure(normalize, noised_sum), new_sum_global_state
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def merge_sample_states(self, sample_state_1, sample_state_2):
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"""See base class."""
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return self._numerator.merge_sample_states(sample_state_1, sample_state_2)
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def set_denominator(self, denominator):
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"""Sets the denominator for the NormalizedQuery."""
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self._denominator = tf.cast(denominator, tf.float32)
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