forked from 626_privacy/tensorflow_privacy
Make DPQuery classes (almost) completely functional: the only state from the initializer that is used gets pushed into the initial_global_state.
PiperOrigin-RevId: 248424593
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17fefb3895
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3908429796
6 changed files with 100 additions and 53 deletions
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@ -257,6 +257,6 @@ class QueryWithLedger(dp_query.DPQuery):
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with tf.control_dependencies([self._ledger.finalize_sample()]):
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return self._query.get_noised_result(sample_state, global_state)
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def set_denominator(self, num_microbatches, microbatch_size=1):
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self._query.set_denominator(num_microbatches)
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def set_denominator(self, global_state, num_microbatches, microbatch_size=1):
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self._ledger.set_sample_size(num_microbatches * microbatch_size)
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return self._query.set_denominator(global_state, num_microbatches)
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@ -19,6 +19,8 @@ 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 collections
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from distutils.version import LooseVersion
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import tensorflow as tf
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@ -37,6 +39,10 @@ class GaussianSumQuery(dp_query.SumAggregationDPQuery):
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Accumulates clipped vectors, then adds Gaussian noise to the sum.
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"""
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# pylint: disable=invalid-name
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_GlobalState = collections.namedtuple(
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'_GlobalState', ['l2_norm_clip', 'stddev'])
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def __init__(self, l2_norm_clip, stddev, ledger=None):
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"""Initializes the GaussianSumQuery.
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@ -46,17 +52,26 @@ class GaussianSumQuery(dp_query.SumAggregationDPQuery):
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stddev: The stddev of the noise added to the sum.
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ledger: The privacy ledger to which queries should be recorded.
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"""
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self._l2_norm_clip = tf.cast(l2_norm_clip, tf.float32)
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self._stddev = tf.cast(stddev, tf.float32)
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self._l2_norm_clip = l2_norm_clip
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self._stddev = stddev
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self._ledger = ledger
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def make_global_state(self, l2_norm_clip, stddev):
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"""Creates a global state from the given parameters."""
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return self._GlobalState(tf.cast(l2_norm_clip, tf.float32),
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tf.cast(stddev, tf.float32))
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def initial_global_state(self):
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return self.make_global_state(self._l2_norm_clip, self._stddev)
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def derive_sample_params(self, global_state):
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return self._l2_norm_clip
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return global_state.l2_norm_clip
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def initial_sample_state(self, global_state, template):
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if self._ledger:
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dependencies = [
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self._ledger.record_sum_query(self._l2_norm_clip, self._stddev)
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self._ledger.record_sum_query(
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global_state.l2_norm_clip, global_state.stddev)
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]
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else:
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dependencies = []
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@ -89,9 +104,9 @@ class GaussianSumQuery(dp_query.SumAggregationDPQuery):
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"""See base class."""
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if LooseVersion(tf.__version__) < LooseVersion('2.0.0'):
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def add_noise(v):
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return v + tf.random_normal(tf.shape(v), stddev=self._stddev)
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return v + tf.random_normal(tf.shape(v), stddev=global_state.stddev)
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else:
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random_normal = tf.random_normal_initializer(stddev=self._stddev)
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random_normal = tf.random_normal_initializer(stddev=global_state.stddev)
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def add_noise(v):
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return v + random_normal(tf.shape(v))
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@ -19,6 +19,8 @@ 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 collections
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from distutils.version import LooseVersion
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import tensorflow as tf
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@ -33,6 +35,10 @@ else:
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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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# pylint: disable=invalid-name
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_GlobalState = collections.namedtuple(
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'_GlobalState', ['numerator_state', 'denominator'])
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def __init__(self, numerator_query, denominator):
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"""Initializer for NormalizedQuery.
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@ -43,22 +49,26 @@ class NormalizedQuery(dp_query.DPQuery):
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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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self._denominator = denominator
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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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if self._denominator is not None:
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denominator = tf.cast(self._denominator, tf.float32)
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else:
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denominator = None
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return self._GlobalState(
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self._numerator.initial_global_state(), denominator)
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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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return self._numerator.derive_sample_params(global_state.numerator_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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return self._numerator.initial_sample_state(
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global_state.numerator_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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@ -72,16 +82,17 @@ class NormalizedQuery(dp_query.DPQuery):
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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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sample_state, global_state.numerator_state)
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def normalize(v):
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return tf.truediv(v, self._denominator)
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return tf.truediv(v, global_state.denominator)
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return nest.map_structure(normalize, noised_sum), new_sum_global_state
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return (nest.map_structure(normalize, noised_sum),
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self._GlobalState(new_sum_global_state, global_state.denominator))
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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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def set_denominator(self, global_state, denominator):
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"""Returns an updated global_state with the given denominator."""
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return global_state._replace(denominator=tf.cast(denominator, tf.float32))
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@ -45,7 +45,13 @@ class QuantileAdaptiveClipSumQuery(dp_query.DPQuery):
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# pylint: disable=invalid-name
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_GlobalState = collections.namedtuple(
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'_GlobalState', ['l2_norm_clip', 'sum_state', 'clipped_fraction_state'])
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'_GlobalState', [
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'l2_norm_clip',
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'noise_multiplier',
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'target_unclipped_quantile',
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'learning_rate',
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'sum_state',
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'clipped_fraction_state'])
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# pylint: disable=invalid-name
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_SampleState = collections.namedtuple(
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@ -75,8 +81,7 @@ class QuantileAdaptiveClipSumQuery(dp_query.DPQuery):
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found for which approximately 20% of updates are clipped each round.
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learning_rate: The learning rate for the clipping norm adaptation. A
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rate of r means that the clipping norm will change by a maximum of r at
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each step. This maximum is attained when |clip - target| is 1.0. Can be
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a tf.Variable for example to implement a learning rate schedule.
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each step. This maximum is attained when |clip - target| is 1.0.
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clipped_count_stddev: The stddev of the noise added to the clipped_count.
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Since the sensitivity of the clipped count is 0.5, as a rule of thumb it
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should be about 0.5 for reasonable privacy.
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@ -84,19 +89,14 @@ class QuantileAdaptiveClipSumQuery(dp_query.DPQuery):
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estimate the clipped count quantile.
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ledger: The privacy ledger to which queries should be recorded.
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"""
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self._initial_l2_norm_clip = tf.cast(initial_l2_norm_clip, tf.float32)
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self._noise_multiplier = tf.cast(noise_multiplier, tf.float32)
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self._target_unclipped_quantile = tf.cast(
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target_unclipped_quantile, tf.float32)
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self._learning_rate = tf.cast(learning_rate, tf.float32)
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self._initial_l2_norm_clip = initial_l2_norm_clip
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self._noise_multiplier = noise_multiplier
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self._target_unclipped_quantile = target_unclipped_quantile
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self._learning_rate = learning_rate
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self._l2_norm_clip = tf.Variable(self._initial_l2_norm_clip)
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self._sum_stddev = tf.Variable(
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self._initial_l2_norm_clip * self._noise_multiplier)
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# Initialize sum query's global state with None, to be set later.
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self._sum_query = gaussian_query.GaussianSumQuery(
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self._l2_norm_clip,
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self._sum_stddev,
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ledger)
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None, None, ledger)
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# self._clipped_fraction_query is a DPQuery used to estimate the fraction of
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# records that are clipped. It accumulates an indicator 0/1 of whether each
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@ -115,29 +115,40 @@ class QuantileAdaptiveClipSumQuery(dp_query.DPQuery):
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def initial_global_state(self):
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"""See base class."""
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initial_l2_norm_clip = tf.cast(self._initial_l2_norm_clip, tf.float32)
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noise_multiplier = tf.cast(self._noise_multiplier, tf.float32)
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target_unclipped_quantile = tf.cast(self._target_unclipped_quantile,
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tf.float32)
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learning_rate = tf.cast(self._learning_rate, tf.float32)
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sum_stddev = initial_l2_norm_clip * noise_multiplier
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sum_query_global_state = self._sum_query.make_global_state(
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l2_norm_clip=initial_l2_norm_clip,
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stddev=sum_stddev)
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return self._GlobalState(
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self._initial_l2_norm_clip,
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self._sum_query.initial_global_state(),
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initial_l2_norm_clip,
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noise_multiplier,
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target_unclipped_quantile,
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learning_rate,
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sum_query_global_state,
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self._clipped_fraction_query.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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gs = global_state
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# Assign values to variables that inner sum query uses.
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tf.assign(self._l2_norm_clip, gs.l2_norm_clip)
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tf.assign(self._sum_stddev, gs.l2_norm_clip * self._noise_multiplier)
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sum_params = self._sum_query.derive_sample_params(gs.sum_state)
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sum_params = self._sum_query.derive_sample_params(global_state.sum_state)
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clipped_fraction_params = self._clipped_fraction_query.derive_sample_params(
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gs.clipped_fraction_state)
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global_state.clipped_fraction_state)
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return self._SampleParams(sum_params, clipped_fraction_params)
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def initial_sample_state(self, global_state, template):
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"""See base class."""
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clipped_fraction_state = self._clipped_fraction_query.initial_sample_state(
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global_state.clipped_fraction_state, tf.constant(0.0))
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sum_state = self._sum_query.initial_sample_state(
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global_state.sum_state, template)
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clipped_fraction_state = self._clipped_fraction_query.initial_sample_state(
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global_state.clipped_fraction_state, tf.constant(0.0))
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return self._SampleState(sum_state, clipped_fraction_state)
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def preprocess_record(self, params, record):
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@ -187,6 +198,7 @@ class QuantileAdaptiveClipSumQuery(dp_query.DPQuery):
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noised_vectors, sum_state = self._sum_query.get_noised_result(
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sample_state.sum_state, gs.sum_state)
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del sum_state # Unused. To be set explicitly later.
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clipped_fraction_result, new_clipped_fraction_state = (
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self._clipped_fraction_query.get_noised_result(
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@ -202,15 +214,20 @@ class QuantileAdaptiveClipSumQuery(dp_query.DPQuery):
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# Loss function is convex, with derivative in [-1, 1], and minimized when
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# the true quantile matches the target.
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loss_grad = unclipped_quantile - self._target_unclipped_quantile
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loss_grad = unclipped_quantile - global_state.target_unclipped_quantile
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new_l2_norm_clip = gs.l2_norm_clip - self._learning_rate * loss_grad
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new_l2_norm_clip = gs.l2_norm_clip - global_state.learning_rate * loss_grad
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new_l2_norm_clip = tf.maximum(0.0, new_l2_norm_clip)
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new_global_state = self._GlobalState(
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new_l2_norm_clip,
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sum_state,
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new_clipped_fraction_state)
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new_sum_stddev = new_l2_norm_clip * global_state.noise_multiplier
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new_sum_query_global_state = self._sum_query.make_global_state(
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l2_norm_clip=new_l2_norm_clip,
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stddev=new_sum_stddev)
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new_global_state = global_state._replace(
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l2_norm_clip=new_l2_norm_clip,
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sum_state=new_sum_query_global_state,
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clipped_fraction_state=new_clipped_fraction_state)
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return noised_vectors, new_global_state
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@ -270,7 +270,7 @@ class QuantileAdaptiveClipSumQueryTest(tf.test.TestCase):
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tf.assign(selection_probability, 0.1)
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_, global_state = test_utils.run_query(query, [record1, record2])
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expected_queries = [[0.5, 0.0], [10.0, 10.0]]
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expected_queries = [[10.0, 10.0], [0.5, 0.0]]
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formatted = ledger.get_formatted_ledger_eager()
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sample_1 = formatted[0]
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self.assertAllClose(sample_1.population_size, 10.0)
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@ -288,7 +288,7 @@ class QuantileAdaptiveClipSumQueryTest(tf.test.TestCase):
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self.assertAllClose(sample_1.selection_probability, 0.1)
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self.assertAllClose(sample_1.queries, expected_queries)
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expected_queries_2 = [[0.5, 0.0], [9.0, 9.0]]
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expected_queries_2 = [[9.0, 9.0], [0.5, 0.0]]
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self.assertAllClose(sample_2.population_size, 20.0)
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self.assertAllClose(sample_2.selection_probability, 0.2)
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self.assertAllClose(sample_2.queries, expected_queries_2)
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@ -88,7 +88,9 @@ def make_optimizer_class(cls):
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vector_loss = loss()
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if self._num_microbatches is None:
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self._num_microbatches = tf.shape(vector_loss)[0]
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self._dp_average_query.set_denominator(self._num_microbatches)
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self._global_state = self._dp_average_query.set_denominator(
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self._global_state,
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self._num_microbatches)
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sample_state = self._dp_average_query.initial_sample_state(
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self._global_state, var_list)
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microbatches_losses = tf.reshape(vector_loss,
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@ -126,7 +128,9 @@ def make_optimizer_class(cls):
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# sampling from the dataset without replacement.
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if self._num_microbatches is None:
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self._num_microbatches = tf.shape(loss)[0]
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self._dp_average_query.set_denominator(self._num_microbatches)
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self._global_state = self._dp_average_query.set_denominator(
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self._global_state,
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self._num_microbatches)
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microbatches_losses = tf.reshape(loss, [self._num_microbatches, -1])
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sample_params = (
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self._dp_average_query.derive_sample_params(self._global_state))
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