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
This commit is contained in:
Galen Andrew 2019-05-15 16:06:15 -07:00 committed by A. Unique TensorFlower
parent 17fefb3895
commit 3908429796
6 changed files with 100 additions and 53 deletions

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@ -257,6 +257,6 @@ class QueryWithLedger(dp_query.DPQuery):
with tf.control_dependencies([self._ledger.finalize_sample()]):
return self._query.get_noised_result(sample_state, global_state)
def set_denominator(self, num_microbatches, microbatch_size=1):
self._query.set_denominator(num_microbatches)
def set_denominator(self, global_state, num_microbatches, microbatch_size=1):
self._ledger.set_sample_size(num_microbatches * microbatch_size)
return self._query.set_denominator(global_state, num_microbatches)

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@ -19,6 +19,8 @@ from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import collections
from distutils.version import LooseVersion
import tensorflow as tf
@ -37,6 +39,10 @@ class GaussianSumQuery(dp_query.SumAggregationDPQuery):
Accumulates clipped vectors, then adds Gaussian noise to the sum.
"""
# pylint: disable=invalid-name
_GlobalState = collections.namedtuple(
'_GlobalState', ['l2_norm_clip', 'stddev'])
def __init__(self, l2_norm_clip, stddev, ledger=None):
"""Initializes the GaussianSumQuery.
@ -46,17 +52,26 @@ class GaussianSumQuery(dp_query.SumAggregationDPQuery):
stddev: The stddev of the noise added to the sum.
ledger: The privacy ledger to which queries should be recorded.
"""
self._l2_norm_clip = tf.cast(l2_norm_clip, tf.float32)
self._stddev = tf.cast(stddev, tf.float32)
self._l2_norm_clip = l2_norm_clip
self._stddev = stddev
self._ledger = ledger
def make_global_state(self, l2_norm_clip, stddev):
"""Creates a global state from the given parameters."""
return self._GlobalState(tf.cast(l2_norm_clip, tf.float32),
tf.cast(stddev, tf.float32))
def initial_global_state(self):
return self.make_global_state(self._l2_norm_clip, self._stddev)
def derive_sample_params(self, global_state):
return self._l2_norm_clip
return global_state.l2_norm_clip
def initial_sample_state(self, global_state, template):
if self._ledger:
dependencies = [
self._ledger.record_sum_query(self._l2_norm_clip, self._stddev)
self._ledger.record_sum_query(
global_state.l2_norm_clip, global_state.stddev)
]
else:
dependencies = []
@ -89,9 +104,9 @@ class GaussianSumQuery(dp_query.SumAggregationDPQuery):
"""See base class."""
if LooseVersion(tf.__version__) < LooseVersion('2.0.0'):
def add_noise(v):
return v + tf.random_normal(tf.shape(v), stddev=self._stddev)
return v + tf.random_normal(tf.shape(v), stddev=global_state.stddev)
else:
random_normal = tf.random_normal_initializer(stddev=self._stddev)
random_normal = tf.random_normal_initializer(stddev=global_state.stddev)
def add_noise(v):
return v + random_normal(tf.shape(v))

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@ -19,6 +19,8 @@ from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import collections
from distutils.version import LooseVersion
import tensorflow as tf
@ -33,6 +35,10 @@ else:
class NormalizedQuery(dp_query.DPQuery):
"""DPQuery for queries with a DPQuery numerator and fixed denominator."""
# pylint: disable=invalid-name
_GlobalState = collections.namedtuple(
'_GlobalState', ['numerator_state', 'denominator'])
def __init__(self, numerator_query, denominator):
"""Initializer for NormalizedQuery.
@ -43,22 +49,26 @@ class NormalizedQuery(dp_query.DPQuery):
called.
"""
self._numerator = numerator_query
self._denominator = (
tf.cast(denominator, tf.float32) if denominator is not None else None)
self._denominator = denominator
def initial_global_state(self):
"""See base class."""
# NormalizedQuery has no global state beyond the numerator state.
return self._numerator.initial_global_state()
if self._denominator is not None:
denominator = tf.cast(self._denominator, tf.float32)
else:
denominator = None
return self._GlobalState(
self._numerator.initial_global_state(), denominator)
def derive_sample_params(self, global_state):
"""See base class."""
return self._numerator.derive_sample_params(global_state)
return self._numerator.derive_sample_params(global_state.numerator_state)
def initial_sample_state(self, global_state, template):
"""See base class."""
# NormalizedQuery has no sample state beyond the numerator state.
return self._numerator.initial_sample_state(global_state, template)
return self._numerator.initial_sample_state(
global_state.numerator_state, template)
def preprocess_record(self, params, record):
return self._numerator.preprocess_record(params, record)
@ -72,16 +82,17 @@ class NormalizedQuery(dp_query.DPQuery):
def get_noised_result(self, sample_state, global_state):
"""See base class."""
noised_sum, new_sum_global_state = self._numerator.get_noised_result(
sample_state, global_state)
sample_state, global_state.numerator_state)
def normalize(v):
return tf.truediv(v, self._denominator)
return tf.truediv(v, global_state.denominator)
return nest.map_structure(normalize, noised_sum), new_sum_global_state
return (nest.map_structure(normalize, noised_sum),
self._GlobalState(new_sum_global_state, global_state.denominator))
def merge_sample_states(self, sample_state_1, sample_state_2):
"""See base class."""
return self._numerator.merge_sample_states(sample_state_1, sample_state_2)
def set_denominator(self, denominator):
"""Sets the denominator for the NormalizedQuery."""
self._denominator = tf.cast(denominator, tf.float32)
def set_denominator(self, global_state, denominator):
"""Returns an updated global_state with the given denominator."""
return global_state._replace(denominator=tf.cast(denominator, tf.float32))

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@ -45,7 +45,13 @@ class QuantileAdaptiveClipSumQuery(dp_query.DPQuery):
# pylint: disable=invalid-name
_GlobalState = collections.namedtuple(
'_GlobalState', ['l2_norm_clip', 'sum_state', 'clipped_fraction_state'])
'_GlobalState', [
'l2_norm_clip',
'noise_multiplier',
'target_unclipped_quantile',
'learning_rate',
'sum_state',
'clipped_fraction_state'])
# pylint: disable=invalid-name
_SampleState = collections.namedtuple(
@ -75,8 +81,7 @@ class QuantileAdaptiveClipSumQuery(dp_query.DPQuery):
found for which approximately 20% of updates are clipped each round.
learning_rate: The learning rate for the clipping norm adaptation. A
rate of r means that the clipping norm will change by a maximum of r at
each step. This maximum is attained when |clip - target| is 1.0. Can be
a tf.Variable for example to implement a learning rate schedule.
each step. This maximum is attained when |clip - target| is 1.0.
clipped_count_stddev: The stddev of the noise added to the clipped_count.
Since the sensitivity of the clipped count is 0.5, as a rule of thumb it
should be about 0.5 for reasonable privacy.
@ -84,19 +89,14 @@ class QuantileAdaptiveClipSumQuery(dp_query.DPQuery):
estimate the clipped count quantile.
ledger: The privacy ledger to which queries should be recorded.
"""
self._initial_l2_norm_clip = tf.cast(initial_l2_norm_clip, tf.float32)
self._noise_multiplier = tf.cast(noise_multiplier, tf.float32)
self._target_unclipped_quantile = tf.cast(
target_unclipped_quantile, tf.float32)
self._learning_rate = tf.cast(learning_rate, tf.float32)
self._initial_l2_norm_clip = initial_l2_norm_clip
self._noise_multiplier = noise_multiplier
self._target_unclipped_quantile = target_unclipped_quantile
self._learning_rate = learning_rate
self._l2_norm_clip = tf.Variable(self._initial_l2_norm_clip)
self._sum_stddev = tf.Variable(
self._initial_l2_norm_clip * self._noise_multiplier)
# Initialize sum query's global state with None, to be set later.
self._sum_query = gaussian_query.GaussianSumQuery(
self._l2_norm_clip,
self._sum_stddev,
ledger)
None, None, ledger)
# self._clipped_fraction_query is a DPQuery used to estimate the fraction of
# records that are clipped. It accumulates an indicator 0/1 of whether each
@ -115,29 +115,40 @@ class QuantileAdaptiveClipSumQuery(dp_query.DPQuery):
def initial_global_state(self):
"""See base class."""
initial_l2_norm_clip = tf.cast(self._initial_l2_norm_clip, tf.float32)
noise_multiplier = tf.cast(self._noise_multiplier, tf.float32)
target_unclipped_quantile = tf.cast(self._target_unclipped_quantile,
tf.float32)
learning_rate = tf.cast(self._learning_rate, tf.float32)
sum_stddev = initial_l2_norm_clip * noise_multiplier
sum_query_global_state = self._sum_query.make_global_state(
l2_norm_clip=initial_l2_norm_clip,
stddev=sum_stddev)
return self._GlobalState(
self._initial_l2_norm_clip,
self._sum_query.initial_global_state(),
initial_l2_norm_clip,
noise_multiplier,
target_unclipped_quantile,
learning_rate,
sum_query_global_state,
self._clipped_fraction_query.initial_global_state())
def derive_sample_params(self, global_state):
"""See base class."""
gs = global_state
# Assign values to variables that inner sum query uses.
tf.assign(self._l2_norm_clip, gs.l2_norm_clip)
tf.assign(self._sum_stddev, gs.l2_norm_clip * self._noise_multiplier)
sum_params = self._sum_query.derive_sample_params(gs.sum_state)
sum_params = self._sum_query.derive_sample_params(global_state.sum_state)
clipped_fraction_params = self._clipped_fraction_query.derive_sample_params(
gs.clipped_fraction_state)
global_state.clipped_fraction_state)
return self._SampleParams(sum_params, clipped_fraction_params)
def initial_sample_state(self, global_state, template):
"""See base class."""
clipped_fraction_state = self._clipped_fraction_query.initial_sample_state(
global_state.clipped_fraction_state, tf.constant(0.0))
sum_state = self._sum_query.initial_sample_state(
global_state.sum_state, template)
clipped_fraction_state = self._clipped_fraction_query.initial_sample_state(
global_state.clipped_fraction_state, tf.constant(0.0))
return self._SampleState(sum_state, clipped_fraction_state)
def preprocess_record(self, params, record):
@ -187,6 +198,7 @@ class QuantileAdaptiveClipSumQuery(dp_query.DPQuery):
noised_vectors, sum_state = self._sum_query.get_noised_result(
sample_state.sum_state, gs.sum_state)
del sum_state # Unused. To be set explicitly later.
clipped_fraction_result, new_clipped_fraction_state = (
self._clipped_fraction_query.get_noised_result(
@ -202,15 +214,20 @@ class QuantileAdaptiveClipSumQuery(dp_query.DPQuery):
# Loss function is convex, with derivative in [-1, 1], and minimized when
# the true quantile matches the target.
loss_grad = unclipped_quantile - self._target_unclipped_quantile
loss_grad = unclipped_quantile - global_state.target_unclipped_quantile
new_l2_norm_clip = gs.l2_norm_clip - self._learning_rate * loss_grad
new_l2_norm_clip = gs.l2_norm_clip - global_state.learning_rate * loss_grad
new_l2_norm_clip = tf.maximum(0.0, new_l2_norm_clip)
new_global_state = self._GlobalState(
new_l2_norm_clip,
sum_state,
new_clipped_fraction_state)
new_sum_stddev = new_l2_norm_clip * global_state.noise_multiplier
new_sum_query_global_state = self._sum_query.make_global_state(
l2_norm_clip=new_l2_norm_clip,
stddev=new_sum_stddev)
new_global_state = global_state._replace(
l2_norm_clip=new_l2_norm_clip,
sum_state=new_sum_query_global_state,
clipped_fraction_state=new_clipped_fraction_state)
return noised_vectors, new_global_state

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@ -270,7 +270,7 @@ class QuantileAdaptiveClipSumQueryTest(tf.test.TestCase):
tf.assign(selection_probability, 0.1)
_, global_state = test_utils.run_query(query, [record1, record2])
expected_queries = [[0.5, 0.0], [10.0, 10.0]]
expected_queries = [[10.0, 10.0], [0.5, 0.0]]
formatted = ledger.get_formatted_ledger_eager()
sample_1 = formatted[0]
self.assertAllClose(sample_1.population_size, 10.0)
@ -288,7 +288,7 @@ class QuantileAdaptiveClipSumQueryTest(tf.test.TestCase):
self.assertAllClose(sample_1.selection_probability, 0.1)
self.assertAllClose(sample_1.queries, expected_queries)
expected_queries_2 = [[0.5, 0.0], [9.0, 9.0]]
expected_queries_2 = [[9.0, 9.0], [0.5, 0.0]]
self.assertAllClose(sample_2.population_size, 20.0)
self.assertAllClose(sample_2.selection_probability, 0.2)
self.assertAllClose(sample_2.queries, expected_queries_2)

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@ -88,7 +88,9 @@ def make_optimizer_class(cls):
vector_loss = loss()
if self._num_microbatches is None:
self._num_microbatches = tf.shape(vector_loss)[0]
self._dp_average_query.set_denominator(self._num_microbatches)
self._global_state = self._dp_average_query.set_denominator(
self._global_state,
self._num_microbatches)
sample_state = self._dp_average_query.initial_sample_state(
self._global_state, var_list)
microbatches_losses = tf.reshape(vector_loss,
@ -126,7 +128,9 @@ def make_optimizer_class(cls):
# sampling from the dataset without replacement.
if self._num_microbatches is None:
self._num_microbatches = tf.shape(loss)[0]
self._dp_average_query.set_denominator(self._num_microbatches)
self._global_state = self._dp_average_query.set_denominator(
self._global_state,
self._num_microbatches)
microbatches_losses = tf.reshape(loss, [self._num_microbatches, -1])
sample_params = (
self._dp_average_query.derive_sample_params(self._global_state))