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# Copyright 2015 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from six.moves import xrange # pylint: disable=redefined-builtin
from tensorflow.python.platform import test
from tensorflow.python.summary.impl import reservoir
class ReservoirTest(test.TestCase):
def testEmptyReservoir(self):
r = reservoir.Reservoir(1)
self.assertFalse(r.Keys())
def testRespectsSize(self):
r = reservoir.Reservoir(42)
self.assertEqual(r._buckets['meaning of life']._max_size, 42)
def testItemsAndKeys(self):
r = reservoir.Reservoir(42)
r.AddItem('foo', 4)
r.AddItem('bar', 9)
r.AddItem('foo', 19)
self.assertItemsEqual(r.Keys(), ['foo', 'bar'])
self.assertEqual(r.Items('foo'), [4, 19])
self.assertEqual(r.Items('bar'), [9])
def testExceptions(self):
with self.assertRaises(ValueError):
reservoir.Reservoir(-1)
with self.assertRaises(ValueError):
reservoir.Reservoir(13.3)
r = reservoir.Reservoir(12)
with self.assertRaises(KeyError):
r.Items('missing key')
def testDeterminism(self):
"""Tests that the reservoir is deterministic."""
key = 'key'
r1 = reservoir.Reservoir(10)
r2 = reservoir.Reservoir(10)
for i in xrange(100):
r1.AddItem('key', i)
r2.AddItem('key', i)
self.assertEqual(r1.Items(key), r2.Items(key))
def testBucketDeterminism(self):
"""Tests that reservoirs are deterministic at a bucket level.
This means that only the order elements are added within a bucket matters.
"""
separate_reservoir = reservoir.Reservoir(10)
interleaved_reservoir = reservoir.Reservoir(10)
for i in xrange(100):
separate_reservoir.AddItem('key1', i)
for i in xrange(100):
separate_reservoir.AddItem('key2', i)
for i in xrange(100):
interleaved_reservoir.AddItem('key1', i)
interleaved_reservoir.AddItem('key2', i)
for key in ['key1', 'key2']:
self.assertEqual(
separate_reservoir.Items(key), interleaved_reservoir.Items(key))
def testUsesSeed(self):
"""Tests that reservoirs with different seeds keep different samples."""
key = 'key'
r1 = reservoir.Reservoir(10, seed=0)
r2 = reservoir.Reservoir(10, seed=1)
for i in xrange(100):
r1.AddItem('key', i)
r2.AddItem('key', i)
self.assertNotEqual(r1.Items(key), r2.Items(key))
def testFilterItemsByKey(self):
r = reservoir.Reservoir(100, seed=0)
for i in xrange(10):
r.AddItem('key1', i)
r.AddItem('key2', i)
self.assertEqual(len(r.Items('key1')), 10)
self.assertEqual(len(r.Items('key2')), 10)
self.assertEqual(r.FilterItems(lambda x: x <= 7, 'key2'), 2)
self.assertEqual(len(r.Items('key2')), 8)
self.assertEqual(len(r.Items('key1')), 10)
self.assertEqual(r.FilterItems(lambda x: x <= 3, 'key1'), 6)
self.assertEqual(len(r.Items('key1')), 4)
self.assertEqual(len(r.Items('key2')), 8)
class ReservoirBucketTest(test.TestCase):
def testEmptyBucket(self):
b = reservoir._ReservoirBucket(1)
self.assertFalse(b.Items())
def testFillToSize(self):
b = reservoir._ReservoirBucket(100)
for i in xrange(100):
b.AddItem(i)
self.assertEqual(b.Items(), list(xrange(100)))
self.assertEqual(b._num_items_seen, 100)
def testDoesntOverfill(self):
b = reservoir._ReservoirBucket(10)
for i in xrange(1000):
b.AddItem(i)
self.assertEqual(len(b.Items()), 10)
self.assertEqual(b._num_items_seen, 1000)
def testMaintainsOrder(self):
b = reservoir._ReservoirBucket(100)
for i in xrange(10000):
b.AddItem(i)
items = b.Items()
prev = -1
for item in items:
self.assertTrue(item > prev)
prev = item
def testKeepsLatestItem(self):
b = reservoir._ReservoirBucket(5)
for i in xrange(100):
b.AddItem(i)
last = b.Items()[-1]
self.assertEqual(last, i)
def testSizeOneBucket(self):
b = reservoir._ReservoirBucket(1)
for i in xrange(20):
b.AddItem(i)
self.assertEqual(b.Items(), [i])
self.assertEqual(b._num_items_seen, 20)
def testSizeZeroBucket(self):
b = reservoir._ReservoirBucket(0)
for i in xrange(20):
b.AddItem(i)
self.assertEqual(b.Items(), list(range(i + 1)))
self.assertEqual(b._num_items_seen, 20)
def testSizeRequirement(self):
with self.assertRaises(ValueError):
reservoir._ReservoirBucket(-1)
with self.assertRaises(ValueError):
reservoir._ReservoirBucket(10.3)
def testRemovesItems(self):
b = reservoir._ReservoirBucket(100)
for i in xrange(10):
b.AddItem(i)
self.assertEqual(len(b.Items()), 10)
self.assertEqual(b._num_items_seen, 10)
self.assertEqual(b.FilterItems(lambda x: x <= 7), 2)
self.assertEqual(len(b.Items()), 8)
self.assertEqual(b._num_items_seen, 8)
def testRemovesItemsWhenItemsAreReplaced(self):
b = reservoir._ReservoirBucket(100)
for i in xrange(10000):
b.AddItem(i)
self.assertEqual(b._num_items_seen, 10000)
# Remove items
num_removed = b.FilterItems(lambda x: x <= 7)
self.assertGreater(num_removed, 92)
self.assertEqual([], [item for item in b.Items() if item > 7])
self.assertEqual(b._num_items_seen,
int(round(10000 * (1 - float(num_removed) / 100))))
def testLazyFunctionEvaluationAndAlwaysKeepLast(self):
class FakeRandom(object):
def randint(self, a, b): # pylint:disable=unused-argument
return 999
class Incrementer(object):
def __init__(self):
self.n = 0
def increment_and_double(self, x):
self.n += 1
return x * 2
# We've mocked the randomness generator, so that once it is full, the last
# item will never get durable reservoir inclusion. Since always_keep_last is
# false, the function should only get invoked 100 times while filling up
# the reservoir. This laziness property is an essential performance
# optimization.
b = reservoir._ReservoirBucket(100, FakeRandom(), always_keep_last=False)
incrementer = Incrementer()
for i in xrange(1000):
b.AddItem(i, incrementer.increment_and_double)
self.assertEqual(incrementer.n, 100)
self.assertEqual(b.Items(), [x * 2 for x in xrange(100)])
# This time, we will always keep the last item, meaning that the function
# should get invoked once for every item we add.
b = reservoir._ReservoirBucket(100, FakeRandom(), always_keep_last=True)
incrementer = Incrementer()
for i in xrange(1000):
b.AddItem(i, incrementer.increment_and_double)
self.assertEqual(incrementer.n, 1000)
self.assertEqual(b.Items(), [x * 2 for x in xrange(99)] + [999 * 2])
class ReservoirBucketStatisticalDistributionTest(test.TestCase):
def setUp(self):
self.total = 1000000
self.samples = 10000
self.n_buckets = 100
self.total_per_bucket = self.total // self.n_buckets
self.assertEqual(self.total % self.n_buckets, 0, 'total must be evenly '
'divisible by the number of buckets')
self.assertTrue(self.total > self.samples, 'need to have more items '
'than samples')
def AssertBinomialQuantity(self, measured):
p = 1.0 * self.n_buckets / self.samples
mean = p * self.samples
variance = p * (1 - p) * self.samples
error = measured - mean
# Given that the buckets were actually binomially distributed, this
# fails with probability ~2E-9
passed = error * error <= 36.0 * variance
self.assertTrue(passed, 'found a bucket with measured %d '
'too far from expected %d' % (measured, mean))
def testBucketReservoirSamplingViaStatisticalProperties(self):
# Not related to a 'ReservoirBucket', but instead number of buckets we put
# samples into for testing the shape of the distribution
b = reservoir._ReservoirBucket(_max_size=self.samples)
# add one extra item because we always keep the most recent item, which
# would skew the distribution; we can just slice it off the end instead.
for i in xrange(self.total + 1):
b.AddItem(i)
divbins = [0] * self.n_buckets
modbins = [0] * self.n_buckets
# Slice off the last item when we iterate.
for item in b.Items()[0:-1]:
divbins[item // self.total_per_bucket] += 1
modbins[item % self.n_buckets] += 1
for bucket_index in xrange(self.n_buckets):
divbin = divbins[bucket_index]
modbin = modbins[bucket_index]
self.AssertBinomialQuantity(divbin)
self.AssertBinomialQuantity(modbin)
if __name__ == '__main__':
test.main()