1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
import tensorflow.python.platform
from tensorflow.python.platform import googletest
from tensorflow.python.summary.impl import reservoir
class ReservoirTest(googletest.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))
class ReservoirBucketTest(googletest.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(), range(100))
def testDoesntOverfill(self):
b = reservoir._ReservoirBucket(10)
for i in xrange(1000):
b.AddItem(i)
self.assertEqual(len(b.Items()), 10)
def testMaintainsOrder(self):
b = reservoir._ReservoirBucket(100)
for i in xrange(10000):
b.AddItem(i)
items = b.Items()
prev = None
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])
def testSizeZeroBucket(self):
b = reservoir._ReservoirBucket(0)
for i in xrange(20):
b.AddItem(i)
self.assertEqual(b.Items(), range(i+1))
def testSizeRequirement(self):
with self.assertRaises(ValueError):
reservoir._ReservoirBucket(-1)
with self.assertRaises(ValueError):
reservoir._ReservoirBucket(10.3)
class ReservoirBucketStatisticalDistributionTest(googletest.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__':
googletest.main()
|
