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Export of internal Abseil changes

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db8dbd0e8a7b0125a4819dfc81c9bd2496849c71 by Abseil Team <absl-team@google.com>:

Create GetSkipCount() and GetStride() methods and add rounding bias correction.

PiperOrigin-RevId: 281780897
GitOrigin-RevId: db8dbd0e8a7b0125a4819dfc81c9bd2496849c71
Change-Id: I56a97288b1cb38a9357c065747f8d9bc4b187fee
This commit is contained in:
Abseil Team 2019-11-21 10:30:22 -08:00 • committed by Gennadiy Civil
parent bcaae6009c
commit 16d9fd58a5
6 changed files with 162 additions and 30 deletions
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35
absl/base/internal/exponential_biased_test.cc
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@ -113,6 +113,35 @@ double AndersonDarlingTest(const std::vector<double>& random_sample) {
return p;
}
TEST(ExponentialBiasedTest, CoinTossDemoWithGetSkipCount) {
ExponentialBiased eb;
for (int runs = 0; runs < 10; ++runs) {
for (int flips = eb.GetSkipCount(1); flips > 0; --flips) {
printf("head...");
}
printf("tail\n");
}
int heads = 0;
for (int i = 0; i < 10000000; i += 1 + eb.GetSkipCount(1)) {
++heads;
}
printf("Heads = %d (%f%%)\n", heads, 100.0 * heads / 10000000);
}
TEST(ExponentialBiasedTest, SampleDemoWithStride) {
ExponentialBiased eb;
int stride = eb.GetStride(10);
int samples = 0;
for (int i = 0; i < 10000000; ++i) {
if (--stride == 0) {
++samples;
stride = eb.GetStride(10);
}
}
printf("Samples = %d (%f%%)\n", samples, 100.0 * samples / 10000000);
}
// Testing that NextRandom generates uniform random numbers. Applies the
// Anderson-Darling test for uniformity
TEST(ExponentialBiasedTest, TestNextRandom) {
@ -153,15 +182,15 @@ TEST(ExponentialBiasedTest, TestNextRandom) {
// variable.
TEST(ExponentialBiasedTest, InitializationModes) {
ABSL_CONST_INIT static ExponentialBiased eb_static;
EXPECT_THAT(eb_static.Get(2), Ge(0));
EXPECT_THAT(eb_static.GetSkipCount(2), Ge(0));
#if ABSL_HAVE_THREAD_LOCAL
thread_local ExponentialBiased eb_thread;
EXPECT_THAT(eb_thread.Get(2), Ge(0));
EXPECT_THAT(eb_thread.GetSkipCount(2), Ge(0));
#endif
ExponentialBiased eb_stack;
EXPECT_THAT(eb_stack.Get(2), Ge(0));
EXPECT_THAT(eb_stack.GetSkipCount(2), Ge(0));
}
} // namespace base_internal