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Add missing operator= and extra methods to the SamplesStatsCounter.

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Add missing copy and move operator= and GetVariance and
GetStandardDeviation methods to the SamplesStatsCounter.

Change-Id: I02374aac23a00fdeefda16012311cd860bb4b1b5
Bug: webrtc:10138
Reviewed-on: https://webrtc-review.googlesource.com/c/121653
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26584}
This commit is contained in:
Artem Titov 2019-02-07 12:14:35 +01:00 committed by Commit Bot
parent 710f3d3e44
commit e6f6a0cb8d
3 changed files with 48 additions and 13 deletions
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7
rtc_base/numerics/samples_stats_counter.cc
View File

@ -17,8 +17,12 @@ namespace webrtc {
SamplesStatsCounter::SamplesStatsCounter() = default;
SamplesStatsCounter::~SamplesStatsCounter() = default;
SamplesStatsCounter::SamplesStatsCounter(SamplesStatsCounter&) = default;
SamplesStatsCounter::SamplesStatsCounter(const SamplesStatsCounter&) = default;
SamplesStatsCounter& SamplesStatsCounter::operator=(
const SamplesStatsCounter&) = default;
SamplesStatsCounter::SamplesStatsCounter(SamplesStatsCounter&&) = default;
SamplesStatsCounter& SamplesStatsCounter::operator=(SamplesStatsCounter&&) =
default;
void SamplesStatsCounter::AddSample(double value) {
samples_.push_back(value);
@ -30,6 +34,7 @@ void SamplesStatsCounter::AddSample(double value) {
min_ = value;
}
sum_ += value;
sum_squared_ += value * value;
}
double SamplesStatsCounter::GetPercentile(double percentile) {

18
rtc_base/numerics/samples_stats_counter.h
View File

@ -11,6 +11,7 @@
#ifndef RTC_BASE_NUMERICS_SAMPLES_STATS_COUNTER_H_
#define RTC_BASE_NUMERICS_SAMPLES_STATS_COUNTER_H_
#include <math.h>
#include <limits>
#include <vector>
@ -22,8 +23,10 @@ class SamplesStatsCounter {
public:
SamplesStatsCounter();
~SamplesStatsCounter();
SamplesStatsCounter(SamplesStatsCounter&);
SamplesStatsCounter(const SamplesStatsCounter&);
SamplesStatsCounter& operator=(const SamplesStatsCounter&);
SamplesStatsCounter(SamplesStatsCounter&&);
SamplesStatsCounter& operator=(SamplesStatsCounter&&);
// Adds sample to the stats in amortized O(1) time.
void AddSample(double value);
@ -49,6 +52,18 @@ class SamplesStatsCounter {
RTC_DCHECK(!IsEmpty());
return sum_ / samples_.size();
}
// Returns variance in O(1) time. This function may not be called if there are
// no samples.
double GetVariance() const {
RTC_DCHECK(!IsEmpty());
return sum_squared_ / samples_.size() - GetAverage() * GetAverage();
}
// Returns standard deviation in O(1) time. This function may not be called if
// there are no samples.
double GetStandardDeviation() const {
RTC_DCHECK(!IsEmpty());
return sqrt(GetVariance());
}
// Returns percentile in O(nlogn) on first call and in O(1) after, if no
// additions were done. This function may not be called if there are no
// samples.
@ -62,6 +77,7 @@ class SamplesStatsCounter {
double min_ = std::numeric_limits<double>::max();
double max_ = std::numeric_limits<double>::min();
double sum_ = 0;
double sum_squared_ = 0;
bool sorted_ = false;
};

36
rtc_base/numerics/samples_stats_counter_unittest.cc
View File

@ -10,6 +10,7 @@
#include "rtc_base/numerics/samples_stats_counter.h"
#include <math.h>
#include <algorithm>
#include <vector>
@ -17,6 +18,7 @@
namespace webrtc {
namespace {
SamplesStatsCounter CreateStatsFilledWithIntsFrom1ToN(int n) {
std::vector<double> data;
for (int i = 1; i <= n; i++) {
@ -30,35 +32,47 @@ SamplesStatsCounter CreateStatsFilledWithIntsFrom1ToN(int n) {
}
return stats;
}
} // namespace
TEST(SamplesStatsCounter, FullSimpleTest) {
SamplesStatsCounter stats = CreateStatsFilledWithIntsFrom1ToN(100);
ASSERT_TRUE(!stats.IsEmpty());
ASSERT_DOUBLE_EQ(stats.GetMin(), 1.0);
ASSERT_DOUBLE_EQ(stats.GetMax(), 100.0);
ASSERT_DOUBLE_EQ(stats.GetAverage(), 50.5);
ASSERT_DOUBLE_EQ(stats.GetPercentile(0), 1);
EXPECT_TRUE(!stats.IsEmpty());
EXPECT_DOUBLE_EQ(stats.GetMin(), 1.0);
EXPECT_DOUBLE_EQ(stats.GetMax(), 100.0);
EXPECT_DOUBLE_EQ(stats.GetAverage(), 50.5);
for (int i = 1; i <= 100; i++) {
double p = i / 100.0;
ASSERT_GE(stats.GetPercentile(p), i);
ASSERT_LT(stats.GetPercentile(p), i + 1);
EXPECT_GE(stats.GetPercentile(p), i);
EXPECT_LT(stats.GetPercentile(p), i + 1);
}
}
TEST(SamplesStatsCounter, VarianceAndDeviation) {
SamplesStatsCounter stats;
stats.AddSample(2);
stats.AddSample(2);
stats.AddSample(-1);
stats.AddSample(5);
EXPECT_DOUBLE_EQ(stats.GetAverage(), 2.0);
EXPECT_DOUBLE_EQ(stats.GetVariance(), 4.5);
EXPECT_DOUBLE_EQ(stats.GetStandardDeviation(), sqrt(4.5));
}
TEST(SamplesStatsCounter, FractionPercentile) {
SamplesStatsCounter stats = CreateStatsFilledWithIntsFrom1ToN(5);
ASSERT_DOUBLE_EQ(stats.GetPercentile(0.5), 3);
EXPECT_DOUBLE_EQ(stats.GetPercentile(0.5), 3);
}
TEST(SamplesStatsCounter, TestBorderValues) {
SamplesStatsCounter stats = CreateStatsFilledWithIntsFrom1ToN(5);
ASSERT_GE(stats.GetPercentile(0.01), 1);
ASSERT_LT(stats.GetPercentile(0.01), 2);
ASSERT_DOUBLE_EQ(stats.GetPercentile(1.0), 5);
EXPECT_GE(stats.GetPercentile(0.01), 1);
EXPECT_LT(stats.GetPercentile(0.01), 2);
EXPECT_DOUBLE_EQ(stats.GetPercentile(1.0), 5);
}
} // namespace webrtc