Add missing operator= and extra methods to the SamplesStatsCounter.
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}diff --git a/rtc_base/numerics/samples_stats_counter.cc b/rtc_base/numerics/samples_stats_counter.cc
index ac07734..1348cba 100644
--- a/rtc_base/numerics/samples_stats_counter.cc
+++ b/rtc_base/numerics/samples_stats_counter.cc
@@ -17,8 +17,12 @@
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 @@
min_ = value;
}
sum_ += value;
+ sum_squared_ += value * value;
}
double SamplesStatsCounter::GetPercentile(double percentile) {
diff --git a/rtc_base/numerics/samples_stats_counter.h b/rtc_base/numerics/samples_stats_counter.h
index 8849503..a982b2e 100644
--- a/rtc_base/numerics/samples_stats_counter.h
+++ b/rtc_base/numerics/samples_stats_counter.h
@@ -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 @@
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 @@
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 @@
double min_ = std::numeric_limits<double>::max();
double max_ = std::numeric_limits<double>::min();
double sum_ = 0;
+ double sum_squared_ = 0;
bool sorted_ = false;
};
diff --git a/rtc_base/numerics/samples_stats_counter_unittest.cc b/rtc_base/numerics/samples_stats_counter_unittest.cc
index 713b5f9..e6d9f67 100644
--- a/rtc_base/numerics/samples_stats_counter_unittest.cc
+++ b/rtc_base/numerics/samples_stats_counter_unittest.cc
@@ -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 @@
}
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
