dolysis
/
benchmark
mirror of https://github.com/google/benchmark.git
3
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Use the sample version of standard deviation (#383) 

* remove unnecessary weights

* use sample standard deviation

* add contributor information

* remove redundant code

* initialize variable to eliminate compiler warning
This commit is contained in:
Yixuan Qiu 2017-06-05 10:32:15 -07:00 committed by Dominic Hamon
parent 93bfabc8b8
commit f3b3dd99be
4 changed files with 17 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
AUTHORS
View File

@ -32,6 +32,7 @@ Oleksandr Sochka <sasha.sochka@gmail.com>
Paul Redmond <paul.redmond@gmail.com>
Radoslav Yovchev <radoslav.tm@gmail.com>
Shuo Chen <chenshuo@chenshuo.com>
Yixuan Qiu <yixuanq@gmail.com>
Yusuke Suzuki <utatane.tea@gmail.com>
Dirac Research
Zbigniew Skowron <zbychs@gmail.com>

1
CONTRIBUTORS
View File

@ -50,6 +50,7 @@ Pierre Phaneuf <pphaneuf@google.com>
Radoslav Yovchev <radoslav.tm@gmail.com>
Ray Glover <ray.glover@uk.ibm.com>
Shuo Chen <chenshuo@chenshuo.com>
Yixuan Qiu <yixuanq@gmail.com>
Yusuke Suzuki <utatane.tea@gmail.com>
Tobias Ulvgård <tobias.ulvgard@dirac.se>
Zbigniew Skowron <zbychs@gmail.com>

10
src/complexity.cc
View File

@ -194,16 +194,16 @@ std::vector<BenchmarkReporter::Run> ComputeStats(
CHECK_EQ(run_iterations, run.iterations);
if (run.error_occurred) continue;
real_accumulated_time_stat +=
Stat1_d(run.real_accumulated_time / run.iterations, run.iterations);
Stat1_d(run.real_accumulated_time / run.iterations);
cpu_accumulated_time_stat +=
Stat1_d(run.cpu_accumulated_time / run.iterations, run.iterations);
items_per_second_stat += Stat1_d(run.items_per_second, run.iterations);
bytes_per_second_stat += Stat1_d(run.bytes_per_second, run.iterations);
Stat1_d(run.cpu_accumulated_time / run.iterations);
items_per_second_stat += Stat1_d(run.items_per_second);
bytes_per_second_stat += Stat1_d(run.bytes_per_second);
// user counters
for(auto const& cnt : run.counters) {
auto it = counter_stats.find(cnt.first);
CHECK_NE(it, counter_stats.end());
it->second.s += Stat1_d(cnt.second, run.iterations);
it->second.s += Stat1_d(cnt.second);
}
}

16
src/stat.h
View File

@ -119,18 +119,22 @@ class Stat1 {
if (numsamples_ == 0) return VType();
VType mean = sum_ * (1.0 / numsamples_);
if (stddev) {
VType avg_squares = sum_squares_ * (1.0 / numsamples_);
*stddev = Sqrt(avg_squares - Sqr(mean));
// Sample standard deviation is undefined for n = 1
if (numsamples_ == 1) {
*stddev = VType();
} else {
VType avg_squares = sum_squares_ * (1.0 / numsamples_);
*stddev = Sqrt(numsamples_ / (numsamples_ - 1.0) * (avg_squares - Sqr(mean)));
}
}
return mean;
}
// Return the standard deviation of the sample set
VType StdDev() const {
if (numsamples_ == 0) return VType();
VType mean = Mean();
VType avg_squares = sum_squares_ * (1.0 / numsamples_);
return Sqrt(avg_squares - Sqr(mean));
VType stddev = VType();
Mean(&stddev);
return stddev;
}
private: