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Diffstat (limited to 'lib/libcxx/utils/google-benchmark/src/complexity.cc')
-rw-r--r-- | lib/libcxx/utils/google-benchmark/src/complexity.cc | 228 |
1 files changed, 0 insertions, 228 deletions
diff --git a/lib/libcxx/utils/google-benchmark/src/complexity.cc b/lib/libcxx/utils/google-benchmark/src/complexity.cc deleted file mode 100644 index 6ef17660c95..00000000000 --- a/lib/libcxx/utils/google-benchmark/src/complexity.cc +++ /dev/null @@ -1,228 +0,0 @@ -// Copyright 2016 Ismael Jimenez Martinez. All rights reserved. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -// Source project : https://github.com/ismaelJimenez/cpp.leastsq -// Adapted to be used with google benchmark - -#include "benchmark/benchmark.h" - -#include <algorithm> -#include <cmath> -#include "check.h" -#include "complexity.h" - -namespace benchmark { - -// Internal function to calculate the different scalability forms -BigOFunc* FittingCurve(BigO complexity) { - static const double kLog2E = 1.44269504088896340736; - switch (complexity) { - case oN: - return [](int64_t n) -> double { return static_cast<double>(n); }; - case oNSquared: - return [](int64_t n) -> double { return std::pow(n, 2); }; - case oNCubed: - return [](int64_t n) -> double { return std::pow(n, 3); }; - case oLogN: - /* Note: can't use log2 because Android's GNU STL lacks it */ - return [](int64_t n) { return kLog2E * log(static_cast<double>(n)); }; - case oNLogN: - /* Note: can't use log2 because Android's GNU STL lacks it */ - return [](int64_t n) { return kLog2E * n * log(static_cast<double>(n)); }; - case o1: - default: - return [](int64_t) { return 1.0; }; - } -} - -// Function to return an string for the calculated complexity -std::string GetBigOString(BigO complexity) { - switch (complexity) { - case oN: - return "N"; - case oNSquared: - return "N^2"; - case oNCubed: - return "N^3"; - case oLogN: - return "lgN"; - case oNLogN: - return "NlgN"; - case o1: - return "(1)"; - default: - return "f(N)"; - } -} - -// Find the coefficient for the high-order term in the running time, by -// minimizing the sum of squares of relative error, for the fitting curve -// given by the lambda expression. -// - n : Vector containing the size of the benchmark tests. -// - time : Vector containing the times for the benchmark tests. -// - fitting_curve : lambda expression (e.g. [](int64_t n) {return n; };). - -// For a deeper explanation on the algorithm logic, please refer to -// https://en.wikipedia.org/wiki/Least_squares#Least_squares,_regression_analysis_and_statistics - -LeastSq MinimalLeastSq(const std::vector<int64_t>& n, - const std::vector<double>& time, - BigOFunc* fitting_curve) { - double sigma_gn = 0.0; - double sigma_gn_squared = 0.0; - double sigma_time = 0.0; - double sigma_time_gn = 0.0; - - // Calculate least square fitting parameter - for (size_t i = 0; i < n.size(); ++i) { - double gn_i = fitting_curve(n[i]); - sigma_gn += gn_i; - sigma_gn_squared += gn_i * gn_i; - sigma_time += time[i]; - sigma_time_gn += time[i] * gn_i; - } - - LeastSq result; - result.complexity = oLambda; - - // Calculate complexity. - result.coef = sigma_time_gn / sigma_gn_squared; - - // Calculate RMS - double rms = 0.0; - for (size_t i = 0; i < n.size(); ++i) { - double fit = result.coef * fitting_curve(n[i]); - rms += pow((time[i] - fit), 2); - } - - // Normalized RMS by the mean of the observed values - double mean = sigma_time / n.size(); - result.rms = sqrt(rms / n.size()) / mean; - - return result; -} - -// Find the coefficient for the high-order term in the running time, by -// minimizing the sum of squares of relative error. -// - n : Vector containing the size of the benchmark tests. -// - time : Vector containing the times for the benchmark tests. -// - complexity : If different than oAuto, the fitting curve will stick to -// this one. If it is oAuto, it will be calculated the best -// fitting curve. -LeastSq MinimalLeastSq(const std::vector<int64_t>& n, - const std::vector<double>& time, const BigO complexity) { - CHECK_EQ(n.size(), time.size()); - CHECK_GE(n.size(), 2); // Do not compute fitting curve is less than two - // benchmark runs are given - CHECK_NE(complexity, oNone); - - LeastSq best_fit; - - if (complexity == oAuto) { - std::vector<BigO> fit_curves = {oLogN, oN, oNLogN, oNSquared, oNCubed}; - - // Take o1 as default best fitting curve - best_fit = MinimalLeastSq(n, time, FittingCurve(o1)); - best_fit.complexity = o1; - - // Compute all possible fitting curves and stick to the best one - for (const auto& fit : fit_curves) { - LeastSq current_fit = MinimalLeastSq(n, time, FittingCurve(fit)); - if (current_fit.rms < best_fit.rms) { - best_fit = current_fit; - best_fit.complexity = fit; - } - } - } else { - best_fit = MinimalLeastSq(n, time, FittingCurve(complexity)); - best_fit.complexity = complexity; - } - - return best_fit; -} - -std::vector<BenchmarkReporter::Run> ComputeBigO( - const std::vector<BenchmarkReporter::Run>& reports) { - typedef BenchmarkReporter::Run Run; - std::vector<Run> results; - - if (reports.size() < 2) return results; - - // Accumulators. - std::vector<int64_t> n; - std::vector<double> real_time; - std::vector<double> cpu_time; - - // Populate the accumulators. - for (const Run& run : reports) { - CHECK_GT(run.complexity_n, 0) << "Did you forget to call SetComplexityN?"; - n.push_back(run.complexity_n); - real_time.push_back(run.real_accumulated_time / run.iterations); - cpu_time.push_back(run.cpu_accumulated_time / run.iterations); - } - - LeastSq result_cpu; - LeastSq result_real; - - if (reports[0].complexity == oLambda) { - result_cpu = MinimalLeastSq(n, cpu_time, reports[0].complexity_lambda); - result_real = MinimalLeastSq(n, real_time, reports[0].complexity_lambda); - } else { - result_cpu = MinimalLeastSq(n, cpu_time, reports[0].complexity); - result_real = MinimalLeastSq(n, real_time, result_cpu.complexity); - } - - std::string run_name = reports[0].benchmark_name().substr( - 0, reports[0].benchmark_name().find('/')); - - // Get the data from the accumulator to BenchmarkReporter::Run's. - Run big_o; - big_o.run_name = run_name; - big_o.run_type = BenchmarkReporter::Run::RT_Aggregate; - big_o.aggregate_name = "BigO"; - big_o.iterations = 0; - big_o.real_accumulated_time = result_real.coef; - big_o.cpu_accumulated_time = result_cpu.coef; - big_o.report_big_o = true; - big_o.complexity = result_cpu.complexity; - - // All the time results are reported after being multiplied by the - // time unit multiplier. But since RMS is a relative quantity it - // should not be multiplied at all. So, here, we _divide_ it by the - // multiplier so that when it is multiplied later the result is the - // correct one. - double multiplier = GetTimeUnitMultiplier(reports[0].time_unit); - - // Only add label to mean/stddev if it is same for all runs - Run rms; - rms.run_name = run_name; - big_o.report_label = reports[0].report_label; - rms.run_type = BenchmarkReporter::Run::RT_Aggregate; - rms.aggregate_name = "RMS"; - rms.report_label = big_o.report_label; - rms.iterations = 0; - rms.real_accumulated_time = result_real.rms / multiplier; - rms.cpu_accumulated_time = result_cpu.rms / multiplier; - rms.report_rms = true; - rms.complexity = result_cpu.complexity; - // don't forget to keep the time unit, or we won't be able to - // recover the correct value. - rms.time_unit = reports[0].time_unit; - - results.push_back(big_o); - results.push_back(rms); - return results; -} - -} // end namespace benchmark |