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// -*- C++ -*-
// Copyright (C) 2005-2021 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the terms
// of the GNU General Public License as published by the Free Software
// Foundation; either version 3, or (at your option) any later
// version.
// This library is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
// Permission to use, copy, modify, sell, and distribute this software
// is hereby granted without fee, provided that the above copyright
// notice appears in all copies, and that both that copyright notice
// and this permission notice appear in supporting documentation. None
// of the above authors, nor IBM Haifa Research Laboratories, make any
// representation about the suitability of this software for any
// purpose. It is provided "as is" without express or implied
// warranty.
/**
* @file timing_test_base.hpp
* Contains a base class for timing tests.
*/
#ifndef PB_DS_TIMING_TEST_BASE_HPP
#define PB_DS_TIMING_TEST_BASE_HPP
#include <performance/time/elapsed_timer.hpp>
#include <statistic/result_recorder.hpp>
namespace __gnu_pbds
{
namespace test
{
namespace detail
{
class timing_test_base
{
protected:
template<typename Functor>
double
operator()(Functor& fn);
static double
min_time_res();
private:
template<typename Functor>
std::size_t
get_min_resolution(Functor&);
template<typename Functor>
double
run_at_resolution(Functor&, std::size_t);
};
template<typename Functor>
double
timing_test_base::operator()(Functor& fn)
{
const std::size_t resolution = get_min_resolution(fn);
__gnu_pbds::test::detail::result_recorder<double> rec;
double res;
do
res = run_at_resolution(fn, resolution);
while (rec.add_result(res) == false);
res = rec.get_sample_mean() / resolution;
return res;
}
double
timing_test_base::min_time_res()
{ return 1e-7; }
template<typename Functor>
std::size_t
timing_test_base::get_min_resolution(Functor& fn)
{
std::size_t guess = 0;
const double epsilon_val = min_time_res();
double res;
do
{
guess = guess * 2 + 1;
res = run_at_resolution(fn, guess);
}
while (res < epsilon_val);
return guess;
}
template<typename Functor>
double
timing_test_base::run_at_resolution(Functor& fn, std::size_t resolution)
{
elapsed_timer res;
fn(resolution);
return res;
}
} // namespace detail
} // namespace test
} // namespace __gnu_pbds
#endif