Subversion Repositories openrisc_2011-10-31

// -*- C++ -*-

// Copyright (C) 2005, 2006, 2009 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