98 lines
2.8 KiB
C++
98 lines
2.8 KiB
C++
// -*- C++ -*-
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// Copyright (C) 2005-2015 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the terms
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// of the GNU General Public License as published by the Free Software
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// Foundation; either version 3, or (at your option) any later
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// version.
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// This library is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING3. If not see
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// <http://www.gnu.org/licenses/>.
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// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
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// Permission to use, copy, modify, sell, and distribute this software
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// is hereby granted without fee, provided that the above copyright
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// notice appears in all copies, and that both that copyright notice
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// and this permission notice appear in supporting documentation. None
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// of the above authors, nor IBM Haifa Research Laboratories, make any
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// representation about the suitability of this software for any
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// purpose. It is provided "as is" without express or implied
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// warranty.
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/**
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* @file testsuite_rng.h
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*/
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#ifndef _GLIBCXX_TESTSUITE_RNG_H
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#define _GLIBCXX_TESTSUITE_RNG_H
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#include <ctime>
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#include <climits>
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#include <debug/debug.h>
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#include <tr1/random>
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namespace __gnu_pbds
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{
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namespace test
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{
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class twister_rand_gen
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{
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public:
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twister_rand_gen(unsigned int seed =
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static_cast<unsigned int>(std::time(0)))
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: m_base_generator(seed)
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{
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// Do nothing.
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}
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void
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init(unsigned int seed)
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{ m_base_generator.seed(seed); }
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static unsigned int
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get_time_determined_seed()
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{ return(static_cast<unsigned int>(std::time(0))); }
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unsigned long
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get_unsigned_long(unsigned long min = 0,
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unsigned long max = UINT_MAX - 1)
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{
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_GLIBCXX_DEBUG_ASSERT(max >= min);
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const double prob = get_prob();
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const unsigned long r = (unsigned long)((max - min + 1) * prob) + min;
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_GLIBCXX_DEBUG_ASSERT(r <= max);
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return r;
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}
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double
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get_prob()
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{
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const double min = m_base_generator.min();
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const double max = m_base_generator.max();
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const double range = static_cast<const double>(max - min);
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const double res = static_cast<const double>(m_base_generator() - min);
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const double ret = res / range;
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_GLIBCXX_DEBUG_ASSERT(ret >= 0 && ret <= 1);
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return ret;
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}
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private:
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typedef std::tr1::mt19937 base_generator_t;
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base_generator_t m_base_generator;
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};
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} // namespace test
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} // namespace __gnu_pbds
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#endif // #ifndef _GLIBCXX_TESTSUITE_RNG_H
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