COIN-OR::LEMON - Graph Library

Changeset 2372:7fcc0179fb21 in lemon-0.x


Ignore:
Timestamp:
02/19/07 20:55:13 (12 years ago)
Author:
Balazs Dezso
Branch:
default
Phase:
public
Convert:
svn:c9d7d8f5-90d6-0310-b91f-818b3a526b0e/lemon/trunk@3187
Message:

Adding original license to the file
+ buffered bit generation

File:
1 edited

Legend:

Unmodified
Added
Removed
  • lemon/random.h

    r2356 r2372  
    1515 * purpose.
    1616 *
     17 */
     18
     19/*
     20 * This file contains the reimplemented version of the Mersenne Twister
     21 * Generator of Matsumoto and Nishimura.
     22 *
     23 * See the appropriate copyright notice below.
     24 *
     25 * Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
     26 * All rights reserved.                         
     27 *
     28 * Redistribution and use in source and binary forms, with or without
     29 * modification, are permitted provided that the following conditions
     30 * are met:
     31 *
     32 * 1. Redistributions of source code must retain the above copyright
     33 *    notice, this list of conditions and the following disclaimer.
     34 *
     35 * 2. Redistributions in binary form must reproduce the above copyright
     36 *    notice, this list of conditions and the following disclaimer in the
     37 *    documentation and/or other materials provided with the distribution.
     38 *
     39 * 3. The names of its contributors may not be used to endorse or promote
     40 *    products derived from this software without specific prior written
     41 *    permission.
     42 *
     43 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     44 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     45 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     46 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
     47 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     48 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     49 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     50 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     51 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     52 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     53 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
     54 * OF THE POSSIBILITY OF SUCH DAMAGE.
     55 *
     56 *
     57 * Any feedback is very welcome.
     58 * http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
     59 * email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)
    1760 */
    1861
     
    398441      static bool convert(RandomCore<Word>& rnd) {
    399442        return (rnd() & 1) == 1;
     443      }
     444    };
     445
     446    template <typename Word>
     447    struct BoolProducer {
     448      Word buffer;
     449      int num;
     450     
     451      BoolProducer() : num(0) {}
     452
     453      bool convert(RandomCore<Word>& rnd) {
     454        if (num == 0) {
     455          buffer = rnd();
     456          num = RandomTraits<Word>::bits;
     457        }
     458        bool r = (buffer & 1);
     459        buffer >>= 1;
     460        --num;
     461        return r;
    400462      }
    401463    };
     
    461523   
    462524    _random_bits::RandomCore<Word> core;
     525    _random_bits::BoolProducer<Word> bool_producer;
     526   
    463527
    464528  public:
     
    620684    /// \brief Returns a random bool
    621685    ///
    622     /// It returns a random bool
     686    /// It returns a random bool. The generator holds a buffer for
     687    /// random bits. Every time when it become empty the generator makes
     688    /// a new random word and fill the buffer up.
    623689    bool boolean() {
    624       return _random_bits::BoolConversion<Word>::convert(core);
     690      return bool_producer.convert(core);
    625691    }
    626692
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