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Diffstat (limited to 'tdecore/krandomsequence.cpp')
| -rw-r--r-- | tdecore/krandomsequence.cpp | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/tdecore/krandomsequence.cpp b/tdecore/krandomsequence.cpp new file mode 100644 index 000000000..04240733f --- /dev/null +++ b/tdecore/krandomsequence.cpp @@ -0,0 +1,239 @@ +/* + This file is part of the KDE libraries + Copyright (c) 1999 Sean Harmer <sh@astro.keele.ac.uk> + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public + License as published by the Free Software Foundation; either + version 2 of the License, 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public License + along with this library; see the file COPYING.LIB. If not, write to + the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, + Boston, MA 02110-1301, USA. +*/ + +#include <tqptrlist.h> + +#include "krandomsequence.h" +#include "kapplication.h" + +const int KRandomSequence::m_nShuffleTableSize = 32; + +////////////////////////////////////////////////////////////////////////////// +// Construction / Destruction +////////////////////////////////////////////////////////////////////////////// + +KRandomSequence::KRandomSequence( long lngSeed1 ) +{ + // Seed the generator + setSeed( lngSeed1 ); + + + // Set the size of the shuffle table + m_ShuffleArray = new long [m_nShuffleTableSize]; +} + +KRandomSequence::~KRandomSequence() +{ + delete [] m_ShuffleArray; +} + +KRandomSequence::KRandomSequence(const KRandomSequence &a) +{ + // Set the size of the shuffle table + m_ShuffleArray = new long [m_nShuffleTableSize]; + *this = a; +} + +KRandomSequence & +KRandomSequence::operator=(const KRandomSequence &a) +{ + m_lngSeed1 = a.m_lngSeed1; + m_lngSeed2 = a.m_lngSeed2; + m_lngShufflePos = a.m_lngShufflePos; + memcpy(m_ShuffleArray, a.m_ShuffleArray, sizeof(long)*m_nShuffleTableSize); + return *this; +} + + +////////////////////////////////////////////////////////////////////////////// +// Member Functions +////////////////////////////////////////////////////////////////////////////// + +void KRandomSequence::setSeed( long lngSeed1 ) +{ + // Convert the positive seed number to a negative one so that the Draw() + // function can intialise itself the first time it is called. We just have + // to make sure that the seed used != 0 as zero perpetuates itself in a + // sequence of random numbers. + if ( lngSeed1 < 0 ) + { + m_lngSeed1 = -1; + } + else if (lngSeed1 == 0) + { + m_lngSeed1 = -((KApplication::random() & ~1)+1); + } + else + { + m_lngSeed1 = -lngSeed1; + } +} + +static const long sMod1 = 2147483563; +static const long sMod2 = 2147483399; + +void KRandomSequence::Draw() +{ + static const long sMM1 = sMod1 - 1; + static const long sA1 = 40014; + static const long sA2 = 40692; + static const long sQ1 = 53668; + static const long sQ2 = 52774; + static const long sR1 = 12211; + static const long sR2 = 3791; + static const long sDiv = 1 + sMM1 / m_nShuffleTableSize; + + // Long period (>2 * 10^18) random number generator of L'Ecuyer with + // Bayes-Durham shuffle and added safeguards. Returns a uniform random + // deviate between 0.0 and 1.0 (exclusive of the endpoint values). Call + // with a negative number to initialize; thereafter, do not alter idum + // between successive deviates in a sequence. RNMX should approximate + // the largest floating point value that is less than 1. + + int j; // Index for the shuffle table + long k; + + // Initialise + if ( m_lngSeed1 <= 0 ) + { + m_lngSeed2 = m_lngSeed1; + + // Load the shuffle table after 8 warm-ups + for ( j = m_nShuffleTableSize + 7; j >= 0; j-- ) + { + k = m_lngSeed1 / sQ1; + m_lngSeed1 = sA1 * ( m_lngSeed1 - k*sQ1) - k*sR1; + if ( m_lngSeed1 < 0 ) + { + m_lngSeed1 += sMod1; + } + + if ( j < m_nShuffleTableSize ) + { + m_ShuffleArray[j] = m_lngSeed1; + } + } + + m_lngShufflePos = m_ShuffleArray[0]; + } + + // Start here when not initializing + + // Compute m_lngSeed1 = ( lngIA1*m_lngSeed1 ) % lngIM1 without overflows + // by Schrage's method + k = m_lngSeed1 / sQ1; + m_lngSeed1 = sA1 * ( m_lngSeed1 - k*sQ1 ) - k*sR1; + if ( m_lngSeed1 < 0 ) + { + m_lngSeed1 += sMod1; + } + + // Compute m_lngSeed2 = ( lngIA2*m_lngSeed2 ) % lngIM2 without overflows + // by Schrage's method + k = m_lngSeed2 / sQ2; + m_lngSeed2 = sA2 * ( m_lngSeed2 - k*sQ2 ) - k*sR2; + if ( m_lngSeed2 < 0 ) + { + m_lngSeed2 += sMod2; + } + + j = m_lngShufflePos / sDiv; + m_lngShufflePos = m_ShuffleArray[j] - m_lngSeed2; + m_ShuffleArray[j] = m_lngSeed1; + + if ( m_lngShufflePos < 1 ) + { + m_lngShufflePos += sMM1; + } +} + +void +KRandomSequence::modulate(int i) +{ + m_lngSeed2 -= i; + if ( m_lngSeed2 < 0 ) + { + m_lngShufflePos += sMod2; + } + Draw(); + m_lngSeed1 -= i; + if ( m_lngSeed1 < 0 ) + { + m_lngSeed1 += sMod1; + } + Draw(); +} + +double +KRandomSequence::getDouble() +{ + static const double finalAmp = 1.0 / double( sMod1 ); + static const double epsilon = 1.2E-7; + static const double maxRand = 1.0 - epsilon; + double temp; + Draw(); + // Return a value that is not one of the endpoints + if ( ( temp = finalAmp * m_lngShufflePos ) > maxRand ) + { + // We don't want to return 1.0 + return maxRand; + } + else + { + return temp; + } +} + +unsigned long +KRandomSequence::getLong(unsigned long max) +{ + Draw(); + + return max ? (((unsigned long) m_lngShufflePos) % max) : 0; +} + +bool +KRandomSequence::getBool() +{ + Draw(); + + return (((unsigned long) m_lngShufflePos) & 1); +} + +class KRandomSequenceList : public TQGList +{ + friend class KRandomSequence; +public: + KRandomSequenceList() : TQGList() { } + virtual void deleteItem( TQPtrCollection::Item ) {} +}; + +void +KRandomSequence::randomize(TQGList *_list) +{ + KRandomSequenceList *list = (KRandomSequenceList *)_list; + KRandomSequenceList l; + while(list->count()) + l.append(list->takeFirst()); + + list->append(l.takeFirst()); // Start with 1 + while(l.count()) + list->insertAt(getLong(list->count()+1), l.takeFirst()); +} |