summaryrefslogtreecommitdiffstats
path: root/tdecore/krandomsequence.cpp
blob: 8896db70b34da0a784748c60e5ea14084b305500 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
/*
  This file is part of the KDE libraries
  Copyright (c) 1999 Sean Harmer <[email protected]>

  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 "tdeapplication.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 = -((TDEApplication::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());
}