SphinxBase  5prealpha
genrand.c
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37 /*
38  A C-program for MT19937, with initialization improved 2002/1/26.
39  Coded by Takuji Nishimura and Makoto Matsumoto.
40 
41  Before using, initialize the state by using init_genrand(seed)
42  or init_by_array(init_key, key_length).
43 
44  Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
45  All rights reserved.
46 
47  Redistribution and use in source and binary forms, with or without
48  modification, are permitted provided that the following conditions
49  are met:
50 
51  1. Redistributions of source code must retain the above copyright
52  notice, this list of conditions and the following disclaimer.
53 
54  2. Redistributions in binary form must reproduce the above copyright
55 ` notice, this list of conditions and the following disclaimer in the
56  documentation and/or other materials provided with the distribution.
57 
58  3. The names of its contributors may not be used to endorse or promote
59  products derived from this software without specific prior written
60  permission.
61 
62  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
63  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
64  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
65  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
66  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
67  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
68  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
69  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
70  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
71  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
72  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
73 
74 
75  Any feedback is very welcome.
76  http://www.math.keio.ac.jp/matumoto/emt.html
77  email: matumoto@math.keio.ac.jp
78 */
79 
80 #include <stdio.h>
81 
82 #include "sphinxbase/genrand.h"
83 
84 /* Period parameters */
85 #define N 624
86 #define M 397
87 #define MATRIX_A 0x9908b0dfUL /* constant vector a */
88 #define UPPER_MASK 0x80000000UL /* most significant w-r bits */
89 #define LOWER_MASK 0x7fffffffUL /* least significant r bits */
90 
91 void init_genrand(unsigned long s);
92 
93 void
94 genrand_seed(unsigned long s)
95 {
96  init_genrand(s);
97 }
98 
99 
100 static unsigned long mt[N]; /* the array for the state vector */
101 static int mti = N + 1; /* mti==N+1 means mt[N] is not initialized */
102 
103 /* initializes mt[N] with a seed */
104 void
105 init_genrand(unsigned long s)
106 {
107  mt[0] = s & 0xffffffffUL;
108  for (mti = 1; mti < N; mti++) {
109  mt[mti] =
110  (1812433253UL * (mt[mti - 1] ^ (mt[mti - 1] >> 30)) + mti);
111  /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
112  /* In the previous versions, MSBs of the seed affect */
113  /* only MSBs of the array mt[]. */
114  /* 2002/01/09 modified by Makoto Matsumoto */
115  mt[mti] &= 0xffffffffUL;
116  /* for >32 bit machines */
117  }
118 }
119 
120 /* generates a random number on [0,0xffffffff]-interval */
121 unsigned long
122 genrand_int32(void)
123 {
124  unsigned long y;
125  static unsigned long mag01[2] = { 0x0UL, MATRIX_A };
126  /* mag01[x] = x * MATRIX_A for x=0,1 */
127 
128  if (mti >= N) { /* generate N words at one time */
129  int kk;
130 
131  if (mti == N + 1) /* if init_genrand() has not been called, */
132  init_genrand(5489UL); /* a default initial seed is used */
133 
134  for (kk = 0; kk < N - M; kk++) {
135  y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
136  mt[kk] = mt[kk + M] ^ (y >> 1) ^ mag01[y & 0x1UL];
137  }
138  for (; kk < N - 1; kk++) {
139  y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
140  mt[kk] = mt[kk + (M - N)] ^ (y >> 1) ^ mag01[y & 0x1UL];
141  }
142  y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
143  mt[N - 1] = mt[M - 1] ^ (y >> 1) ^ mag01[y & 0x1UL];
144 
145  mti = 0;
146  }
147 
148  y = mt[mti++];
149 
150  /* Tempering */
151  y ^= (y >> 11);
152  y ^= (y << 7) & 0x9d2c5680UL;
153  y ^= (y << 15) & 0xefc60000UL;
154  y ^= (y >> 18);
155 
156  return y;
157 }
158 
159 /* generates a random number on [0,0x7fffffff]-interval */
160 long
162 {
163  return (long) (genrand_int32() >> 1);
164 }
165 
166 /* generates a random number on [0,1]-real-interval */
167 double
168 genrand_real1(void)
169 {
170  return genrand_int32() * (1.0 / 4294967295.0);
171  /* divided by 2^32-1 */
172 }
173 
174 /* generates a random number on [0,1)-real-interval */
175 double
176 genrand_real2(void)
177 {
178  return genrand_int32() * (1.0 / 4294967296.0);
179  /* divided by 2^32 */
180 }
181 
182 /* generates a random number on (0,1)-real-interval */
183 double
185 {
186  return (((double) genrand_int32()) + 0.5) * (1.0 / 4294967296.0);
187  /* divided by 2^32 */
188 }
189 
190 /* generates a random number on [0,1) with 53-bit resolution*/
191 double
193 {
194  unsigned long a = genrand_int32() >> 5, b = genrand_int32() >> 6;
195  return (a * 67108864.0 + b) * (1.0 / 9007199254740992.0);
196 }
197 
198 /* These real versions are due to Isaku Wada, 2002/01/09 added */
SPHINXBASE_EXPORT double genrand_res53(void)
generates a random number on [0,1) with 53-bit resolution
Definition: genrand.c:192
SPHINXBASE_EXPORT long genrand_int31(void)
generates a random number on [0,0x7fffffff]-interval
Definition: genrand.c:161
High performance prortable random generator created by Takuji Nishimura and Makoto Matsumoto...
SPHINXBASE_EXPORT double genrand_real3(void)
generates a random number on (0,1)-real-interval
Definition: genrand.c:184
SPHINXBASE_EXPORT void genrand_seed(unsigned long s)
Initialize the seed of the random generator.
Definition: genrand.c:94