1 | /*
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2 | ** mt19937ar.c - MT Random functions
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3 | **
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4 | ** See Copyright Notice in mruby.h
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5 | */
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6 |
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7 | #include "mruby.h"
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8 | #include "mt19937ar.h"
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9 |
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10 | /* Period parameters */
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11 | /* #define N 624 */
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12 | #define M 397
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13 | #define MATRIX_A 0x9908b0dfUL /* constant vector a */
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14 | #define UPPER_MASK 0x80000000UL /* most significant w-r bits */
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15 | #define LOWER_MASK 0x7fffffffUL /* least significant r bits */
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16 |
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17 | #if 0 /* dead_code */
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18 | static unsigned long mt[N]; /* the array for the state vector */
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19 | static int mti=N+1; /* mti==N+1 means mt[N] is not initialized */
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20 | #endif /* dead_code */
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21 |
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22 | void mrb_random_init_genrand(mt_state *t, unsigned long s)
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23 | {
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24 | t->mt[0]= s & 0xffffffffUL;
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25 | for (t->mti=1; t->mti<N; t->mti++) {
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26 | t->mt[t->mti] =
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27 | (1812433253UL * (t->mt[t->mti-1] ^ (t->mt[t->mti-1] >> 30)) + t->mti);
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28 | t->mt[t->mti] &= 0xffffffffUL;
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29 | }
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30 | }
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31 |
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32 | unsigned long mrb_random_genrand_int32(mt_state *t)
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33 | {
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34 | unsigned long y;
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35 | static const unsigned long mag01[2]={0x0UL, MATRIX_A};
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36 | /* mag01[x] = x * MATRIX_A for x=0,1 */
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37 |
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38 | if (t->mti >= N) { /* generate N words at one time */
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39 | int kk;
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40 |
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41 | if (t->mti == N+1) /* if init_genrand() has not been called, */
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42 | mrb_random_init_genrand(t, 5489UL); /* a default initial seed is used */
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43 |
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44 | for (kk=0;kk<N-M;kk++) {
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45 | y = (t->mt[kk]&UPPER_MASK)|(t->mt[kk+1]&LOWER_MASK);
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46 | t->mt[kk] = t->mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1UL];
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47 | }
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48 | for (;kk<N-1;kk++) {
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49 | y = (t->mt[kk]&UPPER_MASK)|(t->mt[kk+1]&LOWER_MASK);
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50 | t->mt[kk] = t->mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1UL];
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51 | }
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52 | y = (t->mt[N-1]&UPPER_MASK)|(t->mt[0]&LOWER_MASK);
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53 | t->mt[N-1] = t->mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1UL];
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54 |
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55 | t->mti = 0;
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56 | }
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57 |
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58 | y = t->mt[t->mti++];
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59 |
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60 | /* Tempering */
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61 | y ^= (y >> 11);
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62 | y ^= (y << 7) & 0x9d2c5680UL;
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63 | y ^= (y << 15) & 0xefc60000UL;
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64 | y ^= (y >> 18);
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65 |
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66 | t->gen.int_ = y;
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67 |
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68 | return y;
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69 | }
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70 |
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71 | double mrb_random_genrand_real1(mt_state *t)
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72 | {
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73 | mrb_random_genrand_int32(t);
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74 | t->gen.double_ = t->gen.int_*(1.0/4294967295.0);
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75 | return t->gen.double_;
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76 | /* divided by 2^32-1 */
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77 | }
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78 |
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79 | #if 0 /* dead_code */
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80 | /* initializes mt[N] with a seed */
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81 | void init_genrand(unsigned long s)
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82 | {
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83 | mt[0]= s & 0xffffffffUL;
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84 | for (mti=1; mti<N; mti++) {
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85 | mt[mti] =
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86 | (1812433253UL * (mt[mti-1] ^ (mt[mti-1] >> 30)) + mti);
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87 | /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
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88 | /* In the previous versions, MSBs of the seed affect */
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89 | /* only MSBs of the array mt[]. */
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90 | /* 2002/01/09 modified by Makoto Matsumoto */
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91 | mt[mti] &= 0xffffffffUL;
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92 | /* for >32 bit machines */
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93 | }
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94 | }
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95 |
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96 | /* initialize by an array with array-length */
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97 | /* init_key is the array for initializing keys */
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98 | /* key_length is its length */
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99 | /* slight change for C++, 2004/2/26 */
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100 | void init_by_array(unsigned long init_key[], int key_length)
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101 | {
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102 | int i, j, k;
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103 | init_genrand(19650218UL);
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104 | i=1; j=0;
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105 | k = (N>key_length ? N : key_length);
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106 | for (; k; k--) {
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107 | mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1664525UL))
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108 | + init_key[j] + j; /* non linear */
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109 | mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
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110 | i++; j++;
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111 | if (i>=N) { mt[0] = mt[N-1]; i=1; }
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112 | if (j>=key_length) j=0;
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113 | }
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114 | for (k=N-1; k; k--) {
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115 | mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1566083941UL))
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116 | - i; /* non linear */
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117 | mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
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118 | i++;
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119 | if (i>=N) { mt[0] = mt[N-1]; i=1; }
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120 | }
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121 |
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122 | mt[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array */
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123 | }
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124 |
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125 | /* generates a random number on [0,0xffffffff]-interval */
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126 | unsigned long genrand_int32(void)
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127 | {
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128 | unsigned long y;
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129 | static const unsigned long mag01[2]={0x0UL, MATRIX_A};
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130 | /* mag01[x] = x * MATRIX_A for x=0,1 */
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131 |
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132 | if (mti >= N) { /* generate N words at one time */
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133 | int kk;
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134 |
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135 | if (mti == N+1) /* if init_genrand() has not been called, */
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136 | init_genrand(5489UL); /* a default initial seed is used */
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137 |
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138 | for (kk=0;kk<N-M;kk++) {
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139 | y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
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140 | mt[kk] = mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1UL];
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141 | }
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142 | for (;kk<N-1;kk++) {
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143 | y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
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144 | mt[kk] = mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1UL];
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145 | }
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146 | y = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK);
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147 | mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1UL];
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148 |
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149 | mti = 0;
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150 | }
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151 |
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152 | y = mt[mti++];
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153 |
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154 | /* Tempering */
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155 | y ^= (y >> 11);
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156 | y ^= (y << 7) & 0x9d2c5680UL;
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157 | y ^= (y << 15) & 0xefc60000UL;
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158 | y ^= (y >> 18);
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159 |
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160 | return y;
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161 | }
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162 |
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163 | /* generates a random number on [0,0x7fffffff]-interval */
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164 | long genrand_int31(void)
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165 | {
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166 | return (long)(genrand_int32()>>1);
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167 | }
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168 |
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169 | /* generates a random number on [0,1]-real-interval */
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170 | double genrand_real1(void)
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171 | {
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172 | return genrand_int32()*(1.0/4294967295.0);
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173 | /* divided by 2^32-1 */
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174 | }
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175 |
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176 | /* generates a random number on [0,1)-real-interval */
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177 | double genrand_real2(void)
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178 | {
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179 | return genrand_int32()*(1.0/4294967296.0);
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180 | /* divided by 2^32 */
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181 | }
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182 |
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183 | /* generates a random number on (0,1)-real-interval */
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184 | double genrand_real3(void)
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185 | {
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186 | return (((double)genrand_int32()) + 0.5)*(1.0/4294967296.0);
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187 | /* divided by 2^32 */
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188 | }
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189 |
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190 | /* generates a random number on [0,1) with 53-bit resolution*/
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191 | double genrand_res53(void)
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192 | {
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193 | unsigned long a=genrand_int32()>>5, b=genrand_int32()>>6;
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194 | return(a*67108864.0+b)*(1.0/9007199254740992.0);
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195 | }
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196 | /* These real versions are due to Isaku Wada, 2002/01/09 added */
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197 | #endif /* dead_code */
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