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1 /* |
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2 A C-program for MT19937, with initialization improved 2002/1/26. |
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3 Coded by Takuji Nishimura and Makoto Matsumoto. |
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4 |
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5 Before using, initialize the state by using init_genrand(seed) |
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6 or init_by_array(init_key, key_length). |
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7 |
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8 Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura, |
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9 All rights reserved. |
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10 |
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11 Redistribution and use in source and binary forms, with or without |
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12 modification, are permitted provided that the following conditions |
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13 are met: |
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14 |
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15 1. Redistributions of source code must retain the above copyright |
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16 notice, this list of conditions and the following disclaimer. |
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17 |
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18 2. Redistributions in binary form must reproduce the above copyright |
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19 notice, this list of conditions and the following disclaimer in the |
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20 documentation and/or other materials provided with the distribution. |
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21 |
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22 3. The names of its contributors may not be used to endorse or promote |
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23 products derived from this software without specific prior written |
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24 permission. |
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25 |
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26 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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27 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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28 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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29 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
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30 CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
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31 EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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32 PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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33 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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34 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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35 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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36 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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37 |
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38 |
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39 Any feedback is very welcome. |
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40 http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html |
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41 email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space) |
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42 */ |
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43 |
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44 #include <stdio.h> |
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45 |
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46 /* Period parameters */ |
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47 #define N 624 |
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48 #define M 397 |
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49 #define MATRIX_A 0x9908b0dfUL /* constant vector a */ |
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50 #define UPPER_MASK 0x80000000UL /* most significant w-r bits */ |
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51 #define LOWER_MASK 0x7fffffffUL /* least significant r bits */ |
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52 |
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53 static unsigned long mt[N]; /* the array for the state vector */ |
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54 static int mti=N+1; /* mti==N+1 means mt[N] is not initialized */ |
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55 |
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56 /* initializes mt[N] with a seed */ |
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57 void init_genrand(unsigned long s) |
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58 { |
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59 mt[0]= s & 0xffffffffUL; |
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60 for (mti=1; mti<N; mti++) { |
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61 mt[mti] = (1812433253UL * (mt[mti-1] ^ (mt[mti-1] >> 30)) + mti); |
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62 /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */ |
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63 /* In the previous versions, MSBs of the seed affect */ |
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64 /* only MSBs of the array mt[]. */ |
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65 /* 2002/01/09 modified by Makoto Matsumoto */ |
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66 mt[mti] &= 0xffffffffUL; |
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67 /* for >32 bit machines */ |
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68 } |
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69 } |
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70 |
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71 /* initialize by an array with array-length */ |
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72 /* init_key is the array for initializing keys */ |
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73 /* key_length is its length */ |
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74 /* slight change for C++, 2004/2/26 */ |
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75 void init_by_array(unsigned long init_key[],int key_length) |
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76 { |
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77 int i, j, k; |
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78 init_genrand(19650218UL); |
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79 i=1; j=0; |
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80 k = (N>key_length ? N : key_length); |
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81 for (; k; k--) { |
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82 mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1664525UL)) |
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83 + init_key[j] + j; /* non linear */ |
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84 mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */ |
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85 i++; j++; |
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86 if (i>=N) { mt[0] = mt[N-1]; i=1; } |
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87 if (j>=key_length) j=0; |
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88 } |
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89 for (k=N-1; k; k--) { |
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90 mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1566083941UL)) |
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91 - i; /* non linear */ |
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92 mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */ |
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93 i++; |
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94 if (i>=N) { mt[0] = mt[N-1]; i=1; } |
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95 } |
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96 |
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97 mt[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array */ |
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98 } |
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99 |
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100 /* generates a random number on [0,0xffffffff]-interval */ |
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101 unsigned long genrand_int32(void) |
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102 { |
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103 unsigned long y; |
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104 static unsigned long mag01[2]={0x0UL, MATRIX_A}; |
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105 /* mag01[x] = x * MATRIX_A for x=0,1 */ |
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106 |
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107 if (mti >= N) { /* generate N words at one time */ |
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108 int kk; |
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109 |
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110 if (mti == N+1) /* if init_genrand() has not been called, */ |
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111 init_genrand(5489UL); /* a default initial seed is used */ |
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112 |
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113 for (kk=0;kk<N-M;kk++) { |
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114 y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK); |
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115 mt[kk] = mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1UL]; |
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116 } |
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117 for (;kk<N-1;kk++) { |
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118 y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK); |
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119 mt[kk] = mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1UL]; |
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120 } |
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121 y = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK); |
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122 mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1UL]; |
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123 |
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124 mti = 0; |
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125 } |
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126 |
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127 y = mt[mti++]; |
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128 |
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129 /* Tempering */ |
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130 y ^= (y >> 11); |
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131 y ^= (y << 7) & 0x9d2c5680UL; |
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132 y ^= (y << 15) & 0xefc60000UL; |
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133 y ^= (y >> 18); |
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134 |
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135 return y; |
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136 } |
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137 |
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138 /* generates a random number on [0,0x7fffffff]-interval */ |
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139 long genrand_int31(void) |
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140 { |
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141 return (long)(genrand_int32()>>1); |
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142 } |
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143 |
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144 /* generates a random number on [0,1]-real-interval */ |
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145 double genrand_real1(void) |
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146 { |
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147 return genrand_int32()*(1.0/4294967295.0); |
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148 /* divided by 2^32-1 */ |
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149 } |
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150 |
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151 /* generates a random number on [0,1)-real-interval */ |
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152 double genrand_real2(void) |
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153 { |
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154 return genrand_int32()*(1.0/4294967296.0); |
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155 /* divided by 2^32 */ |
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156 } |
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157 |
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158 /* generates a random number on (0,1)-real-interval */ |
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159 double genrand_real3(void) |
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160 { |
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161 return (((double)genrand_int32()) + 0.5)*(1.0/4294967296.0); |
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162 /* divided by 2^32 */ |
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163 } |
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164 |
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165 /* generates a random number on [0,1) with 53-bit resolution*/ |
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166 double genrand_res53(void) |
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167 { |
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168 unsigned long a=genrand_int32()>>5, b=genrand_int32()>>6; |
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169 return(a*67108864.0+b)*(1.0/9007199254740992.0); |
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170 } |