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mt19937ar.c
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00001 //
00002 // A C-program for MT19937, with initialization improved 2002/1/26.
00003 // Coded by Takuji Nishimura and Makoto Matsumoto.
00004 //
00005 // Before using, initialize the state by using init_genrand(seed)
00006 // or init_by_array(init_key, key_length).
00007 //
00008 // Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
00009 // All rights reserved.
00010 // Copyright (C) 2005, Mutsuo Saito,
00011 // All rights reserved.
00012 //
00013 // Redistribution and use in source and binary forms, with or without
00014 // modification, are permitted provided that the following conditions
00015 // are met:
00016 //
00017 //   1. Redistributions of source code must retain the above copyright
00018 //      notice, this list of conditions and the following disclaimer.
00019 //
00020 //   2. Redistributions in binary form must reproduce the above copyright
00021 //      notice, this list of conditions and the following disclaimer in the
00022 //      documentation and/or other materials provided with the distribution.
00023 //
00024 //   3. The names of its contributors may not be used to endorse or promote
00025 //      products derived from this software without specific prior written
00026 //      permission.
00027 //
00028 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00029 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00030 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
00031 // A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
00032 // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00033 // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
00034 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
00035 // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
00036 // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
00037 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
00038 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00039 //
00040 //
00041 // Any feedback is very welcome.
00042 // http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
00043 // email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)
00044 //
00045 
00050 
00051 #include <stdio.h>
00052 #include "mt19937ar.h"
00053 
00054 // Period parameters
00055 #define N             624
00056 #define M             397
00057 #define MATRIX_A      0x9908b0dfUL // constant vector a
00058 #define UPPER_MASK    0x80000000UL // most significant w-r bits
00059 #define LOWER_MASK    0x7fffffffUL // least significant r bits
00060 
00061 static unsigned long mt[N];        // the array for the state vector
00062 static int           mti = N + 1;  // mti==N+1 means mt[N] is not initialized
00063 
00068 void init_genrand( unsigned long s )
00069 {
00070     mt[0] = s & 0xffffffffUL;
00071     for ( mti = 1; mti < N; mti++ )
00072     {
00073         mt[mti] =
00074             ( 1812433253UL * ( mt[mti - 1] ^ ( mt[mti - 1] >> 30 ) ) + (unsigned long) mti );
00075         // See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier.
00076         // In the previous versions, MSBs of the seed affect
00077         // only MSBs of the array mt[].
00078         // 2002/01/09 modified by Makoto Matsumoto
00079         mt[mti] &= 0xffffffffUL;
00080         // for >32 bit machines
00081     }
00082 }
00083 
00090 void init_by_array( unsigned long init_key[], int key_length )
00091 {
00092     int i, j, k;
00093     init_genrand( 19650218UL );
00094     i = 1; j = 0;
00095     k = ( N > key_length ? N : key_length );
00096     for (; k; k-- )
00097     {
00098         mt[i] = ( mt[i] ^ ( ( mt[i - 1] ^ ( mt[i - 1] >> 30 ) ) * 1664525UL ) )
00099                 + init_key[j] + (unsigned long) j; // non linear
00100         mt[i] &= 0xffffffffUL;                     // for WORDSIZE > 32 machines
00101         i++; j++;
00102         if ( i >= N )
00103         {
00104             mt[0] = mt[N - 1]; i = 1;
00105         }
00106         if ( j >= key_length )
00107             j = 0;
00108     }
00109     for ( k = N - 1; k; k-- )
00110     {
00111         mt[i] = ( mt[i] ^ ( ( mt[i - 1] ^ ( mt[i - 1] >> 30 ) ) * 1566083941UL ) )
00112                 - (unsigned long) i; // non linear
00113         mt[i] &= 0xffffffffUL;       // for WORDSIZE > 32 machines
00114         i++;
00115         if ( i >= N )
00116         {
00117             mt[0] = mt[N - 1]; i = 1;
00118         }
00119     }
00120 
00121     mt[0] = 0x80000000UL; // MSB is 1; assuring non-zero initial array
00122 }
00123 
00128 unsigned long genrand_int32( void )
00129 {
00130     unsigned long        y;
00131     static unsigned long mag01[2] = { 0x0UL, MATRIX_A };
00132     // mag01[x] = x * MATRIX_A  for x=0,1
00133 
00134     if ( mti >= N )   // generate N words at one time
00135     {
00136         int kk;
00137 
00138         if ( mti == N + 1 )         // if init_genrand() has not been called,
00139             init_genrand( 5489UL ); // a default initial seed is used
00140 
00141         for ( kk = 0; kk < N - M; kk++ )
00142         {
00143             y      = ( mt[kk] & UPPER_MASK ) | ( mt[kk + 1] & LOWER_MASK );
00144             mt[kk] = mt[kk + M] ^ ( y >> 1 ) ^ mag01[y & 0x1UL];
00145         }
00146         for (; kk < N - 1; kk++ )
00147         {
00148             y      = ( mt[kk] & UPPER_MASK ) | ( mt[kk + 1] & LOWER_MASK );
00149             mt[kk] = mt[kk + ( M - N )] ^ ( y >> 1 ) ^ mag01[y & 0x1UL];
00150         }
00151         y         = ( mt[N - 1] & UPPER_MASK ) | ( mt[0] & LOWER_MASK );
00152         mt[N - 1] = mt[M - 1] ^ ( y >> 1 ) ^ mag01[y & 0x1UL];
00153 
00154         mti = 0;
00155     }
00156 
00157     y = mt[mti++];
00158 
00159     // Tempering
00160     y ^= ( y >> 11 );
00161     y ^= ( y << 7 ) & 0x9d2c5680UL;
00162     y ^= ( y << 15 ) & 0xefc60000UL;
00163     y ^= ( y >> 18 );
00164 
00165     return y;
00166 }
00167 
00172 long genrand_int31( void )
00173 {
00174     return (long) ( genrand_int32() >> 1 );
00175 }
00176 
00181 double genrand_real1( void )
00182 {
00183     return (double) genrand_int32() * ( 1.0 / 4294967295.0 );
00184     // divided by 2^32-1
00185 }
00186 
00191 double genrand_real2( void )
00192 {
00193     return (double) genrand_int32() * ( 1.0 / 4294967296.0 );
00194     // divided by 2^32
00195 }
00196 
00201 double genrand_real3( void )
00202 {
00203     return ( ( (double) genrand_int32() ) + 0.5 ) * ( 1.0 / 4294967296.0 );
00204     // divided by 2^32
00205 }
00206 
00211 double genrand_res53( void )
00212 {
00213     unsigned long a = genrand_int32() >> 5, b = genrand_int32() >> 6;
00214     return ( (double) a * 67108864.0 + (double) b ) * ( 1.0 / 9007199254740992.0 );
00215 }
00216 // These real versions are due to Isaku Wada, 2002/01/09 added
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