255 lines
6.9 KiB
C++
Executable File
255 lines
6.9 KiB
C++
Executable File
#ifndef RANDOM_H__
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#define RANDOM_H__
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/*
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A random generator class based on Mersenne-Twister.
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"UPDATE"
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http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/elicense.html
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---------------------------------------------------------------------
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Commercial Use of Mersenne Twister
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2001/4/6
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Until 2001/4/6, MT had been distributed under GNU Public License, but
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after 2001/4/6, we decided to let MT be used for any purpose, including
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commercial use. 2002-versions mt19937ar.c, mt19937ar-cok.c are considered
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to be usable freely.
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*/
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#include "../platform/time.h"
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#include <cmath>
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class Random
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{
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public:
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Random() {
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setSeed( getTimeMs() );
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}
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Random( long seed ) {
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setSeed( seed );
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}
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void setSeed( long seed ) {
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_seed = seed;
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_mti = N + 1;
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haveNextNextGaussian = false;
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nextNextGaussian = 0;
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init_genrand(seed);
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}
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long getSeed() {
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return _seed;
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}
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bool nextBoolean() {
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return (genrand_int32() & 0x8000000) > 0;
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}
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float nextFloat() {
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return (float)genrand_real2();
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}
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double nextDouble() {
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return genrand_real2();
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}
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int nextInt() {
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return (int)(genrand_int32()>>1);
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}
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int nextInt(int n) {
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return genrand_int32() % n;
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}
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int /* long long */ nextLong() {
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return (int)(genrand_int32()>>1);
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}
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int /* long long */ nextLong(int /*long long*/ n) {
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return genrand_int32() % n;
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}
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float nextGaussian()
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{
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if (haveNextNextGaussian) {
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haveNextNextGaussian = false;
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return nextNextGaussian;
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} else {
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float v1, v2, s;
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do {
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v1 = 2 * nextFloat() - 1; // between -1.0 and 1.0
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v2 = 2 * nextFloat() - 1; // between -1.0 and 1.0
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s = v1 * v1 + v2 * v2;
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} while (s >= 1 || s == 0);
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float multiplier = std::sqrt(-2 * std::log(s)/s);
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nextNextGaussian = v2 * multiplier;
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haveNextNextGaussian = true;
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return v1 * multiplier;
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}
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}
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private:
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long _seed;
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/* Period parameters */
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static const int N = 624;
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static const int M = 397;
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static const unsigned int MATRIX_A = 0x9908b0dfUL; /* constant vector a */
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static const unsigned int UPPER_MASK = 0x80000000UL; /* most significant w-r bits */
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static const unsigned int LOWER_MASK = 0x7fffffffUL; /* least significant r bits */
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unsigned long _mt[N]; /* the array for the state vector */
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int _mti; /* _mti==N+1 means _mt[N] is not initialized */
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bool haveNextNextGaussian;
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float nextNextGaussian;
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/* initializes _mt[N] with a seed */
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void init_genrand(unsigned long s)
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{
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_mt[0] = s & 0xffffffffUL;
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for (_mti=1; _mti < N; _mti++) {
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_mt[_mti] =
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(1812433253UL * (_mt[_mti-1] ^ (_mt[_mti-1] >> 30)) + _mti);
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/* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
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/* In the previous versions, MSBs of the seed affect */
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/* only MSBs of the array _mt[]. */
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/* 2002/01/09 modified by Makoto Matsumoto */
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_mt[_mti] &= 0xffffffffUL;
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/* for >32 bit machines */
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}
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}
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/* initialize by an array with array-length */
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/* init_key is the array for initializing keys */
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/* key_length is its length */
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/* slight change for C++, 2004/2/26 */
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void init_by_array(unsigned long init_key[], int key_length)
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{
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int i, j, k;
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init_genrand(19650218UL);
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i=1; j=0;
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k = (N>key_length ? N : key_length);
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for (; k; k--) {
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_mt[i] = (_mt[i] ^ ((_mt[i-1] ^ (_mt[i-1] >> 30)) * 1664525UL))
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+ init_key[j] + j; /* non linear */
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_mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
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i++; j++;
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if (i>=N) { _mt[0] = _mt[N-1]; i=1; }
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if (j>=key_length) j=0;
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}
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for (k=N-1; k; k--) {
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_mt[i] = (_mt[i] ^ ((_mt[i-1] ^ (_mt[i-1] >> 30)) * 1566083941UL))
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- i; /* non linear */
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_mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
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i++;
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if (i>=N) { _mt[0] = _mt[N-1]; i=1; }
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}
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_mt[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array */
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}
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/* generates a random number on [0,0xffffffff]-interval */
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unsigned long genrand_int32(void)
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{
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unsigned long y;
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static unsigned long mag01[2]={0x0UL, MATRIX_A};
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/* mag01[x] = x * MATRIX_A for x=0,1 */
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if (_mti >= N) { /* generate N words at one time */
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//static Stopwatch sw;
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//sw.start();
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int kk;
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if (_mti == N+1) /* if init_genrand() has not been called, */
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init_genrand(5489UL); /* a default initial seed is used */
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for (kk=0;kk<N-M;kk++) {
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y = (_mt[kk]&UPPER_MASK)|(_mt[kk+1]&LOWER_MASK);
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_mt[kk] = _mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1UL];
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}
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for (;kk<N-1;kk++) {
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y = (_mt[kk]&UPPER_MASK)|(_mt[kk+1]&LOWER_MASK);
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_mt[kk] = _mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1UL];
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}
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y = (_mt[N-1]&UPPER_MASK)|(_mt[0]&LOWER_MASK);
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_mt[N-1] = _mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1UL];
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_mti = 0;
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//sw.stop();
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//sw.printEvery(100, "genrand:");
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}
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y = _mt[_mti++];
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/* Tempering */
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y ^= (y >> 11);
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y ^= (y << 7) & 0x9d2c5680UL;
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y ^= (y << 15) & 0xefc60000UL;
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y ^= (y >> 18);
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return y;
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}
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/* generates a random number on [0,0x7fffffff]-interval */
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long genrand_int31(void)
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{
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return (long)(genrand_int32()>>1);
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}
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/* generates a random number on [0,1]-real-interval */
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double genrand_real1(void)
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{
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return genrand_int32()*(1.0/4294967295.0);
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/* divided by 2^32-1 */
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}
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/* generates a random number on [0,1)-real-interval */
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double genrand_real2(void)
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{
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return genrand_int32()*(1.0/4294967296.0);
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/* divided by 2^32 */
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}
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/* generates a random number on (0,1)-real-interval */
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double genrand_real3(void)
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{
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return (((double)genrand_int32()) + 0.5)*(1.0/4294967296.0);
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/* divided by 2^32 */
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}
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/* generates a random number on [0,1) with 53-bit resolution*/
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double genrand_res53(void)
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{
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unsigned long a=genrand_int32()>>5, b=genrand_int32()>>6;
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return(a*67108864.0+b)*(1.0/9007199254740992.0);
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}
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/* These real versions are due to Isaku Wada, 2002/01/09 added */
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//
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// Added helper (and quicker) functions
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//
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void rrDiff(float &x) {
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unsigned long u = genrand_int32();
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const float xx0 = ( u & 0xffff) / 65536.0f; // 2 x 16 bits
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const float xx1 = ((u >> 16) & 0xffff) / 65536.0f;
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x = xx0 - xx1;
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}
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void rrDiff(float& x, float& y) {
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unsigned long u = genrand_int32();
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const float xx0 = ((u ) & 0xff) / 256.0f; // 4 x 8 bits
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const float xx1 = ((u >> 8) & 0xff) / 256.0f;
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const float yy0 = ((u >> 16)& 0xff) / 256.0f;
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const float yy1 = ((u >> 24)& 0xff) / 256.0f;
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x = xx0 - xx1;
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y = yy0 - yy1;
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}
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void rrDiff(float& x, float& y, float& z) {
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unsigned long u = genrand_int32();
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const float xx0 = ((u ) & 0x1f) / 32.0f; // 6 x 5 bits
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const float xx1 = ((u >> 5) & 0x1f) / 32.0f;
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const float yy0 = ((u >> 10)& 0x1f) / 32.0f;
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const float yy1 = ((u >> 15)& 0x1f) / 32.0f;
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const float zz0 = ((u >> 20)& 0x1f) / 32.0f;
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const float zz1 = ((u >> 25)& 0x1f) / 32.0f;
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x = xx0 - xx1;
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y = yy0 - yy1;
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z = zz0 - zz1;
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}
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};
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#endif /*RANDOM_H__*/
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