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rand

// MersenneTwister.h

// Mersenne Twister random number generator -- a C++ class MTRand

// Based on code by Makoto Matsumoto, Takuji Nishimura, and Shawn Cokus

// Richard J. Wagner v1.0 15 May 2003 rjwagner@writeme.com

// The Mersenne Twister is an algorithm for generating random numbers. It

// was designed with consideration of the flaws in various other generators.

// The period, 2^19937-1, and the order of equidistribution, 623 dimensions,

// are far greater. The generator is also fast; it avoids multiplication and

// division, and it benefits from caches and pipelines. For more information

// see the inventors' web page at http://www.math.keio.ac.jp/~matumoto/emt.html

// Reference

// M. Matsumoto and T. Nishimura, "Mersenne Twister: A 623-Dimensionally

// Equidistributed Uniform Pseudo-Random Number Generator", ACM Transactions on

// Modeling and Computer Simulation, Vol. 8, No. 1, January 1998, pp 3-30.

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions

// are met:

// 1. Redistributions of source code must retain the above copyright

// notice, this list of conditions and the following disclaimer.

// 2. Redistributions in binary form must reproduce the above copyright

// notice, this list of conditions and the following disclaimer in the

// documentation and/or other materials provided with the distribution.

// 3. The names of its contributors may not be used to endorse or promote

// products derived from this software without specific prior written

// permission.

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR

// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// The original code included the following notice:

// When you use this, send an email to: matumoto@math.keio.ac.jp

// with an appropriate reference to your work.

// It would be nice to CC: rjwagner@writeme.com and Cokus@math.washington.edu

// when you write.

#ifndef MERSENNETWISTER_H

#define MERSENNETWISTER_H

// Not thread safe (unless auto-initialization is avoided and each thread has

// its own MTRand object)

#include"Platform/Define.h"

#include <limits.h>

#include <time.h>

#include <math.h>

class MTRand {

// Data

public:

typedef ::uint32 uint32;

enum { N = 624 }; // length of state vector

enum { SAVE = N + 1 }; // length of array for save()

protected:

enum { M = 397 }; // period parameter

uint32 state[N]; // internal state

uint32 *pNext; // next value to get from state

int left; // number of values left before reload needed

//Methods

public:

MTRand( const uint32& oneSeed ); // initialize with a simple uint32

MTRand( uint32 *const bigSeed, uint32 const seedLength = N ); // or an array

MTRand(); // auto-initialize with /dev/urandom or time() and clock()

MTRand(const MTRand&); // prevent copy constructor

MTRand& operator=(const MTRand&); // no-op operator=

// Do NOT use for CRYPTOGRAPHY without securely hashing several returned

// values together, otherwise the generator state can be learned after

// reading 624 consecutive values.

// Access to 32-bit random numbers

double rand(); // real number in [0,1]

double rand( const double& n ); // real number in [0,n]

double randExc(); // real number in [0,1)

double randExc( const double& n ); // real number in [0,n)

double randDblExc(); // real number in (0,1)

double randDblExc( const double& n ); // real number in (0,n)

uint32 randInt(); // integer in [0,2^32-1]

uint32 randInt( const uint32& n ); // integer in [0,n] for n < 2^32

double operator()() { return rand(); } // same as rand()

// Access to 53-bit random numbers (capacity of IEEE double precision)

double rand53(); // real number in [0,1)

// Access to nonuniform random number distributions

double randNorm( const double& mean = 0.0, const double& variance = 0.0 );

// Re-seeding functions with same behavior as initializers

void seed( const uint32 oneSeed );

void seed( uint32 *const bigSeed, const uint32 seedLength = N );

void seed();

// Saving and loading generator state

void save( uint32* saveArray ) const; // to array of size SAVE

void load( uint32 *const loadArray ); // from such array

/* Mangos not use streams for random values output

friend std::ostream& operator<<( std::ostream& os, const MTRand& mtrand );

friend std::istream& operator>>( std::istream& is, MTRand& mtrand );

protected:

void initialize( const uint32 oneSeed );

void reload();

uint32 hiBit( const uint32& u ) const { return u & 0x80000000UL; }

uint32 loBit( const uint32& u ) const { return u & 0x00000001UL; }

uint32 loBits( const uint32& u ) const { return u & 0x7fffffffUL; }

uint32 mixBits( const uint32& u, const uint32& v ) const

{ return hiBit(u) | loBits(v); }

uint32 twist( const uint32& m, const uint32& s0, const uint32& s1 ) const

{ return m ^ (mixBits(s0,s1)>>1) ^ uint32(-(int32)(loBit(s1) & 0x9908b0dfUL)); }

static uint32 hash( time_t t, clock_t c );

};

inline MTRand::MTRand(const MTRand&)

{ seed(); }

inline MTRand& MTRand::operator=(const MTRand&)

{ return *this; }

inline MTRand::MTRand( const uint32& oneSeed )

{ seed(oneSeed); }

inline MTRand::MTRand( uint32 *const bigSeed, const uint32 seedLength )

{ seed(bigSeed,seedLength); }

inline MTRand::MTRand()

{ seed(); }

inline double MTRand::rand()

{ return double(randInt()) * (1.0/4294967295.0); }

inline double MTRand::rand( const double& n )

{ return rand() * n; }

inline double MTRand::randExc()

{ return double(randInt()) * (1.0/4294967296.0); }

inline double MTRand::randExc( const double& n )

{ return randExc() * n; }

inline double MTRand::randDblExc()

{ return ( double(randInt()) + 0.5 ) * (1.0/4294967296.0); }

inline double MTRand::randDblExc( const double& n )

{ return randDblExc() * n; }

inline double MTRand::rand53()

{

uint32 a = randInt() >> 5, b = randInt() >> 6;

return ( a * 67108864.0 + b ) * (1.0/9007199254740992.0); // by Isaku Wada

}

inline double MTRand::randNorm( const double& mean, const double& variance )

{

// Return a real number from a normal (Gaussian) distribution with given

// mean and variance by Box-Muller method

double r = sqrt( -2.0 * log( 1.0-randDblExc()) ) * variance;

double phi = 2.0 * 3.14159265358979323846264338328 * randExc();

return mean + r * cos(phi);

}

inline MTRand::uint32 MTRand::randInt()

{

// Pull a 32-bit integer from the generator state

// Every other access function simply transforms the numbers extracted here

if( left == 0 ) reload();

--left;

s1 = *pNext++;

s1 ^= (s1 >> 11);

s1 ^= (s1 << 7) & 0x9d2c5680UL;

s1 ^= (s1 << 15) & 0xefc60000UL;

return ( s1 ^ (s1 >> 18) );

}

inline MTRand::uint32 MTRand::randInt( const uint32& n )

{

// Find which bits are used in n

// Optimized by Magnus Jonsson (magnus@smartelectronix.com)

uint32 used = n;

used |= used >> 1;

used |= used >> 2;

used |= used >> 4;

used |= used >> 8;

used |= used >> 16;

// Draw numbers until one is found in [0,n]

uint32 i;

i = randInt() & used; // toss unused bits to shorten search

while( i > n );

return i;

}

inline void MTRand::seed( const uint32 oneSeed )

{

// Seed the generator with a simple uint32

initialize(oneSeed);

reload();

}

inline void MTRand::seed( uint32 *const bigSeed, const uint32 seedLength )

{

// Seed the generator with an array of uint32's

// There are 2^19937-1 possible initial states. This function allows

// all of those to be accessed by providing at least 19937 bits (with a

// default seed length of N = 624 uint32's). Any bits above the lower 32

// in each element are discarded.

// Just call seed() if you want to get array from /dev/urandom

initialize(19650218UL);

for( ; k; --k )

{

state[i] =

state[i] ^ ( (state[i-1] ^ (state[i-1] >> 30)) * 1664525UL );

state[i] += ( bigSeed[j] & 0xffffffffUL ) + j;

state[i] &= 0xffffffffUL;

++i; ++j;

if( i >= N ) { state[0] = state[N-1]; i = 1; }

if( j >= seedLength ) j = 0;

}

for( k = N - 1; k; --k )

{

state[i] =

state[i] ^ ( (state[i-1] ^ (state[i-1] >> 30)) * 1566083941UL );

state[i] -= i;

state[i] &= 0xffffffffUL;

++i;

if( i >= N ) { state[0] = state[N-1]; i = 1; }

}

state[0] = 0x80000000UL; // MSB is 1, assuring non-zero initial array

reload();

}

inline void MTRand::seed()

{

// Seed the generator with hash of time() and clock() values

seed( hash( time(NULL), clock() ) );

}

inline void MTRand::initialize( const uint32 seed )

{

// Initialize generator state with seed

// See Knuth TAOCP Vol 2, 3rd Ed, p.106 for multiplier.

// In previous versions, most significant bits (MSBs) of the seed affect

// only MSBs of the state array. Modified 9 Jan 2002 by Makoto Matsumoto.

*s++ = seed & 0xffffffffUL;

for( ; i < N; ++i )

{

*s++ = ( 1812433253UL * ( *r ^ (*r >> 30) ) + i ) & 0xffffffffUL;

r++;

}

inline void MTRand::reload()

{

// Generate N new values in state

// Made clearer and faster by Matthew Bellew (matthew.bellew@home.com)

for( i = N - M; i--; ++p )

*p = twist( p[M], p[0], p[1] );

for( i = M; --i; ++p )

*p = twist( p[M-N], p[0], p[1] );

*p = twist( p[M-N], p[0], state[0] );

left = N, pNext = state;

}

inline MTRand::uint32 MTRand::hash( time_t t, clock_t c )

{

// Get a uint32 from t and c

// Better than uint32(x) in case x is floating point in [0,1]

// Based on code by Lawrence Kirby (fred@genesis.demon.co.uk)

static uint32 differ = 0; // guarantee time-based seeds will change

uint32 h1 = 0;

unsigned char *p = (unsigned char *) &t;

for( size_t i = 0; i < sizeof(t); ++i )

{

h1 *= UCHAR_MAX + 2U;

h1 += p[i];

}

uint32 h2 = 0;

p = (unsigned char *) &c;

for( size_t j = 0; j < sizeof(c); ++j )

{

h2 *= UCHAR_MAX + 2U;

h2 += p[j];

}

return ( h1 + differ++ ) ^ h2;

}

inline void MTRand::save( uint32* saveArray ) const

{

for( ; i--; *sa++ = *s++ ) {}

*sa = left;

}

inline void MTRand::load( uint32 *const loadArray )

{

for( ; i--; *s++ = *la++ ) {}

left = *la;

pNext = &state[N-left];

}

/* Mangos not use streams for random values output

inline std::ostream& operator<<( std::ostream& os, const MTRand& mtrand )

{

for( ; i--; os << *s++ << "\t" ) {}

return os << mtrand.left;

}

inline std::istream& operator>>( std::istream& is, MTRand& mtrand )

{

for( ; i--; is >> *s++ ) {}

is >> mtrand.left;

mtrand.pNext = &mtrand.state[mtrand.N-mtrand.left];

return is;

}

#endif // MERSENNETWISTER_H

// Change log:

// v0.1 - First release on 15 May 2000

// - Based on code by Makoto Matsumoto, Takuji Nishimura, and Shawn Cokus

// - Translated from C to C++

// - Made completely ANSI compliant

// - Designed convenient interface for initialization, seeding, and

// obtaining numbers in default or user-defined ranges

// - Added automatic seeding from /dev/urandom or time() and clock()

// - Provided functions for saving and loading generator state

// v0.2 - Fixed bug which reloaded generator one step too late

// v0.3 - Switched to clearer, faster reload() code from Matthew Bellew

// v0.4 - Removed trailing newline in saved generator format to be consistent

// with output format of built-in types

// v0.5 - Improved portability by replacing static const int's with enum's and

// clarifying return values in seed(); suggested by Eric Heimburg

// - Removed MAXINT constant; use 0xffffffffUL instead

// v0.6 - Eliminated seed overflow when uint32 is larger than 32 bits

// - Changed integer [0,n] generator to give better uniformity

// v0.7 - Fixed operator precedence ambiguity in reload()

// - Added access for real numbers in (0,1) and (0,n)

// v0.8 - Included time.h header to properly support time_t and clock_t

// v1.0 - Revised seeding to match 26 Jan 2002 update of Nishimura and Matsumoto

// - Allowed for seeding with arrays of any length

// - Added access for real numbers in [0,1) with 53-bit resolution

// - Added access for real numbers from normal (Gaussian) distributions

// - Increased overall speed by optimizing twist()

// - Doubled speed of integer [0,n] generation

// - Fixed out-of-range number generation on 64-bit machines

// - Improved portability by substituting literal constants for long enum's

// - Changed license from GNU LGPL to BSD

#include "Util.h"

#include "sockets/socket_include.h"

#include "utf8cpp/utf8.h"

#include "mersennetwister/MersenneTwister.h"

#include "zthread/ThreadLocal.h"

typedef ZThread::ThreadLocal<MTRand> MTRandTSS;

/* NOTE: Not sure if static initialization is ok for TSS objects ,

* as I see zthread uses custom implementation of the TSS

* ,and in the consturctor there is no code ,so I suppose its ok

* If its not ok ,change it to use singleton.

static MTRandTSS mtRand;

int32 irand (int32 min, int32 max)

{

return int32 (mtRand.get ().randInt (max - min)) + min;

}

uint32 urand (uint32 min, uint32 max)

{

return mtRand.get ().randInt (max - min) + min;

}

int32 rand32 ()

{

return mtRand.get ().randInt ();

}

double rand_norm(void)

{

return mtRand.get ().randExc ();

}

double rand_chance (void)

{

return mtRand.get ().randExc (100.0);

}

//util.cpp

posted on 2013-05-21 23:58 chib 閱讀(580) 評論(0) 編輯收藏引用

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