manolas
/
vcglib
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

added a few const, and a default value for the generate(int) call

This commit is contained in:
Paolo Cignoni 2008-12-18 00:29:03 +00:00
parent c2c940338e
commit 0b15c9b4b4
1 changed files with 335 additions and 335 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

670
vcg/math/random_generator.h
View File

@ -1,335 +1,335 @@
/**************************************************************************** /****************************************************************************
* VCGLib o o * * VCGLib o o *
* Visual and Computer Graphics Library o o * * Visual and Computer Graphics Library o o *
* _ O _ * * _ O _ *
* Copyright(C) 2004 \/)\/ * * Copyright(C) 2004 \/)\/ *
* Visual Computing Lab /\/| * * Visual Computing Lab /\/| *
* ISTI - Italian National Research Council | * * ISTI - Italian National Research Council | *
* \ * * \ *
* All rights reserved. * * All rights reserved. *
* * * *
* This program is free software; you can redistribute it and/or modify * * This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by * * it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or * * the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. * * (at your option) any later version. *
* * * *
* This program is distributed in the hope that it will be useful, * * This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of * * but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License (http://www.gnu.org/licenses/gpl.txt) * * GNU General Public License (http://www.gnu.org/licenses/gpl.txt) *
* for more details. * * for more details. *
* * * *
****************************************************************************/ ****************************************************************************/
#ifndef __VCG_RandomGenerator #ifndef __VCG_RandomGenerator
#define __VCG_RandomGenerator #define __VCG_RandomGenerator
namespace vcg { namespace vcg {
namespace math { namespace math {
/** /**
* Common interface for random generation (with uniform distribution). * Common interface for random generation (with uniform distribution).
* *
* Two RNGs are available: Subtractive Ring and an improved Marsenne-Twister. * Two RNGs are available: Subtractive Ring and an improved Marsenne-Twister.
*/ */
class RandomGenerator class RandomGenerator
{ {
// construction // construction
public: public:
RandomGenerator(){} RandomGenerator(){}
// public methods // public methods
public: public:
/// (Re-)initialize with a given seed. /// (Re-)initialize with a given seed.
virtual void initialize(unsigned int seed)=0; virtual void initialize(unsigned int seed)=0;
/// Return a random number in the given range (note that not all the RNG can handle a given limit). /// Return a random number in the given range (note that not all the RNG can handle a given limit).
virtual unsigned int generate(unsigned int limit)=0; virtual unsigned int generate(unsigned int limit)=0;
/// Return a random number in the [0,1) real interval. /// Return a random number in the [0,1) real interval.
virtual double generate01()=0; virtual double generate01()=0;
}; };
/** /**
* Uniform RNG derived from a STL extension of sgi. * Uniform RNG derived from a STL extension of sgi.
* *
* It is based on the Subtractive Ring method. * It is based on the Subtractive Ring method.
* This implementation assumes that int is 32 bits. * This implementation assumes that int is 32 bits.
* *
* References * References
* *
* D. E. Knuth, The Art of Computer Programming. Volume 2: Seminumerical Algorithms, 2nd Edition. Addison-Wesley, 1981. * D. E. Knuth, The Art of Computer Programming. Volume 2: Seminumerical Algorithms, 2nd Edition. Addison-Wesley, 1981.
* (section 3.6 of Knuth for an implementation of the subtractive method in FORTRAN) * (section 3.6 of Knuth for an implementation of the subtractive method in FORTRAN)
* (section 3.2.2 of Knuth analyzes this class of algorithms) * (section 3.2.2 of Knuth analyzes this class of algorithms)
*/ */
class SubtractiveRingRNG : public RandomGenerator class SubtractiveRingRNG : public RandomGenerator
{ {
// private data member // private data member
private: private:
// Subtractive Ring RNG status variables // Subtractive Ring RNG status variables
unsigned int _M_table[55]; unsigned int _M_table[55];
size_t _M_index1; size_t _M_index1;
size_t _M_index2; size_t _M_index2;
// construction // construction
public: public:
// ctor // ctor
SubtractiveRingRNG(int default_seed=161803398u) SubtractiveRingRNG(int default_seed=161803398u)
{ {
initialize(default_seed); initialize(default_seed);
} }
// public methods // public methods
public: public:
/// (Re-)initialize with a given seed. /// (Re-)initialize with a given seed.
void initialize(unsigned int seed) void initialize(unsigned int seed)
{ {
unsigned int __k = 1; unsigned int __k = 1;
_M_table[54] = seed; _M_table[54] = seed;
size_t __i; size_t __i;
for (__i = 0; __i < 54; __i++) for (__i = 0; __i < 54; __i++)
{ {
size_t __ii = (21 * (__i + 1) % 55) - 1; size_t __ii = (21 * (__i + 1) % 55) - 1;
_M_table[__ii] = __k; _M_table[__ii] = __k;
__k = seed - __k; __k = seed - __k;
seed = _M_table[__ii]; seed = _M_table[__ii];
} }
for (int __loop = 0; __loop < 4; __loop++) for (int __loop = 0; __loop < 4; __loop++)
{ {
for (__i = 0; __i < 55; __i++) for (__i = 0; __i < 55; __i++)
_M_table[__i] = _M_table[__i] - _M_table[(1 + __i + 30) % 55]; _M_table[__i] = _M_table[__i] - _M_table[(1 + __i + 30) % 55];
} }
_M_index1 = 0; _M_index1 = 0;
_M_index2 = 31; _M_index2 = 31;
} }
/// Return a random number in the given range (limit) using the Subtractive Ring method. /// Return a random number in the given range (limit) using the Subtractive Ring method.
unsigned int generate(unsigned int limit) unsigned int generate(unsigned int limit= 0xffffffffu)
{ {
_M_index1 = (_M_index1 + 1) % 55; _M_index1 = (_M_index1 + 1) % 55;
_M_index2 = (_M_index2 + 1) % 55; _M_index2 = (_M_index2 + 1) % 55;
_M_table[_M_index1] = _M_table[_M_index1] - _M_table[_M_index2]; _M_table[_M_index1] = _M_table[_M_index1] - _M_table[_M_index2];
return _M_table[_M_index1] % limit; return _M_table[_M_index1] % limit;
} }
/// Return a random number in the [0,1) real interval using the Subtractive Ring method. /// Return a random number in the [0,1) real interval using the Subtractive Ring method.
double generate01() double generate01()
{ {
unsigned int lmt = 0xffffffffu; const unsigned int lmt = 0xffffffffu;
unsigned int number = generate(lmt); unsigned int number = generate(lmt);
return static_cast<double>(number) / static_cast<double>(lmt); return static_cast<double>(number) / static_cast<double>(lmt);
} }
}; };
/** /**
* The second one is an improved Marsenne-Twister algorithm (MT19937) * The second one is an improved Marsenne-Twister algorithm (MT19937)
* Coded by Takuji Nishimura and Makoto Matsumoto (see copyright note below) * Coded by Takuji Nishimura and Makoto Matsumoto (see copyright note below)
* and successively modified to be a C++ class by Daniel Dunbar. * and successively modified to be a C++ class by Daniel Dunbar.
* *
* *
* References for improved Marsenne-Twister: * References for improved Marsenne-Twister:
* *
* http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html * http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
* *
*/ */
class MarsenneTwisterRNG : public RandomGenerator class MarsenneTwisterRNG : public RandomGenerator
{ {
// definitions // definitions
private: private:
static const int N = 624; static const int N = 624;
static const int M = 397; static const int M = 397;
static const unsigned int MATRIX_A = 0x9908b0dfu; // constant vector a static const unsigned int MATRIX_A = 0x9908b0dfu; // constant vector a
static const unsigned int UPPER_MASK = 0x80000000u; // most significant w-r bits static const unsigned int UPPER_MASK = 0x80000000u; // most significant w-r bits
static const unsigned int LOWER_MASK = 0x7fffffffu; // least significant r bits static const unsigned int LOWER_MASK = 0x7fffffffu; // least significant r bits
// private data member // private data member
private: private:
// Improved Marsenne-Twister RNG status variables // Improved Marsenne-Twister RNG status variables
unsigned int mt[N]; // the array for the state vector unsigned int mt[N]; // the array for the state vector
int mti; int mti;
// construction // construction
public: public:
// ctor // ctor
MarsenneTwisterRNG() MarsenneTwisterRNG()
{ {
initialize(5489u); initialize(5489u);
} }
// public methods // public methods
public: public:
/// (Re-)initialize with the given seed. /// (Re-)initialize with the given seed.
void initialize(unsigned int seed) void initialize(unsigned int seed)
{ {
mt[0]= seed & 0xffffffffu; mt[0]= seed & 0xffffffffu;
for (mti=1; mti<N; mti++) for (mti=1; mti<N; mti++)
{ {
mt[mti] = (1812433253u * (mt[mti-1] ^ (mt[mti-1] >> 30)) + mti); mt[mti] = (1812433253u * (mt[mti-1] ^ (mt[mti-1] >> 30)) + mti);
/* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */ /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
/* In the previous versions, MSBs of the seed affect */ /* In the previous versions, MSBs of the seed affect */
/* only MSBs of the array mt[]. */ /* only MSBs of the array mt[]. */
/* 2002/01/09 modified by Makoto Matsumoto */ /* 2002/01/09 modified by Makoto Matsumoto */
mt[mti] &= 0xffffffffu; mt[mti] &= 0xffffffffu;
/* for >32 bit machines */ /* for >32 bit machines */
} }
} }
/** /**
* Initialize by an array with array-length. * Initialize by an array with array-length.
* *
* init_key is the array for initializing keys * init_key is the array for initializing keys
* key_length is its length * key_length is its length
*/ */
void initializeByArray(unsigned int init_key[], int key_length) void initializeByArray(unsigned int init_key[], int key_length)
{ {
int i, j, k; int i, j, k;
initialize(19650218u); initialize(19650218u);
i=1; j=0; i=1; j=0;
k = (N>key_length ? N : key_length); k = (N>key_length ? N : key_length);
for (; k; k--) for (; k; k--)
{ {
mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1664525u)) + init_key[j] + j; /* non linear */ mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1664525u)) + init_key[j] + j; /* non linear */
mt[i] &= 0xffffffffu; /* for WORDSIZE > 32 machines */ mt[i] &= 0xffffffffu; /* for WORDSIZE > 32 machines */
i++; j++; i++; j++;
if (i>=N) if (i>=N)
{ {
mt[0] = mt[N-1]; mt[0] = mt[N-1];
i=1; i=1;
} }
if (j>=key_length) j=0; if (j>=key_length) j=0;
} }
for (k=N-1; k; k--) for (k=N-1; k; k--)
{ {
mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1566083941u)) - i; /* non linear */ mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1566083941u)) - i; /* non linear */
mt[i] &= 0xffffffffu; /* for WORDSIZE > 32 machines */ mt[i] &= 0xffffffffu; /* for WORDSIZE > 32 machines */
i++; i++;
if (i>=N) if (i>=N)
{ {
mt[0] = mt[N-1]; mt[0] = mt[N-1];
i=1; i=1;
} }
} }
mt[0] = 0x80000000u; /* MSB is 1; assuring non-zero initial array */ mt[0] = 0x80000000u; /* MSB is 1; assuring non-zero initial array */
} }
/** /**
* Return a random number in the [0,0xffffffff] interval using the improved Marsenne Twister algorithm. * Return a random number in the [0,0xffffffff] interval using the improved Marsenne Twister algorithm.
* *
* NOTE: Limit is not considered, the interval is fixed. * NOTE: Limit is not considered, the interval is fixed.
*/ */
unsigned int generate(unsigned int limit) unsigned int generate(unsigned int limit)
{ {
unsigned int y; unsigned int y;
static unsigned int mag01[2]={0x0u, MATRIX_A}; static unsigned int mag01[2]={0x0u, MATRIX_A};
/* mag01[x] = x * MATRIX_A for x=0,1 */ /* mag01[x] = x * MATRIX_A for x=0,1 */
if (mti >= N) // generate N words at one time if (mti >= N) // generate N words at one time
{ {
int kk; int kk;
for (kk=0;kk<N-M;kk++) for (kk=0;kk<N-M;kk++)
{ {
y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK); y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
mt[kk] = mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1u]; mt[kk] = mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1u];
} }
for (;kk<N-1;kk++) for (;kk<N-1;kk++)
{ {
y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK); y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
mt[kk] = mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1u]; mt[kk] = mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1u];
} }
y = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK); y = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK);
mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1u]; mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1u];
mti = 0; mti = 0;
} }
y = mt[mti++]; y = mt[mti++];
/* Tempering */ /* Tempering */
y ^= (y >> 11); y ^= (y >> 11);
y ^= (y << 7) & 0x9d2c5680u; y ^= (y << 7) & 0x9d2c5680u;
y ^= (y << 15) & 0xefc60000u; y ^= (y << 15) & 0xefc60000u;
y ^= (y >> 18); y ^= (y >> 18);
return y; return y;
} }
/// Returns a random number in the [0,1] real interval using the improved Marsenne-Twister. /// Returns a random number in the [0,1] real interval using the improved Marsenne-Twister.
double generate01closed() double generate01closed()
{ {
return generate(0)*(1.0/4294967295.0); return generate(0)*(1.0/4294967295.0);
} }
/// Returns a random number in the [0,1) real interval using the improved Marsenne-Twister. /// Returns a random number in the [0,1) real interval using the improved Marsenne-Twister.
double generate01() double generate01()
{ {
return generate(0)*(1.0/4294967296.0); return generate(0)*(1.0/4294967296.0);
} }
/// Generates a random number in the (0,1) real interval using the improved Marsenne-Twister. /// Generates a random number in the (0,1) real interval using the improved Marsenne-Twister.
double generate01open() double generate01open()
{ {
return (((double)generate(0)) + 0.5)*(1.0/4294967296.0); return (((double)generate(0)) + 0.5)*(1.0/4294967296.0);
} }
}; };
} // end namespace math } // end namespace math
} // end namespace vcg } // end namespace vcg
/* /*
Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura, Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
All rights reserved. All rights reserved.
Redistribution and use in source and binary forms, with or without Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions modification, are permitted provided that the following conditions
are met: are met:
1. Redistributions of source code must retain the above copyright 1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer. notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright 2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution. documentation and/or other materials provided with the distribution.
3. The names of its contributors may not be used to endorse or promote 3. The names of its contributors may not be used to endorse or promote
products derived from this software without specific prior written products derived from this software without specific prior written
permission. permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/ */
#endif /* __VCG_RandomGenerator */ #endif /* __VCG_RandomGenerator */