91 lines
3.2 KiB
C++
91 lines
3.2 KiB
C++
/*
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Copyright (c) 2009-2010 Christopher A. Taylor. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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* Neither the name of LibCat nor the names of its contributors may be used
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to endorse or promote products derived from this software without
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specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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Algorithm by Makoto Matsumoto
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http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
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*/
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#ifndef CAT_MERSENNE_TWISTER_HPP
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#define CAT_MERSENNE_TWISTER_HPP
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#include <cat/rand/IRandom.hpp>
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namespace cat {
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// Noncryptographic pseudo-random number generator
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class MersenneTwister : public IRandom
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{
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static const u32 MEXP = 19937;
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static const u32 N128 = MEXP/128 + 1;
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static const u32 N64 = N128 * 2;
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static const u32 N32 = N128 * 4;
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static const u32 POS1 = 122;
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static const u32 SL1 = 18;
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static const u32 SL2 = 1;
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static const u32 SL2BITS = SL2*8;
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static const u32 SR1 = 11;
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static const u32 SR2 = 1;
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static const u32 SR2BITS = SR2*8;
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static const u32 MSK1 = 0xdfffffefU;
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static const u32 MSK2 = 0xddfecb7fU;
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static const u32 MSK3 = 0xbffaffffU;
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static const u32 MSK4 = 0xbffffff6U;
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struct MT128 {
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u32 u[4];
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};
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MT128 state[19937/128 + 1];
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u32 *state32;
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u32 used;
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CAT_INLINE void shiftLeft128(MT128 *r, MT128 *n, u32 bits);
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CAT_INLINE void shiftRight128(MT128 *r, MT128 *n, u32 bits);
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void enforcePeriod(); // make corrections to ensure that the generator has the full period
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void round(MT128 *a, MT128 *b, MT128 *c, MT128 *d); // a = MTMIX(a,b,c,d)
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void update(); // permute the existing state into a new one
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public:
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MersenneTwister();
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bool Initialize(u32 seed);
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bool Initialize(u32 *seeds, u32 words);
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bool Initialize();
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u32 Generate(); // generate a 32-bit number
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void Generate(void *buffer, int bytes); // generate a series of random numbers
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};
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} // namespace cat
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#endif // CAT_MERSENNE_TWISTER_HPP
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