From 484607fb6f0e4b54ebc83cf0f79a1159f7fe8cd7 Mon Sep 17 00:00:00 2001 From: Roman Donchenko Date: Wed, 10 Apr 2013 19:39:38 +0400 Subject: [PATCH] Backported RNG_MT19937 from master. --- modules/core/include/opencv2/core/core.hpp | 34 ++++++++ modules/core/src/rand.cpp | 125 +++++++++++++++++++++++++++++ modules/core/test/test_rand.cpp | 26 ++++++ 3 files changed, 185 insertions(+) diff --git a/modules/core/include/opencv2/core/core.hpp b/modules/core/include/opencv2/core/core.hpp index 1bffbaa..1c8e0e2 100644 --- a/modules/core/include/opencv2/core/core.hpp +++ b/modules/core/include/opencv2/core/core.hpp @@ -2044,6 +2044,40 @@ public: uint64 state; }; +/*! + Random Number Generator - MT + + The class implements RNG using the Mersenne Twister algorithm +*/ +class CV_EXPORTS RNG_MT19937 +{ +public: + RNG_MT19937(); + RNG_MT19937(unsigned s); + void seed(unsigned s); + + unsigned next(); + + operator int(); + operator unsigned(); + operator float(); + operator double(); + + unsigned operator ()(unsigned N); + unsigned operator ()(); + + //! returns uniformly distributed integer random number from [a,b) range + int uniform(int a, int b); + //! returns uniformly distributed floating-point random number from [a,b) range + float uniform(float a, float b); + //! returns uniformly distributed double-precision floating-point random number from [a,b) range + double uniform(double a, double b); + +private: + enum PeriodParameters {N = 624, M = 397}; + unsigned state[N]; + int mti; +}; /*! Termination criteria in iterative algorithms diff --git a/modules/core/src/rand.cpp b/modules/core/src/rand.cpp index bae8eae..2cdbe39 100644 --- a/modules/core/src/rand.cpp +++ b/modules/core/src/rand.cpp @@ -883,4 +883,129 @@ CV_IMPL void cvRandShuffle( CvArr* arr, CvRNG* _rng, double iter_factor ) cv::randShuffle( dst, iter_factor, &rng ); } +// Mersenne Twister random number generator. +// Inspired by http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/CODES/mt19937ar.c + +/* + A C-program for MT19937, with initialization improved 2002/1/26. + Coded by Takuji Nishimura and Makoto Matsumoto. + + Before using, initialize the state by using init_genrand(seed) + or init_by_array(init_key, key_length). + + Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura, + All rights reserved. + + 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. + + + Any feedback is very welcome. + http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html + email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space) +*/ + +cv::RNG_MT19937::RNG_MT19937(unsigned s) { seed(s); } + +cv::RNG_MT19937::RNG_MT19937() { seed(5489U); } + +void cv::RNG_MT19937::seed(unsigned s) +{ + state[0]= s; + for (mti = 1; mti < N; mti++) + { + /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */ + state[mti] = (1812433253U * (state[mti - 1] ^ (state[mti - 1] >> 30)) + mti); + } +} + +unsigned cv::RNG_MT19937::next() +{ + /* mag01[x] = x * MATRIX_A for x=0,1 */ + static unsigned mag01[2] = { 0x0U, /*MATRIX_A*/ 0x9908b0dfU}; + + const unsigned UPPER_MASK = 0x80000000U; + const unsigned LOWER_MASK = 0x7fffffffU; + + /* generate N words at one time */ + if (mti >= N) + { + int kk = 0; + + for (; kk < N - M; ++kk) + { + unsigned y = (state[kk] & UPPER_MASK) | (state[kk + 1] & LOWER_MASK); + state[kk] = state[kk + M] ^ (y >> 1) ^ mag01[y & 0x1U]; + } + + for (; kk < N - 1; ++kk) + { + unsigned y = (state[kk] & UPPER_MASK) | (state[kk + 1] & LOWER_MASK); + state[kk] = state[kk + (M - N)] ^ (y >> 1) ^ mag01[y & 0x1U]; + } + + unsigned y = (state[N - 1] & UPPER_MASK) | (state[0] & LOWER_MASK); + state[N - 1] = state[M - 1] ^ (y >> 1) ^ mag01[y & 0x1U]; + + mti = 0; + } + + unsigned y = state[mti++]; + + /* Tempering */ + y ^= (y >> 11); + y ^= (y << 7) & 0x9d2c5680U; + y ^= (y << 15) & 0xefc60000U; + y ^= (y >> 18); + + return y; +} + +cv::RNG_MT19937::operator unsigned() { return next(); } + +cv::RNG_MT19937::operator int() { return (int)next();} + +cv::RNG_MT19937::operator float() { return next() * (1.f / 4294967296.f); } + +cv::RNG_MT19937::operator double() +{ + unsigned a = next() >> 5; + unsigned b = next() >> 6; + return (a * 67108864.0 + b) * (1.0 / 9007199254740992.0); +} + +int cv::RNG_MT19937::uniform(int a, int b) { return (int)(next() % (b - a) + a); } + +float cv::RNG_MT19937::uniform(float a, float b) { return ((float)*this)*(b - a) + a; } + +double cv::RNG_MT19937::uniform(double a, double b) { return ((double)*this)*(b - a) + a; } + +unsigned cv::RNG_MT19937::operator ()(unsigned b) { return next() % b; } + +unsigned cv::RNG_MT19937::operator ()() { return next(); } + /* End of file. */ diff --git a/modules/core/test/test_rand.cpp b/modules/core/test/test_rand.cpp index e93415b..1d9b3dd 100644 --- a/modules/core/test/test_rand.cpp +++ b/modules/core/test/test_rand.cpp @@ -339,3 +339,29 @@ protected: TEST(Core_Rand, range) { Core_RandRangeTest test; test.safe_run(); } + +TEST(Core_RNG_MT19937, regression) +{ + cv::RNG_MT19937 rng; + int actual[61] = {0, }; + const size_t length = (sizeof(actual) / sizeof(actual[0])); + for (int i = 0; i < 10000; ++i ) + { + actual[(unsigned)(rng.next() ^ i) % length]++; + } + + int expected[length] = { + 177, 158, 180, 177, 160, 179, 143, 162, + 177, 144, 170, 174, 165, 168, 168, 156, + 177, 157, 159, 169, 177, 182, 166, 154, + 144, 180, 168, 152, 170, 187, 160, 145, + 139, 164, 157, 179, 148, 183, 159, 160, + 196, 184, 149, 142, 162, 148, 163, 152, + 168, 173, 160, 181, 172, 181, 155, 153, + 158, 171, 138, 150, 150 }; + + for (size_t i = 0; i < length; ++i) + { + ASSERT_EQ(expected[i], actual[i]); + } +} -- 2.7.4