1 // Ceres Solver - A fast non-linear least squares minimizer 2 // Copyright 2010, 2011, 2012 Google Inc. All rights reserved. 3 // http://code.google.com/p/ceres-solver/ 4 // 5 // Redistribution and use in source and binary forms, with or without 6 // modification, are permitted provided that the following conditions are met: 7 // 8 // * Redistributions of source code must retain the above copyright notice, 9 // this list of conditions and the following disclaimer. 10 // * Redistributions in binary form must reproduce the above copyright notice, 11 // this list of conditions and the following disclaimer in the documentation 12 // and/or other materials provided with the distribution. 13 // * Neither the name of Google Inc. nor the names of its contributors may be 14 // used to endorse or promote products derived from this software without 15 // specific prior written permission. 16 // 17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 18 // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 21 // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 22 // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 23 // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 24 // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 25 // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 26 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 27 // POSSIBILITY OF SUCH DAMAGE. 28 // 29 // Author: keir (at) google.com (Keir Mierle) 30 // sameeragarwal (at) google.com (Sameer Agarwal) 31 32 #ifndef CERES_INTERNAL_RANDOM_H_ 33 #define CERES_INTERNAL_RANDOM_H_ 34 35 #include <cmath> 36 #include <cstdlib> 37 #include "ceres/internal/port.h" 38 39 namespace ceres { 40 41 inline void SetRandomState(int state) { 42 srand(state); 43 } 44 45 inline int Uniform(int n) { 46 return rand() % n; 47 } 48 49 inline double RandDouble() { 50 double r = static_cast<double>(rand()); 51 return r / RAND_MAX; 52 } 53 54 // Box-Muller algorithm for normal random number generation. 55 // http://en.wikipedia.org/wiki/Box-Muller_transform 56 inline double RandNormal() { 57 double x1, x2, w; 58 do { 59 x1 = 2.0 * RandDouble() - 1.0; 60 x2 = 2.0 * RandDouble() - 1.0; 61 w = x1 * x1 + x2 * x2; 62 } while ( w >= 1.0 || w == 0.0 ); 63 64 w = sqrt((-2.0 * log(w)) / w); 65 return x1 * w; 66 } 67 68 } // namespace ceres 69 70 #endif // CERES_INTERNAL_RANDOM_H_ 71
