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@google.com (Keir Mierle) 30// sameeragarwal@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 39namespace ceres { 40 41inline void SetRandomState(int state) { 42 srand(state); 43} 44 45inline int Uniform(int n) { 46 return rand() % n; 47} 48 49inline 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 56inline 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