1// Ceres Solver - A fast non-linear least squares minimizer 2// Copyright 2014 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: sameeragarwal@google.com (Sameer Agarwal) 30 31#ifndef CERES_EXAMPLES_RANDOM_H_ 32#define CERES_EXAMPLES_RANDOM_H_ 33 34#include <math.h> 35#include <stdlib.h> 36 37namespace ceres { 38namespace examples { 39 40// Return a random number sampled from a uniform distribution in the range 41// [0,1]. 42inline double RandDouble() { 43 double r = static_cast<double>(rand()); 44 return r / RAND_MAX; 45} 46 47// Marsaglia Polar method for generation standard normal (pseudo) 48// random numbers http://en.wikipedia.org/wiki/Marsaglia_polar_method 49inline double RandNormal() { 50 double x1, x2, w; 51 do { 52 x1 = 2.0 * RandDouble() - 1.0; 53 x2 = 2.0 * RandDouble() - 1.0; 54 w = x1 * x1 + x2 * x2; 55 } while ( w >= 1.0 || w == 0.0 ); 56 57 w = sqrt((-2.0 * log(w)) / w); 58 return x1 * w; 59} 60 61} // namespace examples 62} // namespace ceres 63 64#endif // CERES_EXAMPLES_RANDOM_H_ 65