// Ceres Solver - A fast non-linear least squares minimizer // Copyright 2015 Google Inc. All rights reserved. // http://ceres-solver.org/ // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are met: // // * Redistributions of source code must retain the above copyright notice, // this list of conditions and the following disclaimer. // * 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. // * Neither the name of Google Inc. nor the names of its contributors may 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. // // Author: keir@google.com (Keir Mierle) // sameeragarwal@google.com (Sameer Agarwal) #ifndef CERES_INTERNAL_RANDOM_H_ #define CERES_INTERNAL_RANDOM_H_ #include #include #include "ceres/internal/export.h" namespace ceres { inline void SetRandomState(int state) { srand(state); } inline int Uniform(int n) { if (n) { return rand() % n; } else { return 0; } } inline double RandDouble() { auto r = static_cast(rand()); return r / RAND_MAX; } // Box-Muller algorithm for normal random number generation. // http://en.wikipedia.org/wiki/Box-Muller_transform inline double RandNormal() { double x1, x2, w; do { x1 = 2.0 * RandDouble() - 1.0; x2 = 2.0 * RandDouble() - 1.0; w = x1 * x1 + x2 * x2; } while (w >= 1.0 || w == 0.0); w = sqrt((-2.0 * log(w)) / w); return x1 * w; } } // namespace ceres #endif // CERES_INTERNAL_RANDOM_H_