65 lines
2.4 KiB
C
65 lines
2.4 KiB
C
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// Ceres Solver - A fast non-linear least squares minimizer
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// Copyright 2015 Google Inc. All rights reserved.
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// http://ceres-solver.org/
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are met:
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//
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// * Redistributions of source code must retain the above copyright notice,
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// this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above copyright notice,
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// this list of conditions and the following disclaimer in the documentation
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// and/or other materials provided with the distribution.
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// * Neither the name of Google Inc. nor the names of its contributors may be
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// used to endorse or promote products derived from this software without
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// specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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// POSSIBILITY OF SUCH DAMAGE.
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//
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// Author: sameeragarwal@google.com (Sameer Agarwal)
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#ifndef CERES_EXAMPLES_RANDOM_H_
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#define CERES_EXAMPLES_RANDOM_H_
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#include <math.h>
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#include <stdlib.h>
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namespace ceres {
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namespace examples {
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// Return a random number sampled from a uniform distribution in the range
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// [0,1].
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inline double RandDouble() {
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double r = static_cast<double>(rand());
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return r / RAND_MAX;
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}
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// Marsaglia Polar method for generation standard normal (pseudo)
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// random numbers http://en.wikipedia.org/wiki/Marsaglia_polar_method
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inline double RandNormal() {
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double x1, x2, w;
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do {
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x1 = 2.0 * RandDouble() - 1.0;
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x2 = 2.0 * RandDouble() - 1.0;
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w = x1 * x1 + x2 * x2;
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} while ( w >= 1.0 || w == 0.0 );
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w = sqrt((-2.0 * log(w)) / w);
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return x1 * w;
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}
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} // namespace examples
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} // namespace ceres
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#endif // CERES_EXAMPLES_RANDOM_H_
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