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+// 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: sameeragarwal@google.com (Sameer Agarwal)
+
+#ifndef CERES_EXAMPLES_RANDOM_H_
+#define CERES_EXAMPLES_RANDOM_H_
+
+#include <math.h>
+#include <stdlib.h>
+
+namespace ceres {
+namespace examples {
+
+// Return a random number sampled from a uniform distribution in the range
+// [0,1].
+inline double RandDouble() {
+ double r = static_cast<double>(rand());
+ return r / RAND_MAX;
+}
+
+// Marsaglia Polar method for generation standard normal (pseudo)
+// random numbers http://en.wikipedia.org/wiki/Marsaglia_polar_method
+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 examples
+} // namespace ceres
+
+#endif // CERES_EXAMPLES_RANDOM_H_