libstdc++-v3/testsuite/26_numerics/random/discrete_distribution/cons/num_xbound_fun.cc

   1 // { dg-do run { target c++11 } }
   2 // { dg-require-cstdint "" }
   3 //
   4 // 2008-12-03  Edward M. Smith-Rowland <3dw4rd@verizon.net>
   5 //
   6 // Copyright (C) 2008-2023 Free Software Foundation, Inc.
   7 //
   8 // This file is part of the GNU ISO C++ Library.  This library is free
   9 // software; you can redistribute it and/or modify it under the
  10 // terms of the GNU General Public License as published by the
  11 // Free Software Foundation; either version 3, or (at your option)
  12 // any later version.
  13 //
  14 // This library is distributed in the hope that it will be useful,
  15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 // GNU General Public License for more details.
  18 //
  19 // You should have received a copy of the GNU General Public License along
  20 // with this library; see the file COPYING3.  If not see
  21 // <http://www.gnu.org/licenses/>.
  22
  23 // 26.4.8.5.1 Class template discrete_distribution [rand.dist.samp.discrete]
  24 // 26.4.2.4 Concept RandomNumberDistribution [rand.concept.dist]
  25
  26 #include <random>
  27 #include <cmath>
  28 #include <testsuite_hooks.h>
  29
  30 struct cosine_distribution
  31 {
  32     cosine_distribution(double x0, double lambda)
  33     : _M_x0(x0), _M_lambda(lambda)
  34     { }
  35
  36     double
  37     operator()(double x)
  38     {
  39       if (x - _M_x0 < -_M_lambda / 4)
  40         return 0.0;
  41       else if (x - _M_x0 > _M_lambda / 4)
  42         return 0.0;
  43       else
  44         {
  45           const double pi = 3.14159265358979323846;
  46           return std::cos(2 * pi * (x - _M_x0) / _M_lambda);
  47         }
  48     }
  49
  50 private:
  51     double _M_x0;
  52     double _M_lambda;
  53 };
  54
  55 void
  56 test01()
  57 {
  58   cosine_distribution cd(1.5, 3.0);
  59   std::discrete_distribution<> u(21, -10.0, 10.0, cd);
  60   std::vector<double> probablility = u.probabilities();
  61   VERIFY( probablility.size() == 21 );
  62 }
  63
  64 int main()
  65 {
  66   test01();
  67   return 0;
  68 }