libstdc++-v3/testsuite/26_numerics/random/piecewise_constant_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) 2008-2020 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 // 26.4.8.5.2 Class template piecewise_constant_distribution
  24 // [rand.dist.samp.pconst]
  25 // 26.4.2.4 Concept RandomNumberDistribution [rand.concept.dist]
  26
  27 #include <random>
  28 #include <cmath>
  29 #include <testsuite_hooks.h>
  30
  31 struct cosine_distribution
  32 {
  33     cosine_distribution(double x0, double lambda)
  34     : _M_x0(x0), _M_lambda(lambda)
  35     { }
  36
  37     double
  38     operator()(double x)
  39     {
  40       if (x - _M_x0 < -_M_lambda / 4)
  41         return 0.0;
  42       else if (x - _M_x0 > _M_lambda / 4)
  43         return 0.0;
  44       else
  45         {
  46           const double pi = 3.14159265358979323846;
  47           return std::cos(2 * pi * (x - _M_x0) / _M_lambda);
  48         }
  49     }
  50
  51 private:
  52     double _M_x0;
  53     double _M_lambda;
  54 };
  55
  56 void
  57 test01()
  58 {
  59   cosine_distribution cd(1.5, 3.0);
  60   std::piecewise_constant_distribution<> u(21, -10.0, 10.0, cd);
  61   std::vector<double> interval = u.intervals();
  62   std::vector<double> density = u.densities();
  63   VERIFY( interval.size() == 22 );
  64   VERIFY( density.size() == 21 );
  65 }
  66
  67 int main()
  68 {
  69   test01();
  70   return 0;
  71 }