| //===----------------------------------------------------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is dual licensed under the MIT and the University of Illinois Open |
| // Source Licenses. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // <random> |
| |
| // template<class RealType = double> |
| // class cauchy_distribution |
| |
| // template<class _URNG> result_type operator()(_URNG& g, const param_type& parm); |
| |
| #include <random> |
| #include <cassert> |
| #include <vector> |
| #include <algorithm> |
| |
| double |
| f(double x, double a, double b) |
| { |
| return 1/3.1415926535897932 * std::atan((x - a)/b) + .5; |
| } |
| |
| int main() |
| { |
| { |
| typedef std::cauchy_distribution<> D; |
| typedef D::param_type P; |
| typedef std::mt19937 G; |
| G g; |
| const double a = 10; |
| const double b = .5; |
| D d; |
| P p(a, b); |
| const int N = 1000000; |
| std::vector<D::result_type> u; |
| for (int i = 0; i < N; ++i) |
| u.push_back(d(g, p)); |
| std::sort(u.begin(), u.end()); |
| for (int i = 0; i < N; ++i) |
| assert(std::abs(f(u[i], a, b) - double(i)/N) < .001); |
| } |
| { |
| typedef std::cauchy_distribution<> D; |
| typedef D::param_type P; |
| typedef std::mt19937 G; |
| G g; |
| const double a = -1.5; |
| const double b = 1; |
| D d; |
| P p(a, b); |
| const int N = 1000000; |
| std::vector<D::result_type> u; |
| for (int i = 0; i < N; ++i) |
| u.push_back(d(g, p)); |
| std::sort(u.begin(), u.end()); |
| for (int i = 0; i < N; ++i) |
| assert(std::abs(f(u[i], a, b) - double(i)/N) < .001); |
| } |
| { |
| typedef std::cauchy_distribution<> D; |
| typedef D::param_type P; |
| typedef std::mt19937 G; |
| G g; |
| const double a = .5; |
| const double b = 2; |
| D d; |
| P p(a, b); |
| const int N = 1000000; |
| std::vector<D::result_type> u; |
| for (int i = 0; i < N; ++i) |
| u.push_back(d(g, p)); |
| std::sort(u.begin(), u.end()); |
| for (int i = 0; i < N; ++i) |
| assert(std::abs(f(u[i], a, b) - double(i)/N) < .001); |
| } |
| } |