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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// REQUIRES: long_tests
// <random>
// template<class RealType = double>
// class cauchy_distribution
// template<class _URNG> result_type operator()(_URNG& g);
#include <random>
#include <cassert>
#include <cmath>
#include <vector>
#include <algorithm>
#include "test_macros.h"
double
f(double x, double a, double b)
{
return 1/3.1415926535897932 * std::atan((x - a)/b) + .5;
}
int main(int, char**)
{
{
typedef std::cauchy_distribution<> D;
typedef std::mt19937 G;
G g;
const double a = 10;
const double b = .5;
D d(a, b);
const int N = 1000000;
std::vector<D::result_type> u;
for (int i = 0; i < N; ++i)
u.push_back(d(g));
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 std::mt19937 G;
G g;
const double a = -1.5;
const double b = 1;
D d(a, b);
const int N = 1000000;
std::vector<D::result_type> u;
for (int i = 0; i < N; ++i)
u.push_back(d(g));
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 std::mt19937 G;
G g;
const double a = .5;
const double b = 2;
D d(a, b);
const int N = 1000000;
std::vector<D::result_type> u;
for (int i = 0; i < N; ++i)
u.push_back(d(g));
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);
}
return 0;
}
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