b64f8b07c1
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@119395 91177308-0d34-0410-b5e6-96231b3b80d8
79 lines
2.1 KiB
C++
79 lines
2.1 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// <random>
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// template<class RealType = double>
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// class cauchy_distribution
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// template<class _URNG> result_type operator()(_URNG& g);
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#include <random>
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#include <cassert>
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#include <vector>
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#include <algorithm>
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double
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f(double x, double a, double b)
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{
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return 1/3.1415926535897932 * std::atan((x - a)/b) + .5;
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}
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int main()
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{
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{
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typedef std::cauchy_distribution<> D;
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typedef D::param_type P;
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typedef std::mt19937 G;
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G g;
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const double a = 10;
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const double b = .5;
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D d(a, b);
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const int N = 1000000;
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std::vector<D::result_type> u;
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for (int i = 0; i < N; ++i)
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u.push_back(d(g));
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std::sort(u.begin(), u.end());
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for (int i = 0; i < N; ++i)
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assert(std::abs(f(u[i], a, b) - double(i)/N) < .001);
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}
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{
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typedef std::cauchy_distribution<> D;
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typedef D::param_type P;
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typedef std::mt19937 G;
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G g;
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const double a = -1.5;
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const double b = 1;
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D d(a, b);
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const int N = 1000000;
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std::vector<D::result_type> u;
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for (int i = 0; i < N; ++i)
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u.push_back(d(g));
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std::sort(u.begin(), u.end());
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for (int i = 0; i < N; ++i)
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assert(std::abs(f(u[i], a, b) - double(i)/N) < .001);
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}
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{
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typedef std::cauchy_distribution<> D;
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typedef D::param_type P;
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typedef std::mt19937 G;
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G g;
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const double a = .5;
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const double b = 2;
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D d(a, b);
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const int N = 1000000;
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std::vector<D::result_type> u;
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for (int i = 0; i < N; ++i)
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u.push_back(d(g));
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std::sort(u.begin(), u.end());
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for (int i = 0; i < N; ++i)
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assert(std::abs(f(u[i], a, b) - double(i)/N) < .001);
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}
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}
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