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- /*
- * Copyright Nick Thompson, 2019
- * Use, modification and distribution are subject to the
- * Boost Software License, Version 1.0. (See accompanying file
- * LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- */
- #include "math_unit_test.hpp"
- #include <numeric>
- #include <utility>
- #include <random>
- #include <cmath>
- #include <boost/core/demangle.hpp>
- #include <boost/math/special_functions/gegenbauer.hpp>
- #ifdef BOOST_HAS_FLOAT128
- #include <boost/multiprecision/float128.hpp>
- using boost::multiprecision::float128;
- #endif
- using std::abs;
- using boost::math::gegenbauer;
- using boost::math::gegenbauer_derivative;
- template<class Real>
- void test_parity()
- {
- std::mt19937 gen(323723);
- std::uniform_real_distribution<Real> xdis(-1, +1);
- std::uniform_real_distribution<Real> lambdadis(-0.5, 1);
- for(unsigned n = 0; n < 50; ++n) {
- unsigned calls = 50;
- unsigned i = 0;
- while(i++ < calls) {
- Real x = xdis(gen);
- Real lambda = lambdadis(gen);
- if (n & 1) {
- CHECK_ULP_CLOSE(gegenbauer(n, lambda, -x), -gegenbauer(n, lambda, x), 0);
- }
- else {
- CHECK_ULP_CLOSE(gegenbauer(n, lambda, -x), gegenbauer(n, lambda, x), 0);
- }
- }
- }
- }
- template<class Real>
- void test_quadratic()
- {
- Real lambda = 1/Real(4);
- auto c2 = [&](Real x) { return -lambda + 2*lambda*(1+lambda)*x*x; };
- Real x = -1;
- Real h = 1/Real(256);
- while (x < 1) {
- Real expected = c2(x);
- Real computed = gegenbauer(2, lambda, x);
- CHECK_ULP_CLOSE(expected, computed, 0);
- x += h;
- }
- }
- template<class Real>
- void test_cubic()
- {
- Real lambda = 1/Real(4);
- auto c3 = [&](Real x) { return lambda*(1+lambda)*x*(-2 + 4*(2+lambda)*x*x/3); };
- Real x = -1;
- Real h = 1/Real(256);
- while (x < 1) {
- Real expected = c3(x);
- Real computed = gegenbauer(3, lambda, x);
- CHECK_ULP_CLOSE(expected, computed, 4);
- x += h;
- }
- }
- template<class Real>
- void test_derivative()
- {
- Real lambda = 0.5;
- auto c3_prime = [&](Real x) { return 2*lambda*(lambda+1)*(-1 + 2*(lambda+2)*x*x); };
- auto c3_double_prime = [&](Real x) { return 8*lambda*(lambda+1)*(lambda+2)*x; };
- Real x = -1;
- Real h = 1/Real(256);
- while (x < 1) {
- Real expected = c3_prime(x);
- Real computed = gegenbauer_derivative(3, lambda, x, 1);
- CHECK_ULP_CLOSE(expected, computed, 1);
- expected = c3_double_prime(x);
- computed = gegenbauer_derivative(3, lambda, x, 2);
- CHECK_ULP_CLOSE(expected, computed, 1);
- x += h;
- }
- }
- int main()
- {
- test_parity<float>();
- test_parity<double>();
- test_parity<long double>();
- test_quadratic<float>();
- test_quadratic<double>();
- test_quadratic<long double>();
- test_cubic<double>();
- test_cubic<long double>();
- test_derivative<float>();
- test_derivative<double>();
- test_derivative<long double>();
- #ifdef BOOST_HAS_FLOAT128
- test_quadratic<boost::multiprecision::float128>();
- test_cubic<boost::multiprecision::float128>();
- #endif
- return boost::math::test::report_errors();
- }
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