math/test/cardinal_quadratic_b_spline_test.cpp

131 lines
3.2 KiB
C++

/*
* 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 <boost/math/interpolators/cardinal_quadratic_b_spline.hpp>
using boost::math::interpolators::cardinal_quadratic_b_spline;
template<class Real>
void test_constant()
{
Real c = 7.2;
Real t0 = 0;
Real h = Real(1)/Real(16);
size_t n = 512;
std::vector<Real> v(n, c);
auto qbs = cardinal_quadratic_b_spline<Real>(v.data(), v.size(), t0, h);
size_t i = 0;
while (i < n) {
Real t = t0 + i*h;
CHECK_ULP_CLOSE(c, qbs(t), 2);
CHECK_MOLLIFIED_CLOSE(0, qbs.prime(t), 100*std::numeric_limits<Real>::epsilon());
++i;
}
i = 0;
while (i < n) {
Real t = t0 + i*h + h/2;
CHECK_ULP_CLOSE(c, qbs(t), 2);
CHECK_MOLLIFIED_CLOSE(0, qbs.prime(t), 300*std::numeric_limits<Real>::epsilon());
t = t0 + i*h + h/4;
CHECK_ULP_CLOSE(c, qbs(t), 2);
CHECK_MOLLIFIED_CLOSE(0, qbs.prime(t), 150*std::numeric_limits<Real>::epsilon());
++i;
}
}
template<class Real>
void test_linear()
{
Real m = 8.3;
Real b = 7.2;
Real t0 = 0;
Real h = Real(1)/Real(16);
size_t n = 512;
std::vector<Real> y(n);
for (size_t i = 0; i < n; ++i) {
Real t = i*h;
y[i] = m*t + b;
}
auto qbs = cardinal_quadratic_b_spline<Real>(y.data(), y.size(), t0, h);
size_t i = 0;
while (i < n) {
Real t = t0 + i*h;
CHECK_ULP_CLOSE(m*t+b, qbs(t), 2);
CHECK_ULP_CLOSE(m, qbs.prime(t), 820);
++i;
}
i = 0;
while (i < n) {
Real t = t0 + i*h + h/2;
CHECK_ULP_CLOSE(m*t+b, qbs(t), 2);
CHECK_MOLLIFIED_CLOSE(m, qbs.prime(t), 1500*std::numeric_limits<Real>::epsilon());
t = t0 + i*h + h/4;
CHECK_ULP_CLOSE(m*t+b, qbs(t), 3);
CHECK_MOLLIFIED_CLOSE(m, qbs.prime(t), 1500*std::numeric_limits<Real>::epsilon());
++i;
}
}
template<class Real>
void test_quadratic()
{
Real a = 8.2;
Real b = 7.2;
Real c = -9.2;
Real t0 = 0;
Real h = Real(1)/Real(16);
size_t n = 513;
std::vector<Real> y(n);
for (size_t i = 0; i < n; ++i) {
Real t = i*h;
y[i] = a*t*t + b*t + c;
}
Real t_max = t0 + (n-1)*h;
auto qbs = cardinal_quadratic_b_spline<Real>(y, t0, h, b, 2*a*t_max + b);
size_t i = 0;
while (i < n) {
Real t = t0 + i*h;
CHECK_ULP_CLOSE(a*t*t + b*t + c, qbs(t), 2);
++i;
}
i = 0;
while (i < n) {
Real t = t0 + i*h + h/2;
CHECK_ULP_CLOSE(a*t*t + b*t + c, qbs(t), 47);
t = t0 + i*h + h/4;
if (!CHECK_ULP_CLOSE(a*t*t + b*t + c, qbs(t), 104)) {
std::cerr << " Problem abscissa t = " << t << "\n";
}
++i;
}
}
int main()
{
test_constant<float>();
test_constant<double>();
test_constant<long double>();
test_linear<float>();
test_linear<double>();
test_linear<long double>();
test_quadratic<double>();
test_quadratic<long double>();
return boost::math::test::report_errors();
}