mirror of
https://github.com/boostorg/math.git
synced 2025-05-11 21:33:52 +00:00
4aac532a88
* Add Estrin's method for polynomial evaluation N.B.: This is a slightly modified version of the code provided by Thomas Dybdahl Ahle in a github issue. [CI SKIP] [ci skip] * Add comparisons to Horner with std::array. [CI SKIP] * Add Estrin's method for polynomial evaluation N.B.: This is a slightly modified version of the code provided by Thomas Dybdahl Ahle in a github issue. [CI SKIP] [ci skip] * Fix hang in n=0 case. * Fix out of bounds access in test. * Fix endsect for estrin.qbk. * Apply clang-format to make the 'inspect' stage happy. * Add type_traits header to includes. * Add ulp plot. * Document decreased accuracy of Estrin's method. * Add assertion for size of scratch pad * Remove std::size since it is C++17 * Add C++14 testing * estrin -> evaluate_polynomial_estrin. --------- Co-authored-by: jzmaddock <john@johnmaddock.co.uk> Co-authored-by: Matt Borland <matt@mattborland.com>
49 lines
1.7 KiB
C++
49 lines
1.7 KiB
C++
/*
|
|
* Copyright Thomas Dybdahl Ahle, Nick Thompson, Matt Borland, John Maddock, 2023
|
|
* 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 <boost/math/tools/estrin.hpp>
|
|
#include <boost/math/tools/rational.hpp>
|
|
#include <boost/math/tools/ulps_plot.hpp>
|
|
|
|
using boost::math::tools::evaluate_polynomial_estrin;
|
|
using boost::math::tools::evaluate_polynomial;
|
|
using boost::math::tools::ulps_plot;
|
|
|
|
void estrin_vs_horner(size_t n) {
|
|
std::random_device rd;
|
|
auto seed = rd();
|
|
std::mt19937_64 gen(seed);
|
|
std::uniform_real_distribution<float> dis(-1, 1);
|
|
std::vector<float> coeffs_float(n);
|
|
std::vector<double> coeffs_double(n);
|
|
for (size_t i = 0; i < n; ++i) {
|
|
coeffs_float[i] = dis(gen);
|
|
coeffs_double[i] = coeffs_float[i];
|
|
}
|
|
|
|
auto hi_acc = [&](double x) {
|
|
return evaluate_polynomial(coeffs_double.data(), x, coeffs_double.size());
|
|
};
|
|
auto estrin_float = [&](float x) { return evaluate_polynomial_estrin(coeffs_float, x); };
|
|
auto horner_float = [&](float x) {
|
|
return evaluate_polynomial(coeffs_float.data(), x, coeffs_float.size());
|
|
};
|
|
auto plot = ulps_plot<decltype(hi_acc), double, float>(hi_acc, float(-2.0),
|
|
float(2.0), 20000);
|
|
plot.ulp_envelope(true);
|
|
plot.add_fn(estrin_float, "steelblue");
|
|
plot.add_fn(horner_float, "orange");
|
|
plot.clip(10);
|
|
plot.title("Horner (orange) vs Estrin (blue) accuracy for a polynomial of degree " + std::to_string(n));
|
|
plot.write("horner_vs_estrin.svg");
|
|
}
|
|
|
|
int main() {
|
|
size_t n = 30;
|
|
estrin_vs_horner(n);
|
|
return 0;
|
|
}
|