1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
|
/*
* 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;
}
|
