// (C) Copyright Nick Thompson 2020. // (C) Copyright John Maddock 2020. // 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 #include #include #include #include #include using boost::math::tools::ulps_plot; int main() { using PreciseReal = boost::multiprecision::mpfr_float_100; using CoarseReal = boost::multiprecision::cpp_bin_float_50; typedef boost::math::policies::policy< boost::math::policies::promote_float, boost::math::policies::promote_double > no_promote_policy; auto ai_coarse = [](CoarseReal const& x)->CoarseReal { return sin(x); }; auto ai_precise = [](PreciseReal const& x)->PreciseReal { return sin(x); }; std::string filename = "cpp_bin_float_sin.svg"; int samples = 100000; // How many pixels wide do you want your .svg? int width = 700; // Near a root, we have unbounded relative error. So for functions with roots, we define an ULP clip: PreciseReal clip = 50; // Should we perturb the abscissas? i.e., should we compute the high precision function f at x, // and the low precision function at the nearest representable x̂ to x? // Or should we compute both the high precision and low precision function at a low precision representable x̂? bool perturb_abscissas = false; auto plot = ulps_plot(ai_precise, CoarseReal(-20), CoarseReal(20), samples, perturb_abscissas); // Note the argument chaining: plot./*clip(clip).*/width(width); plot.background_color("white").font_color("black"); // Sometimes it's useful to set a title, but in many cases it's more useful to just use a caption. std::string title = "sin ULP plot with cpp_bin_float_50"; plot.title(title); plot.vertical_lines(6); plot.add_fn(ai_coarse); // You can write the plot to a stream: //std::cout << plot; // Or to a file: plot.write(filename); }