math/example/lambert_w_basic_example.cpp at develop · boostandroid/math

30 lines (25 loc) · 1.2 KB

// Copyright Paul A. Bristow 2018

// Distributed under 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)

// Example of most basic call of both lambert W functions.

// Only requires C++03

// (and optionally a call of max_digits10 to show precision).

#include <boost/math/special_functions/lambert_w.hpp> // For lambert_w0 and wm1 functions.

#include <iostream>

#include <iomanip>

int main()

{

double z = 2.0;

double w0 = boost::math::lambert_w0(z);

std::cout.setf(std::ios_base::showpoint); // Include any trailing zeros.

std::cout.precision(std::numeric_limits<double>::max_digits10); // Show all possibly significant digits.

// Avoid using max_digfigs10 so as many old compilers can run the most basic lambert_w0 test?

// Require to get max_digits10

// [ run lambert_w_basic_example.cpp : : : [ requires cxx11_numeric_limits ] ]

std::cout << " lambert_w0(" << z << ") = " << w0 << std::endl; // lambert_w0(2.00000) = 0.852606

z = -0.2;

double wm1 = boost::math::lambert_wm1(z);

std::cout << " lambert_wm1(" << z << ") = " << wm1 << std::endl; // lambert_wm1(-0.200000) = -2.54264

return 0;

} // int main()

Provide feedback