Using portable math functions

Some projects require specific trigonometric functions, a library for numerically solving ordinary differential equations and working with distributions and constants. All those parts of Boost.Math will be hard to fit even in a separate book. A single recipe definitely won't be enough. So, let's focus on very basic everyday-use functions to work with float types.

We'll write a portable function that checks input value for infinity and Not-a-Number (NaN) values and changes the sign if the value is negative.

Getting ready

Basic knowledge of C++ is required for this recipe. Those who know C99 standard will find a lot common in this recipe.

How to do it...

Perform the following steps to check the input value for infinity and NaN values and change the sign if the value is negative:

1. We need the following headers:

#include <boost/math/special_functions.hpp> 
#include <cassert> 

2. Asserting for infinity and NaN can be done like this:

template <class T> 
void...