Re: [boost] [math] RFC: comparison function objects

From: David Abrahams (dave_at_[hidden])
Date: 2006-04-22 14:03:04

Alberto Ganesh Barbati <abarbati_at_[hidden]> writes:

> Hi Everybody,
>
> in a discussion on comp.std.c++ it was proposed to include into boost
> some facility to "fuzzy" or, in other words, to "properly" compare
> floating point numbers. Something like this, for example:
>
> template <typename T>
> struct compare_absolute_error : std::binary_function<T, T, bool>
> {
>   T eps;
>   compare_absolute_error(T eps_) : eps(eps_) {}
>   bool operator()(T x, T y) const { return abs(x - y) < eps; }
> };
>
> This kind of operators occurs frequently in algorithms and are sometimes
> error-prone to write, so having a ready-made and well tested component
> can certainly be an advantage.

There's something like this in the Boost.Test library.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com