Bronek Kozicki ha scritto:
Alberto Ganesh Barbati wrote:
template <typename T> struct compare_absolute_error : std::binary_function<T, T, bool>
bool operator()(T x, T y) const { return abs(x - y) < eps; } 1) Is there interest for this?
I'm not math expert, but I certainly agree that such utility would be useful. However, as some standard algorithms need equality comparison, while containers need less-than comparison, it would be nice to provide at least then both, and make names obvious enough.
I believe less-than comparison are not very useful, in fact. That's because whatever fuzzy algorithm you use, the induced relation won't be transitive, so it won't induce a strict-weak ordering. It's true that also fuzzy equality does not induce an equivalence relation for the same reason, yet the fuzzy equality is still useful even in absence of that requirement.
2) What are the comparison algorithms to include?
good question. But if comparision algorithm is a template parameter (policy class), we do not have to define them all in advance.
Well... if you already had the comparison algorithm to put in a template parameter, then you won't need a... comparison algorithm! The point here is exactly to provide a library of ready-made algorithms. Of course some details might be fine-tunable via policy classes, as suggested by John Maddock, but not the entire algorithm itself. Ganesh