Paul A Bristow wrote:
I was undecided about this: but for large intervals a std::difference_t wouldn't be large enough, for example edit_distance(0.0, 1.0) is approx 1.97753e+032. Of course if you use for intervals that stretch several orders of magnitude then you get what you deserve I guess!
I can see the problem here - Would you need a difference_t with about as many bits as the floating point type?
Yep indeed.
But I'm struggling to conceive of uses for this where the distance is so large? Perhaps someone can suggest some?
Well me too actually, although I can imagine some situations where you generate large numbers by accident: consider a measuring the error of a function where it's actually the absolute error that's low: in that situation you can easily generate arbitrary large results. In any case it's trivial to convert the floating point result to an integer if required (via the new rounding/truncation functions for example if you want error checking).
Can't the inevitable integer overflow just be accepted when it happens?
I also find the name edit_distance very unintuitive. In fact I struggle to see from how the definition in Wikipedia it is 'technically accurate'.
"In information theory and computer science, the edit distance between two strings of characters is the number of operations required to transform one of them into the other. There are several different algorithms to define or calculate this metric".
The idea was to invoke the idea of "how many operations are required to get from a to b".
In this case, don't we have a clearly defined *fixed* sequence of things each of which is 'iterated' from one value to another by calling a 'next' so many times. So the distance is a count of the number of 'nexts' - or gaps or steps or hops, or preds or succs. So it feels to me that the result is naturally an integer type. If you use T then it is OK for floating-point types (but loses exactness eventually), but precludes use for some types for which next_* functions do make sense but are not useful for an integer result.
Not sure I follow.
But I'm still struggling to find a better name, though 'nexts(a, b)' is short.
Um, what does "nexts" mean ? How about "intervals" or "representations" or "representation_count" or "interval_count" or... ? Cheers, John.