On 07/31/2012 11:47 AM, Sergey Mitsyn wrote:
On 29.07.2012 6:31, Dave Abrahams wrote:
on Thu Jul 12 2012, Karsten Ahnert <karsten.ahnert-AT-ambrosys.de> wrote:
On 07/12/2012 09:52 AM, Mario Mulansky wrote:
On Wed, 2012-07-11 at 23:50 -0700, Jeffrey Lee Hellrung, Jr. wrote:
I agree that it1 != it2 should be implemented in the sense of t1+-dt/2 != t2+-dt/2
So you are checking for overlap. This looks good and I think it should work.
If I'm understanding correctly what you're saying, making two iterators equal if their underlying time ranges overlap would be "evil." Your equality operator would not be transitive, and thus not an equivalence relation, and therefore you would not have implemented a conforming iterator, and you'd have no right to expect an algorithm that works on iterators to work on yours.
IMHO the values of the iterator's underlying time variable would belong to "almost" discrete {t0 + n*dt +/- epsilon}, n from Z, where epsilon comes from floating point errors and is small. Thus, the distance between neighboring values should be no less than (dt-2*epsilon).
Shouldn't this be t0 + n*dt +/- n*epsilon? I think the error scales with N, or even sqrt(N)?
I would say a test 'distance(t1,t2) < dt/2' would be transitive if epsilon is less than dt/4
That's of course true while t0 and dt is the same for all iterators passed to an algorithm.
But maybe in my fast skimming I've failed to grasp what's going on.