Re: [Boost-bugs] [Boost C++ Libraries] #5482: iterative_size() not the same for interval_maps using std::less and std::greater

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #5482: iterative_size() not the same for interval_maps using std::less and std::greater
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-04-17 16:50:32

#5482: iterative_size() not the same for interval_maps using std::less and
std::greater
-------------------------------------+--------------------------------------
  Reporter:  boicotinho@…            |       Owner:  jofaber                      
      Type:  Bugs                    |      Status:  assigned                     
 Milestone:  Boost 1.47.0            |   Component:  ICL                          
   Version:  Boost 1.46.1            |    Severity:  Problem                      
Resolution:                          |    Keywords:  interval, iteration, ordering
-------------------------------------+--------------------------------------

Comment (by jofaber):

 Replying to [comment:3 anonymous]:
 > Replying to [comment:2 jofaber]:
 >
 > Thank you for looking into this -
 > I really like this ICL of yours and use it a lot :)

 That's nice to hear. For me it is good to have users who are challenging
 the library or use it creative ways, so we can detect flaws and improve
 the code.

 > FYI It seems that your workaround works - but if
 > I insert the intervals in another order for m2,
 > then m2.find() fails while m1.find() still works.

 True, I suspected you'd find some more problems using std::greater. I have
 found and fixed more inconsistencies between compare-order and
 incrementation/decrementation that caused these program failures and
 committed the improved code to the boost/trunk. You might want to get a
 copy of that code if you like. I am still doing some testing though before
 closing the ticket.

 > In the meanwhile I am using std::less but representing
 > the data with negative numbers instead.
 >
 > The reason I wanted to use std::greater is because
 > I would like find() to start from the highest interval
 > given a range.

 To find the last interval that overlaps a given interval `I` you could use
 `it = m.upper_bound(I)`, which yields an iterator to the first interval
 that is greater than I and then decrement the iterator `it` once.

 Cheers,
 Joachim

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/5482#comment:4>
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