[Boost-bugs] [Boost C++ Libraries] #5298: Normal distribution: copy constructor doesn't yield intuitive correct behavior

Subject: [Boost-bugs] [Boost C++ Libraries] #5298: Normal distribution: copy constructor doesn't yield intuitive correct behavior
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-03-13 14:03:26

#5298: Normal distribution: copy constructor doesn't yield intuitive correct
behavior
-------------------------------------------------+--------------------------
 Reporter:  Stefan Maagh <s.maagh@…>             |       Owner:  steven_watanabe
     Type:  Bugs                                 |      Status:  new            
Milestone:  To Be Determined                     |   Component:  random         
  Version:  Boost 1.46.0                         |    Severity:  Problem        
 Keywords:                                       |  
-------------------------------------------------+--------------------------
 Purging the cache in the copy constructor of normal_distribution is not
 fine. The compiler generated copy constructor yields the correct behavior.

 In the attached example a generator (A) using normal_distribution is
 called once before a generator (B) is created as a copy of (A). The
 expected behavior is that calling (A) and (B) now produces identical
 sequences. But they don't.

 The attached example shows that using uniform_int instead
 normal_distribution yields the expected behavior.

 Applying the compiler generated copy constructor worked fine for me. Well,
 I expect that there was a reason to purge the cache although I can't see
 it. But for consistence and to provide intuitive correct behavior I
 suggest to apply the compiler generated copy constructor.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/5298>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.