Re: [Boost-bugs] [Boost C++ Libraries] #688: ublas: bug in mapped_vector_of_mapped_vector

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #688: ublas: bug in mapped_vector_of_mapped_vector
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2007-09-24 21:29:48

#688: ublas: bug in mapped_vector_of_mapped_vector
---------------------+------------------------------------------------------
  Reporter:  troyer  |       Owner:  guwi17 
      Type:  Bugs    |      Status:  closed 
 Milestone:          |   Component:  uBLAS  
   Version:  None    |    Severity:  Problem
Resolution:  fixed   |    Keywords:         
---------------------+------------------------------------------------------
Changes (by guwi17):

  * status:  new => closed
  * resolution:  None => fixed

Comment:

 patch commited to SVN. See thread "Serious bug in
 mapped_vector_of_mapped_vector" of uBLAS mailing list (from sept. 2006!)

 On Thursday 07 September 2006 14:04, Gunter Winkler wrote:
 > On Sunday 23 July 2006 11:13, Matthias Troyer wrote:
 > > There is a serious bug in the mapped_vector_of_mapped_vector spare
 > > matrix type. Rows containing only zero elements are not treated
 > > correctly in prod(). The following code should give a vector that
 > > contains only 1 in the last element. Instead prod() gives a vector
 > > containing 1 in each element. In debug mode this bug is found by the
 >
 > I could reproduce the bug. It is inside the vector_assign logic. The
 > product is correctly computed, but the assignment fails. I will give
 more
 > details shortly.

 I finally found the bug and (hopefully) fixed it. The patch and sample
 program
 is attached. Is someone using mapped_vector_of_mapped_vector in a larger
 program? I'd like to know if the changes have any unexpected side affect.

 I changed the behavior of the iterators: Even the outer iterators skip
 empty
 rows (or columns).

-- 
Ticket URL: <http://svn.boost.org/trac/boost/ticket/688#comment:2>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.