Re: [Boost-bugs] [Boost C++ Libraries] #10127: coordinate_matrix sort() fails on to std::swap

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #10127: coordinate_matrix sort() fails on to std::swap
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2014-06-27 06:25:54

#10127: coordinate_matrix sort() fails on to std::swap
-------------------------------+---------------------
  Reporter:  anonymous         |      Owner:
      Type:  Bugs              |     Status:  new
 Milestone:  To Be Determined  |  Component:  None
   Version:  Boost 1.54.0      |   Severity:  Problem
Resolution:                    |   Keywords:
-------------------------------+---------------------

Comment (by Andrew Medlin <amedlin@…>):

 This also affects version 1.55.0 sparse vectors, which breaks the LU
 substitution.

 For example, the following code produces incorrect output.  It should swap
 the 2nd and 3rd elements, producing
     1.000000,  3.000000,  2.000000
 but instead it produces
     1.000000,  3.000000,  3.000000

 It is fixed by uncommenting the #define BOOST_UBLAS_NO_ELEMENT_PROXIES

 {{{
 //#define BOOST_UBLAS_NO_ELEMENT_PROXIES

 #include <boost/numeric/ublas/vector_sparse.hpp>
 #include <boost/numeric/ublas/lu.hpp>

 using namespace boost::numeric::ublas;

 int main()
 {
     mapped_vector<float> y;
     y(0) = 1.0f;
     y(1) = 2.0f;
     y(2) = 3.0f;
     LOG("Initial vector is: " << y);
     permutation_matrix<std::size_t> perm(y.size());
     perm(0) = 0;
     perm(1) = 2;
     perm(2) = 2;
     swap_rows(perm, y);
     LOG("Swapped vector is: " << y);
 }
 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/10127#comment:2>
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