[Boost-bugs] [Boost C++ Libraries] #2800: Bug in transposed_structure

Subject: [Boost-bugs] [Boost C++ Libraries] #2800: Bug in transposed_structure
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2009-02-25 20:01:50

#2800: Bug in transposed_structure
 Reporter: Tiago Requeijo | Owner: guwi17
     Type: Bugs | Status: new
Milestone: Boost 1.39.0 | Component: uBLAS
  Version: Boost 1.38.0 | Severity: Problem
 Keywords: uBlas, storage scheme, row_major, column_major, triangular_matrix, transposed_structure |
 The transposed_structure template simply takes an upper triangular matrix
 and regards it as the transpose of a lower triangular matrix. It doesn't
 take into account the row/column major storage, leading to the following

 If we take the upper matrix U

 1 2 3
 - 4 5
 - - 6

 and regard it as the transpose of a lower matrix L

 2 4
 3 5 6

 without a row/column major swap, then storing the row major version of the
 lower matrix is the same as storing the column major version of the upper

 a) row_major for U: 1 2 3 4 5 6
 b) row_major for L: 1 2 4 3 5 6

 Since the transposed_structure template simply maps the elements to the
 transpose and doesn't change the storage, we are in fact storing b)
 instead of a).

Ticket URL: <https://svn.boost.org/trac/boost/ticket/2800>
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