Boost C++ Libraries: Ticket #2686: lower/upper triangular matrices are defined and used transposed from math usage https://svn.boost.org/trac10/ticket/2686 <p> The first paragraph of <a href="http://www.boost.org/doc/libs/1_37_0/libs/numeric/ublas/doc/triangular.htm#triangular_matrix">http://www.boost.org/doc/libs/1_37_0/libs/numeric/ublas/doc/triangular.htm#triangular_matrix</a> describes when elements of lower and upper triangular matrices are fixed at 0, The definition is transposed from what I have always understood to define lower/upper triangular. With the given definition, a lower triangular matrix has enforced zeros in the lower triangular portion (when i&gt;j). To me, that is an upper triangular matrix. Oh, I just looked at a little bit of the code and I think it does what the document says -- i.e., the wrong thing. So, this ticket should apply to numeric/ublas software also. </p> en-us Boost C++ Libraries /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/2686 Trac 1.4.3 Steven Watanabe Thu, 29 Jan 2009 19:19:02 GMT owner, component changed https://svn.boost.org/trac10/ticket/2686#comment:1 https://svn.boost.org/trac10/ticket/2686#comment:1 <ul> <li><strong>owner</strong> changed from <span class="trac-author">Matias Capeletto</span> to <span class="trac-author">Gunter</span> </li> <li><strong>component</strong> <span class="trac-field-old">Documentation</span> → <span class="trac-field-new">uBLAS</span> </li> </ul> Ticket Gunter Fri, 30 Jan 2009 21:12:35 GMT status changed; resolution set https://svn.boost.org/trac10/ticket/2686#comment:2 https://svn.boost.org/trac10/ticket/2686#comment:2 <ul> <li><strong>status</strong> <span class="trac-field-old">new</span> → <span class="trac-field-new">closed</span> </li> <li><strong>resolution</strong> → <span class="trac-field-new">fixed</span> </li> </ul> <p> (In <a class="changeset" href="https://svn.boost.org/trac10/changeset/50916" title="* fix and close #2686 * replaced the word &#34;upper&#34; by &#34;lower&#34; because ...">[50916]</a>) * fix and close <a class="closed ticket" href="https://svn.boost.org/trac10/ticket/2686" title="#2686: Bugs: lower/upper triangular matrices are defined and used transposed from ... (closed: fixed)">#2686</a> </p> <ul><li>replaced the word "upper" by "lower" because the description is for lower triangular matrices </li></ul><ul><li>added more detailed example for the use of triangular matrices and adaptors </li></ul> Ticket