title: get upper triangle of eigen::selfadjointView<Lower>()
body: <p>I have this which works fine:</p>
  
  <pre><code>MatrixXf Sig(p,p);
  Sig.selfadjointView&lt;Lower&gt;().rankUpdate(xSub.adjoint());
  </code></pre>
  
  <p>Now, i need to also get the upper triangular 
  part of <code>Sig</code>. <a href="http://forum.kde.org/viewtopic.php?f=74&amp;t=109729&amp;sid=b7152c9f2bb0531d3b568275e856aa6b" rel="nofollow">This</a> answer seems to suggest 
  to do </p>
  
  <pre><code>Sig.triangularView&lt;StrictUpper&gt;()=Sig.adjoint().triangularView&lt;StrictUpper&gt;(); 
  </code></pre>
  
  <p>But doing that causes mayhem --or as the compiler calls it:</p>
  
  <pre><code>DetMCD_1.cpp: In function ‘float CStep(const MatrixXf&amp;, Eigen::VectorXi&amp;, const int&amp;, const int&amp;)’:
  DetMCD_1.cpp:263:21: error: ‘StrictUpper’ was not declared in this scope
  DetMCD_1.cpp:263:34: error: no matching function for call to ‘Eigen::Matrix&lt;float, -0x00000000000000001, -0x00000000000000001&gt;::triangularView()’
  DetMCD_1.cpp:263:34: note: candidates are:
  /home/kaveh/R/x86_64-pc-linux-gnu-library/2.15/RcppEigen/include/Eigen/src/Core/MatrixBase.h:248:79: note: template&lt;unsigned int Mode&gt; typename Eigen::MatrixBase&lt;Derived&gt;::TriangularViewReturnType&lt;Mode&gt;::Type Eigen::MatrixBase::triangularView() [with unsigned int Mode = Mode, Derived = Eigen::Matrix&lt;float, -0x00000000000000001, -0x00000000000000001&gt;, typename Eigen::MatrixBase&lt;Derived&gt;::TriangularViewReturnType&lt;Mode&gt;::Type = &lt;type error&gt;]
  /home/kaveh/R/x86_64-pc-linux-gnu-library/2.15/RcppEigen/include/Eigen/src/Core/MatrixBase.h:249:84: note: template&lt;unsigned int Mode&gt; typename Eigen::MatrixBase&lt;Derived&gt;::ConstTriangularViewReturnType&lt;Mode&gt;::Type Eigen::MatrixBase::triangularView() const [with unsigned int Mode = Mode, Derived = Eigen::Matrix&lt;float, -0x00000000000000001, -0x00000000000000001&gt;, typename Eigen::MatrixBase&lt;Derived&gt;::ConstTriangularViewReturnType&lt;Mode&gt;::Type = &lt;type error&gt;]
  DetMCD_1.cpp:263:78: error: no matching function for call to ‘Eigen::Transpose&lt;const Eigen::Matrix&lt;float, -0x00000000000000001, -0x00000000000000001&gt; &gt;::triangularView() const’
  DetMCD_1.cpp:263:78: note: candidates are:
  /home/kaveh/R/x86_64-pc-linux-gnu-library/2.15/RcppEigen/include/Eigen/src/Core/MatrixBase.h:248:79: note: template&lt;unsigned int Mode&gt; typename Eigen::MatrixBase&lt;Derived&gt;::TriangularViewReturnType&lt;Mode&gt;::Type Eigen::MatrixBase::triangularView() [with unsigned int Mode = Mode, Derived = Eigen::Transpose&lt;const Eigen::Matrix&lt;float, -0x00000000000000001, -0x00000000000000001&gt; &gt;, typename Eigen::MatrixBase&lt;Derived&gt;::TriangularViewReturnType&lt;Mode&gt;::Type = &lt;type error&gt;]
  /home/kaveh/R/x86_64-pc-linux-gnu-library/2.15/RcppEigen/include/Eigen/src/Core/MatrixBase.h:249:84: note: template&lt;unsigned int Mode&gt; typename Eigen::MatrixBase&lt;Derived&gt;::ConstTriangularViewReturnType&lt;Mode&gt;::Type Eigen::MatrixBase::triangularView() const [with unsigned int Mode = Mode, Derived = Eigen::Transpose&lt;const Eigen::Matrix&lt;float, -0x00000000000000001, -0x00000000000000001&gt; &gt;, typename Eigen::MatrixBase&lt;Derived&gt;::ConstTriangularViewReturnType&lt;Mode&gt;::Type = &lt;type error&gt;]
  make: *** [DetMCD_1.o] Error 1
  </code></pre>
  
  <p>My question is this: given that i have 
  the lower triangular part of <code>Sig</code>, how 
  to convince eigen to return me the full 
  matrix?</p>