title: armadillo reshape from vector to cube
body: <p>I would like to take an <code>arma::vec</code> object and reshape it to an <code>arma::cube</code> object. </p>
  
  <p>For example:</p>
  
  <pre><code>vec param(mm*n*g);
  param.randn();
  cube LL = reshape(param,mm,n,g); // this line doesn't work
  </code></pre>
  
  <p>The easiest way I can get this to work is:</p>
  
  <pre><code>paramtemp = as&lt;NumericVector&gt;(wrap(param));
  cube LL(paramtemp.begin(),mm,n,g); 
  </code></pre>
  
  <p>But surely there is a more elegant way?</p>