title: Converting 2D cell of 2D matrices (consistent sizes) into 4D matlab double
body: <p>Searching around here one finds many questions how one can convert cell arrays of doubles into one big matrix.<br>
  In my application I have a two dimensional cell array (lets call it <code>celldata</code> of size <code>m</code> times <code>n</code>) of all same sized double matrices (lets say of size <code>a</code> times <code>b</code>).<br>
  I want to convert that data structure into one bit 4D double (<code>m</code> times <code>n</code> times <code>a</code> times <code>b</code>).<br>
  At the moment I do that by</p>
  
  <pre><code>reshape(cat(3,celldata{:}),m,n,a,b)
  </code></pre>
  
  <p>but maybe there are other methods doing that directly? Maybe with a call like</p>
  
  <pre><code>cat([3 4],celldata{:,:})
  </code></pre>
  
  <p>or similar.</p>