title: matlab: error with subsref
body: <p>I am getting an error with:</p>
  
  <pre><code>b = cellfun(@(x) nansum(mag.*subsref(cross(u{1},x), struct('type', '()', 'subs', {':',':',3})) ),r,'UniformOutput',false);
  
  ??? Error using ==&gt; subsref
  The "subs" field for the subscript argument to SUBSREF and SUBSASGN must be a cell or character array.
  
  Error in ==&gt; cellcross&gt;@(x)nansum(mag.*subsref(cross(u{1},x),struct('type','()','subs',{':',':',3}))) at 2
      b = cellfun(@(x) nansum(mag.*subsref(cross(u{1},x), struct('type', '()', 'subs', {':',':',3})) ),r,'UniformOutput',false);
  
  Error in ==&gt; cellcross at 2
      b = cellfun(@(x) nansum(mag.*subsref(cross(u{1},x), struct('type', '()', 'subs', {':',':',3})) ),r,'UniformOutput',false); 
  </code></pre>
  
  <p>can anyone tell me why?</p>
  
  <p>I am using Matlab 2011.</p>