title: Cell containing 2-D varying dimension matrices
body: <p>I have a big 2D matrix of, say, 1000 by 10. I am trying to split that matrix into multiple 2D matrices. They can be 10 by 10, 5 by 10 or 23 by 10. The column size does not change and I am splitting them based on the number in the first column. (In my true case, I do it for the first two columns.) In other words, I'm putting the rows with same id tag, which is the first column value of the vector.</p>
  
  <p>I am trying to achieve this through for loop. And I think it is best to put them into a 'cell array' because cell array allows user to have data in different dimension and different types. So, I want a cell (1-by-varying-N?) where N is the number of matrices split and there are N 2D matrices of varying sizes.</p>
  
  <p>Here my questions are</p>
  
  <ol>
  <li><p>In this case, should I think the cell as 3-dimension?</p></li>
  <li><p>How can I initialize a cell with varying dimension?</p></li>
  <li><p>Given that I have 2D matrix in n-by-m, how can I insert the matrix into a cell?</p></li>
  </ol>
  
  <p>There are not very many references with varying cell dimension. Any tip / answer would be really appreciated.</p>