title: How to construct a matrix containing 9 smaller matrix
body: <p>I have nine matrices whose dimension as (N by N)
  <code>A1(i,j),A2(i,j),A3(i,j),A4(i,j),A5(i,j),A6(i,j),A7(i,j),A8(i,j),A9(i,j)</code></p>
  
  <p>Then I want to construct a larger matrix (3N by 3N) including these nine matrices as:</p>
  
  <pre><code>A = [A1 A2 A3
       A4 A5 A6
       A7 A8 A9]
  </code></pre>
  
  <p>In fortran, can I use the command line as</p>
  
  <pre><code>do i=1,FN
     do j=1,FML
        A(i,j) = [A1(i,j),A2(i,j),A3(i,j);A4(i,j),A5(i,j),A6(i,j);A7(i,j),A8(i,j),A9(i,j)]
     end do
  end do
  </code></pre>