title: Create a bigger matrix from smaller one
body: <p>I have a matrix A which is:</p>
  
  <pre><code>A &lt;- matrix(c(1:15), byrow=T, nrow=5)
  A
       [,1] [,2] [,3]
  [1,]    1    2    3
  [2,]    4    5    6
  [3,]    7    8    9
  [4,]   10   11   12
  [5,]   13   14   15
  </code></pre>
  
  <p>Now I want to create a matrix B, which is 8x8 dimensions (or 10x10, or 15x15, etc), which would look like this:</p>
  
  <pre><code>     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8]
  [1,]    1    2    3    0    0    0    0    0
  [2,]    4    5    6    0    0    0    0    0
  [3,]    7    8    9    0    0    0    0    0
  [4,]   10   11   12    0    0    0    0    0
  [5,]   13   14   15    0    0    0    0    0
  [6,]    0    0    0    0    0    0    0    0
  [7,]    0    0    0    0    0    0    0    0
  [8,]    0    0    0    0    0    0    0    0
  </code></pre>
  
  <p>So starting from A, I want to add columns and rows, to an 8x8 dimensions, all replaced with zero values...
  Any idea? 
  Thank you in advance!!</p>