title: vector of indices
body: <p>I have a 10x10 matrix called A:</p>
  
  <p>I have vector of column numbers:</p>
  
  <p>C = [ 2, 6, 8 ];</p>
  
  <p>I have a vector of row numbers:</p>
  
  <p>R = [1; 3; 7];</p>
  
  <p>The column numbers correspond to each row. i.e. For column 1 we are looking at row numbers given by R, for column 3 we are looking at row numbers given by R and so on.</p>
  
  <p>I want to replace those exact locations in A with some other number 13.</p>
  
  <p>i.e. for each of these locations in matrix A:</p>
  
  <pre><code>(1,2) (1,6) (1,8), (3,2), (3, 6), (3,8) I want to insert 13.
  </code></pre>
  
  <p>How do I achieve the above ?</p>