title: Get the row and column name of the minimum element of a matrix
body: <p>I need to get the row and column name of the smallest element of a matrix</p>
  
  <pre><code>&gt; mat = matrix(data=runif(12), nrow = 4, ncol=4)
  &gt; rownames(mat) = colnames(mat) = letters[1:4]
  &gt; 
  &gt; mat
    a         b         c         d
  a 0.3167865 0.6958895 0.4233572 0.3167865
  b 0.1042599 0.1552235 0.8461520 0.1552235
  c 0.6286461 0.9749868 0.2390978 0.6286461
  d 0.5923721 0.7823673 0.8427426 0.5923721
  &gt; min = min(mat)
  &gt; min
  &gt; 0.1042599
  </code></pre>
  
  <p>In this example I'd like to get "a" and "b"</p>