title: col() in R gives warning message
body: <p>on 6-month-old iMac with OSX v. 10.8.5 using R v 2.15.2 (2012-10-26) with either RStudio or Terminal this simple code:   </p>
  
  <p><code>m &lt;- matrix(c(1,2,3,4),2)</code>  </p>
  
  <p>yields the expected 2x2 matrix and <code>row(m)</code> yields the expected 2x2 matrix with row 1s in the first row and 2s in the second.    </p>
  
  <p>But <code>col(m)</code> gave the following error:<br>
  <code>Warning message:  In seq. int(0, 1, length.out = n): first element used of 'length.out' argument.</code></p>
  
  <p>Curiously, the same code on a 5-year-old MacBook Air, OSX 10.6.8, but the same version of R gave the expected result for <code>col(m)</code> of 1's in the first col and 2s in the second.</p>
  
  <p>Any suggestions?</p>