title: rollapply applied to xts object
body: <pre><code>require(quantmod)
  require(PerformanceAnalytics)
  getSymbols('INTC')
  x&lt;- monthlyReturn(INTC)
  rollapply(1+x,12,cumprod)
  </code></pre>
  
  <p>Given the code above, I got this error</p>
  
  <pre><code>Error in array(r, dim = d, dimnames = if (!(is.null(n1 &lt;- names(x[[1L]])) &amp;  : 
    length of 'dimnames' [1] not equal to array extent
  </code></pre>
  
  <p>I can verify that the class of x is indeed xts.</p>
  
  <blockquote>
    <p>class(x)
        [1] "xts" "zoo"</p>
  </blockquote>
  
  <p>I suppose rollapply works on xts/zoo object. I am not sure how to resolve the issue here.</p>
  
  <p>Thanks for the help.</p>
  
  <p><strong>Update</strong></p>
  
  <p>SessionInfo Output:</p>
  
  <pre><code>R version 2.15.3 (2013-03-01)
  Platform: i686-pc-linux-gnu (32-bit)
  
  locale:
   [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C               LC_TIME=en_US.UTF-8       
   [4] LC_COLLATE=en_US.UTF-8     LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8   
   [7] LC_PAPER=C                 LC_NAME=C                  LC_ADDRESS=C              
  [10] LC_TELEPHONE=C             LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       
  
  attached base packages:
  [1] stats     graphics  grDevices utils     datasets  methods   base     
  
  other attached packages:
  [1] PerformanceAnalytics_1.1.0 quantmod_0.4-0             TTR_0.22-0                
  [4] xts_0.9-3                  zoo_1.7-9                  Defaults_1.1-1            
  
  loaded via a namespace (and not attached):
  [1] grid_2.15.3     lattice_0.20-13 tools_2.15.3   
  </code></pre>