title: R: heatmap.2 doesn't generate symmetrical plot even I set symm=T
body: <p>I have matrix with the same rownames and colnames:<a href="https://www.dropbox.com/s/c6ln0wojftno9hv/matrix?dl=0" rel="nofollow noreferrer">Matrix</a></p>
  
  <p>Then I use heatmap.2 to plot it symmetrically:</p>
  
  <pre><code>heatmap.2(matrix, Rowv=T, scale='none', dendrogram="row", symm =T, col = brewer.pal(9,"Reds"))
  </code></pre>
  
  <p>But I got the image as below:</p>
  
  <p><a href="https://i.stack.imgur.com/cS0Db.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cS0Db.png" alt="enter image description here"></a></p>
  
  <p>It is not symmetrical at all. Can someone give me a suggestion?</p>
  
  <p>Thanks,</p>
  
  <pre><code>sessionInfo()
  R version 3.3.1 (2016-06-21)
  Platform: x86_64-pc-linux-gnu (64-bit)
  Running under: Ubuntu 14.04.4 LTS
  
  locale:
   [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C               LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8    
   [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8    LC_PAPER=en_US.UTF-8       LC_NAME=C                 
   [9] LC_ADDRESS=C               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] RColorBrewer_1.1-2 gplots_3.0.1      
  
  loaded via a namespace (and not attached):
   [1] htmltools_0.3.5    tools_3.3.1        yaml_2.1.13        Rcpp_0.12.5        KernSmooth_2.23-15
   [6] rmarkdown_0.9.6    gdata_2.17.0       knitr_1.13         caTools_1.17.1     digest_0.6.9      
  [11] bitops_1.0-6       gtools_3.5.0      
  </code></pre>