[BioC] hcluster crashes R environment

[Henrique Proença]

Hello,

I am trying to apply the function "hcluster" (contained within the 
"amap" package) to data matrix with no variability between its columns. 
The example I am using is:


  x <- data.frame(col1=c(20,30,45,7,6,5,4,3),col2=c(20,30,45,7,6,5,4,3), 
stringsAsFactors=FALSE)
  hcluster(x, method="correlation", link = "complete")


In this case, the error generated is fatal and the application (R 
environment) stops completely (crashes) without any control of the 
error. I do understand it in the way one can not apply the correlation 
to a vector with no variability, but in the following case:

  x <- data.frame(col1=c(20,30,45,7,6,5,4,3),col2=c(20,30,45,7,6,5,7,7), 
stringsAsFactors=FALSE)
  hcluster(x, method="correlation", link = "complete")

There are rows without variability, and others (last two rows) 
containing some. When I use this example, the R environment does not 
crash. So, my question is: Why the "hcluster" funcions generates this 
fatal error when no variability is found in all the matrix rows ?


Thanks in advance

-- 
Regards
Henrique Proença