[R] Clustering

David Winsemius dwinsemius at comcast.net
Fri Oct 29 16:42:48 CEST 2010

On Oct 29, 2010, at 5:14 AM, dpender wrote:

> That's helpful but the reason I'm using clusters in evd is that I  
> need to
> specify a time condition to ensure independence.

I believe this is the first we heard about any particular function or  

> I therefore have an output

We would need to know the code that produced that output and either  
the data to which that code was applied or the structure of the  
output. (Use the str() function)

> in the form Cluster[[i]][j-k]  where i is the
> cluster number and j-k is the range of values above the threshold  
> taking
> account of the time condition.

Unless you find someone who uses that package in the manner you have,  
you will need to explain in much greater detail than you have so far.

>> From this I can get durations easily enough but the spacing is  
>> proving quite
> difficult.

There are quite possibly methods using rle() or possibly something  
like rollapply() from the zoo package, but you need to provide a  
specific and richer test case.

> The data is for ocean waves and therefore it may be possible that  
> the wave
> height drops below the threshold for a short period but should still  
> be
> considered part of the same event, hence the time conditon.
> Hope this clarifies the problem.

It clarifies it to the extent that it show how much more you will need  
to further clarify.


David Winsemius, MD
West Hartford, CT

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