[R] Fwd: MDS problems [ajtee@ajtee.uklinux.net]

[Adam Tee]

On 03/26/04 14:07:30, Jari Oksanen wrote:
> The error message is clear: You have some identical sites so that
> theirdistance is zero. I think the canonical solution is to remove  
> the duplicate cases from the data before calculating the  
> dissimilarities. If your data frame is called X:
> 
> Xuniq <- unique(X)
> x.dist <- dist(Xuniq)
> 
> (or, as a one-liner: x.dist <- dist(unique(X))
>

One of the difficulties is that it is significant that some of the data  
is identical as I am comparing musical sequences. The above does not  
work as I am not dealing with the raw data. I am using my own  
dissimilarity measure output by a separate program.  The reason for  
using MDS is to visualise the data based on the developed dissimilarity  
measure.

Would it be better to use PCA ??



Adam