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

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From: Adam Tee (adam@ajtee.uklinux.net)
Date: Sat 27 Mar 2004 - 00:02:55 EST


Message-id: <20040326130255.GA9812@ajtee>

Hi all,

I'm trying to perform an MDS of some data that I have. When I use
cmdscale everything is fine and I get some interesting results however,
the tends to be low.

What I wnat to do is compare this with the Non-Metric MDS using isoMDS
or sammon. However, when I try using these I get the following message.

Error in isoMDS(x.dist) : zero or negative distance between objects 2
and 4

I am using as.dist to convert my full dissimilarity matrix.
Some of the dissimilarities, other than the diagonal, are zero which is
causing this, is there anything I can do to resolve this.

Below is a sample dissimilarity matrix

0 0 0.0694153 0.187033 0.193339
0 0 0.0146605 0.36829 0.563406
0.0694153 0.0146605 0 0.347965
0.187033 0.36829 0.347965 0

Thanks

Adam

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