Ward's method as initially implemented by Ward generally does not produce 
the best hierarchical solutions.  Unless your data are of a naturally 
hierarchical nature, I would suggest looked at some other method.  You may 
wish to check the website for "CLUSTAN" package of programs; also obtain an 
old CLUSTAN manual which would explain in some detail the operation of many 
distance measures as well as a good variety of clustering methods.

Leo Horseman

>From: "Kejun (Kevin) Mei" <[log in to unmask]>
>Reply-To: "Classification, clustering, and phylogeny estimation"            
>   <[log in to unmask]>
>To: [log in to unmask]
>Subject: clustering with distance matrix as input
>Date: Fri, 15 Sep 2006 15:17:57 -0500
>
>Can someone please tell me a clustering method that use
>a distance matrix as input? I tried implementing the Ward
>method, but found the final clusters are not so good in my
>application, when I trace how clusters are grouped and
>how cluster centers are updated. I am seeking an improved
>version of the Ward method, or any others.
>
>Thank you so much and have a great weekend.
>
>-Kevin
>
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