On Tue, 12 Oct 2004, Martin Maechler wrote: >>>>>> "Dan" == Dan Bolser <[EMAIL PROTECTED]> >>>>>> on Mon, 11 Oct 2004 16:21:53 +0100 (BST) writes: > > Dan> Gives strange results. > > Dan> I get 'weird' dendrograms with canberra / binary distance metric and > Dan> median / centroid cluster methods. > >it doesn't depend on the metric: >Both 'median' and 'centroid' methods are known to *not* >guarantee ``monotone distance measures'', or equivalently to >possibly lead to dendrograms with so called ``inversions''. >We should add this to help page for hclust().
Cool, I could do with more to read about these methods. It might be worth noteing that no bootstrap exists for the method (implemented in R that is). How can I quickly run a test on a sub-set of x? (i.e. quick bootstrap by hand)? Cheers, Dan. >Probably for this reason, agnes() from the cluster package >doesn't have these two methods [explicitly] -- though it now >allows general parameter Lance-William formula methods which can >also lead to inversions. > > Dan> Is this just my data? > >evidently not. Though the problem does not appear for all data >sets... > >Regards, >Martin Maechler > ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
