[R] which function to use to do classification

Sean Davis
Wed, 29 Mar 2006 11:17:37 -0000

We have to be careful here.  Classification (which is the terminology that
the original poster used) is NOT the same as clustering, although the two
are often confused.  If the original poster wants to do clustering and
examine the results for the presence of three clusters, that is fine and
there are many methods for clustering that could be used.  However,
classification will require a different set of tools.  If the clustering
tools already pointed out are not doing what is needed (that is, that Cao
actually is interested in clustering and not classification), then perhaps a
further explanation of what the problem would help clarify.

Sean


On 3/29/06 1:46 AM, "Jacques VESLOT" <jacques.veslot at
cirad.fr> wrote:

> try this (suppose mat is your matrix):
>
> hc <- hclust(dist(mat,"manhattan"), "ward")
> plot(hc, hang=-1)
> (x <- identify(hc)) # rightclick to stop
> cutree(hc, 3)
>
> km<- kmeans(mat, 3)
> km$cluster
> km$centers
>
> pam(daisy(mat, metric = "manhattan"), k=3, diss=T)$clust
>
>
>
> Baoqiang Cao a ?crit :
>
>> Thanks!
>> I tried kmeans, the results is not very positive. Anyway, thanks
Jacques!
>> Please let me know if you have any other thoughts!
>>
>> Best regards,
>>    Baoqiang Cao
>>
>> ======= At 2006-03-29, 00:08:44 you wrote: ======>>
>>
>>
>>> if you want to classify rows or columns, read:
>>> ?hclust
>>> ?kmeans
>>> library(cluster)
>>> ?pam
>>>
>>>
>>> Baoqiang Cao a ?crit :
>>>
>>>
>>>
>>>> Dear All,
>>>>
>>>> I have a data, suppose it is an N*M matrix data. All I want is
to classify
>>>> it into, let see, 3 classes. Which method(s) do you think
is(are)
>>>> appropriate for this purpose? Any reference will be welcome!
Thanks!
>>>>
>>>> Best,
>>>> Baoqiang Cao
>>>>
>>>>
>>>>
>>>>
------------------------------------------------------------------------
>>>>
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>>>> http://www.R-project.org/posting-guide.html
>>>>
>>>>
>>>>
>>> .
>>>
>>>
>>
>> = = = = = = = = = = = = = = = = = = = >>
>> Baoqiang Cao
>> caobg at email.uc.edu
>> 2006-03-29
>>
>>
>>
>>
>
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