"Nick Cox" <[email protected]> writes:
> Jakob Petersen writes:
>
>> I would like to cluster a fairly large number of observation based on
>> presence of cases for a number of variables. Hierarchical clustering
>> with e.g. jaccard's similarity would be possible for a relatively
>> small data set due to the size of the similarity matrix (n x n). Is it
>> possible to use stata's cluster function with similarity matrices in a
>> long rather than wide format?
>
> I don't understand this. Seemingly no one else
> does either.
>
> Similarity matrices are square. So, there is no
> choice between wide and long, and no possibility
> of them being oblong (rectangular, if you wish,
> but a square is a rectangle too).
>
> Very likely I am misunderstanding what you want.
I presume the original poster means by long a vector representation
of the similarity matrix. For instance, in Mata, if S is a
similarity matrix, vech(S) is a column-wise vector representation
of its lower triangle.
If the similarity data arrives in such a format, you can create the
square matrix in mata using invvech().
Brendan
--
Brendan Halpin, Department of Sociology, University of Limerick, Ireland
Tel: w +353-61-213147 f +353-61-202569 h +353-61-338562; Room F2-025 x 3147
mailto:[email protected] http://www.ul.ie/sociology/brendan.halpin.html
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