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Re: st: clustering sequences - problem with cluster and clustermat


From   Nick Cox <[email protected]>
To   "[email protected]" <[email protected]>
Subject   Re: st: clustering sequences - problem with cluster and clustermat
Date   Tue, 16 Apr 2013 11:05:25 +0100

I don't know what your first sentence means.

But my guess is that there isn't enough memory for one of the programs
called by -cluster- to create a matrix.

Precisely what the memory limit is clearly of interest to you, but I
can't see that it's your main problem. Your main problem is, I
suggest, making your goal here clearer to yourself.

2700 observations is a _big_ classification problem, particularly when
you consider that the number of comparisons goes up with the square of
the number of objects.

Even more crucially, clustering a single variable, which you are
trying to do, can't show much -- arguably, can't show anything --
that's not evident by looking for clusters on a distribution display.
With 2700 observations, a histogram might be too coarse and you will
get better detail from a quantile plot or a dot plot; but what's
crucial is how many distinct values there are, not the number of
observations.

If there are gaps, and thus clusters, they will be obvious on a
sufficiently detailed graph. Otherwise your variable is a continuum.

I can't improve on what is said here by Stata user Phil Ender

http://www.philender.com/courses/multivariate/notes2/cluster0.html

Nick
[email protected]

On 16 April 2013 10:36, BUSSI, Margherita <[email protected]> wrote:

> I've done a sequence analysis based with subcost based on the means of transitions between states.
> I've got a new variable that it not a dissimilarity matrix (as I wrongly? expected)
> I tried to operate a cluster analysis but I got this message:
>
> Cluster medianlinkage meanprob
> cluster name: _clus_1
> insufficient memory for  ClusterMatrix
>
> What memory is stata talking about? Storing? Running memory? And why Clustermatrix if when I give the command "clustermat" it does not find the matrix?
>
> if I ask
> . cluster  singlelinkage meanprob
> It runs forever...
> (I've 3700 observations)
>
> Does anyone have an idea how to solve it or where is my mistake?
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