Re: 3D test data that exhibits clustering?

And every attempt I tried so far to generate "random clusters" hasn't really worked either.

What exactly have you tried and why hasn't it worked?

The approach moritz suggests (or variations thereof) seems to be rather straightforward, and given the brilliance of mind you've often exhibited here, I cannot believe you haven't already thought of it... :) So, what's wrong with it?

Comment on Re: 3D test data that exhibits clustering?

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Re^2: 3D test data that exhibits clustering? by BrowserUk (Patriarch) on Jun 08, 2011 at 12:33 UTC
What exactly have you tried and why hasn't it worked? I tried generating random points around a set of random starting points, (without moritz' enhancement of a normal distribution around those starting points), but it generates sets like these. (Color coded for start point.) As you can see, you tend to either get very concentrated groupings very separate, or widely spread groups that almost entirely overlap. Neither is representative of the kind of plots you get from real datasets that exhibit clustering. moritz' enhancement might improve things somewhat--I'm trying it now--but if there were one or a few real datasets kicking around somewhere it would give me more confidence that I was performing a real test. Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice.	[reply]

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Re^2: 3D test data that exhibits clustering?
by BrowserUk (Patriarch) on Jun 08, 2011 at 12:33 UTC

What exactly have you tried and why hasn't it worked?

I tried generating random points around a set of random starting points, (without moritz' enhancement of a normal distribution around those starting points), but it generates sets like these. (Color coded for start point.)

As you can see, you tend to either get very concentrated groupings very separate, or widely spread groups that almost entirely overlap. Neither is representative of the kind of plots you get from real datasets that exhibit clustering.

moritz' enhancement might improve things somewhat--I'm trying it now--but if there were one or a few real datasets kicking around somewhere it would give me more confidence that I was performing a real test.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

[reply]