Hi all,

I would like to seek help if someone has experience in estimating the K in LDA? I watch David Blei video on videolectures.net as he mentioned that it is achievable but was not described in the PPT or video. I google around and found that Hierachical LDA is one of doing it but not much code was found, can anyone provide some more detail information, thanks.

Regards, Andy.

asked Jan 06 at 11:11

cherhan's gravatar image

cherhan
190121518


3 Answers:

I think Indian Buffet Processes do what you want, see cocosci.berkeley.edu/tom/papers/ibptr.pdf.

answered Jan 07 at 12:15

Daniel%20Mahler's gravatar image

Daniel Mahler
8462912

edited Jan 07 at 12:18

Not really, the correct nonparametric extension to LDA is given by the Hierarchical Dirichlet Process. For a practical algorithm see http://www.cs.princeton.edu/~chongw/papers/WangPaisleyBlei2011.pdf

(Jan 07 at 12:16) Alexandre Passos ♦

Aside from nonparametric methods, if you can estimate the held-out likelihood after fitting your model you can search for the value of k which maximizes this held-out likelihood. For computing that likelihood see, for example, Wallach et al Evaluation methods for topic models.

answered Jan 06 at 13:59

Alexandre%20Passos's gravatar image

Alexandre Passos ♦
1899744214335

K is the number of topics, right? Non-parametric methods are typically used for this. Look at the hierarchical Dirichlet process and extensions there of.

answered Jan 06 at 11:58

Noel%20Welsh's gravatar image

Noel Welsh
6263820

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