topic model

[honnow]

hi,I used the search topic function in KH Coder software and selected the parameter ‘ldatuning’, resulting in the following results as shown in the figure. I don’t know what it means.

please explain, thank you

[ko-ichi-h]

This page may help:
https://rpubs.com/siri/ldatuning

[honnow]

i get it.thank you.

[honnow]

Also,about perplexity,as shown in the figure below.How to analyze the optimal number of topics.Please teach me.

[ko-ichi-h]

To decide on a suitable number of topics, you can compare the goodness-of-fit of LDA models fit with varying numbers of topics. You can evaluate the goodness-of-fit of an LDA model by calculating the perplexity of a held-out set of documents. The perplexity indicates how well the model describes a set of documents. A lower perplexity suggests a better fit.

https://de.mathworks.com/help/textanalytics/ug/choose-number-of-topics-for-LDA-model.html

[honnow]

thank you

[honnow]

and how to select the parameter,for example,(seq(2, 35, by=3), 40, 45, 50, 60)，what do these numbers mean。

[ko-ichi-h]

seq(2, 35, by=3) means 2, 5, 8, 11,,, 35.

2: start
35: end
by=3: step

40, 50, 60 means 40, 50, 60

We calculate perplexity for topic number 2, 5, 8, 11,,, 35, 40, 50, and 60.

[honnow]

thank you .