Topic Models_ from reviews

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Hello Francisco,

I find your solution for topic number determination (Block 2) really interesting. Is there a more detailed explanation about how to perform this two-step perplexity method?

For me it is not clear how broad should be the range in the Step 2. In the meta-node description, it says the range of topics is [2,20] but the range in the resulting chart is [13, 17]. Thank you!