Hyperparameters of LDA

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  MartinLiebig Administrator, Moderator, Employee, RapidMiner Certified Analyst, RapidMiner Certified Expert, University Professor Posts: 3,507 RM Data Scientist

  December 2018 Solution Accepted

  Hey,
  Neither Alpha nor Beta are "performance" metrics of your model (even though I've added it to the performance output).
  
  Alpha or Beta are parameters of the model. It basically tells you how much either a word is allowed to be associated with more than one topic or one document is allowed to be associated with one topic. 
  By default, RapidMiner uses heuristics to set it (see documentation of the operators). Further, the algorithm is automatically tuning the hyperparameters internally (you can deactivate this). I think what you see is one of these two effects. You cannot judge on the setting of the number of topics nor on the alpha/beta settings. To do this you would need to check the other performance metrics for different topics (maybe with different alpha/beta or auto-tuning options).
  
  BR,
  Martin
  
  
  

  - Sr. Director Data Solutions, Altair RapidMiner -
  Dortmund, Germany

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