title: What is the best way to obtain the optimal number of topics for a LDA-Model using Gensim?
body: <p>I am trying to obtain the optimal number of topics for an LDA-model within Gensim. One method I found is to calculate the log likelihood for each model and compare each against each other, e.g. at <a href="https://stats.stackexchange.com/questions/25113/the-input-parameters-for-using-latent-dirichlet-allocation">The input parameters for using latent Dirichlet allocation</a></p>
  
  <p>Hence I looked into calculating the log likelihood of a LDA-model with Gensim and came across following post: <a href="https://stats.stackexchange.com/questions/126268/how-do-you-estimate-alpha-parameter-of-a-latent-dirichlet-allocation-model">How do you estimate α parameter of a latent dirichlet allocation model?</a></p>
  
  <p>which basically states that the update_alpha() method implements the method decribed in <em>Huang, Jonathan. Maximum likelihood estimation of Dirichlet distribution parameters</em>. Still I don't know how to obtain this parameter using the libary without changing the code.</p>
  
  <p>How can I obtain log likelihood from an LDA model with Gensim?</p>
  
  <p>Is there a better way to obtain optimal number of topics with Gensim?</p>