docstr: Method to treat and initialize the model. . Extends init_model from MatrixFactorization
docstr_tok: ["Method","to","treat","and","initialize","the","model",".",".","Extends","init_model","from","MatrixFactorization"]
code: def init_model(self):
      """
      Method to treat and initialize the model. . Extends init_model from MatrixFactorization
  
      """
  
      super(SVDPlusPlus, self).init_model()
  
      self.n_u = {}
      self.items_id_seen_by_user = {}
  
      for user in self.train_set["users"]:
          for item in self.train_set["items_seen_by_user"][user]:
              self.items_id_seen_by_user.setdefault(
                  self.user_to_user_id[user], []
              ).append(self.item_to_item_id[item])
          # |N(u)|^(-1/2)
          self.n_u[self.user_to_user_id[user]] = np.sqrt(
              len(self.train_set["items_seen_by_user"][user])
          )
  
file_path: CaseRecommender/caserec/recommenders/rating_prediction/svdplusplus.py
imports: import numpy
  from caserec.recommenders.rating_prediction.matrixfactorization import MatrixFactorization
label_desc: Use image node_id 2 for calling the SVDPlusPlus obj's underlying member method code with example usage: obj.init_model() without return types