class_docstr: Inherits time series methods from TSM class.
  
  **** GENERALIZED AUTOREGRESSIVE SCORE (GAS) REGRESSION MODELS ****
  
  Parameters
  ----------
  
  formula : string
      patsy string describing the regression
  
  data : pd.DataFrame or np.array
      Field to specify the data that will be used
  
  family : GAS family object
      Which distribution to use, e.g. GASNormal()
class_docstr_tok: ["Inherits","time","series","methods","from","TSM","class",".","*","*","*","*","GENERALIZED","AUTOREGRESSIVE","SCORE","(","GAS",")","REGRESSION","MODELS","*","*","*","*","Parameters","--","--","--","--","--","formula",":","string","patsy","string","describing","the","regression","data",":","pd.DataFrame","or","np.array","Field","to","specify","the","data","that","will","be","used","family",":","GAS","family","object","Which","distribution","to","use",",","e.g",".","GASNormal","(",")"]
docstr: Returns the negative loglikelihood of the model
  
  Parameters
  ----------
  beta : np.array
      Contains untransformed starting values for latent variables
docstr_tok: ["Returns","the","negative","loglikelihood","of","the","model","Parameters","--","--","--","--","--","beta",":","np.array","Contains","untransformed","starting","values","for","latent","variables"]
code: def neg_loglik(self, beta):
      """Returns the negative loglikelihood of the model
  
      Parameters
      ----------
      beta : np.array
          Contains untransformed starting values for latent variables
      """
      theta, Y, scores, _ = self._model(beta)
      parm = np.array(
          [
              self.latent_variables.z_list[k].prior.transform(beta[k])
              for k in range(beta.shape[0])
          ]
      )
      (
          model_scale,
          model_shape,
          model_skewness,
      ) = self._get_scale_and_shape(parm)
      return self.family.neg_loglikelihood(
          Y, self.link(theta), model_scale, model_shape, model_skewness
      )
  
imports: import sys
  import numpy
  import pandas
  import scipy.stats
  import scipy.special
  from patsy import dmatrices, dmatrix, demo_data
  from ..None import families
  from ..None import tsm
  from ..None import data_check
  from .gas_core_recursions import gas_reg_recursion
label_desc: Use image node_id 11 for calling the GASReg obj's underlying member method code with example usage: obj.neg_loglik(beta) and returns: self