def _log_dirichlet_norm(dirichlet_concentration):
 return (gammaln(np.sum(dirichlet_concentration)) - np.sum(gammaln(dirichlet_concentration)))

def _log_dirichlet_norm ( dirichlet_concentration ) : return ( gammaln ( np . sum ( dirichlet_concentration ) ) - np . sum ( gammaln ( dirichlet_concentration ) ) )
compute the log of the dirichlet distribution normalization term .