statsmodels.tsa.varma_process.VarmaPoly.vstack# VarmaPoly.vstack(a=None, name='ar')[source]# Stack lagpolynomial vertically in 2d array Parameters: andarray, optionalLag polynomial array to stack. If None, uses self.ar or self.ma, selected by name. name{“ar”, “ma”}, optionalWhich instance lag polynomial to use when a is None. Returns: ndarrayThe lag polynomial stacked vertically into a 2d array.