'stack lagpolynomial vertically in 2d array'

def vstack(self, a=None, name='ar'):

    if (not (a is None)):
        a = a
    elif (name == 'ar'):
        a = self.ar
    elif (name == 'ma'):
        a = self.ma
    else:
        raise ValueError('no    array    or    name    given')
    return a.reshape((-1), self.nvarall)
