#!/usr/bin/python

# 10.4

import scipy as sp

from imcsplit import imcsplit

def imc_stable1(B, A, k, alpha):

    """ Designs Discrete Internal Model Controller

    for transfer function z^{-k}B(z^{-1})/A(z^{-1})

    Numerator and Denominator of IMC HQ are outputs

    Controller is also given in R,S form. """

    Kp, d, Bg, Bnmp, Bm = imcsplit(B, 1)

    Bg = Kp * Bg

    Bnmpr = Bnmp[::]

    Bms = sum(Bm)

    HiN = A

    HiD = Bms * sp.convolve(Bg, Bnmpr)

    k = k+d

    return k, HiN, HiD