Using realizeNTF() function with a non-null STF parameter

[g-c-98]

When you try to call the "realizeNTF()" function while also passing an STF as a parameter, you get an IndexError:

Traceback (most recent call last):
File "...", line 563, in
struct = ds.realizeNTF(ntf, form, stf)
File "...", line 367, in realizeNTF
bi[i] = 1
IndexError: index 1 is out of bounds for axis 0 with size 1

Code for testing (any STF can be used, same error will appear):

import numpy as np
from scipy import signal as sp_sig
import deltasigma as ds

# "realizeNTF()" tests - with STF
order = 3
osr = 32
forms = np.array( ['CRFB', 'CRFF', 'CIFB', 'CIFF', 'CRFBD', 'CRFFD'] )
form = forms[0]

ntf = ds.synthesizeNTF(order, osr, 1)
print(f"ntf = ds.synthesizeNTF({order}, {osr}, 1) = \n", ntf), print()

#stf = sp_sig.tf2zpk(np.array([1.0, -3.0, 3.0, -1.0]), np.array([1.0, 0.0, 0.0, 0.0]))
stf = sp_sig.tf2zpk(np.array([1.0, -1.0]), np.array([1.0, 0.0]))
print(f"stf = \n", stf), print()

struct = ds.realizeNTF(ntf, form, stf)
print(f"struct = ds.realizeNTF(ntf, {form}, stf) = \n", struct), print()