Add requirements in setup.py, typing, and some more tests.

setup.py

@@ -11,9 +11,9 @@ def read(fname):
 
 setuptools.setup(
     name="yulewalker",
-    version="0.1",
+    version="0.1.1",
     author="Emmanouil Theofanis Chourdakis",
-    author_email="eruyome@gmail.com",
+    author_email="emmanouil.chourdakis@nomono.co",
     description="IIR Filter design using the modified Yule-Walker method",
     classifiers=[
         "Topic :: Scientific/Engineering",
@@ -24,4 +24,8 @@ def read(fname):
     long_description=read("README.md"),
     license="CeCILL-2.1",
     keywords="yulewalk yulewalker iir signal-processing dsp",
+    install_requires=[
+        "numpy>=1.19.2",
+        "scipy>=1.5.2",
+    ],
 )

yulewalker/yulewalker.py

@@ -57,9 +57,15 @@ def interpolate_freq_mag(
     return new_freq, new_mag
 
 
-def polystab(p):
+def polystab(p: np.ndarray) -> np.ndarray:
     """
     Reflects the roots of polynomial `p` that are outside the unit circle back inside.
+
+    >>> polystab(np.array([[1.,2.,1.]]))
+    array([1., 2., 1.])
+
+    >>> polystab(np.array([[1.,2.,1.01]]))
+    array([1.        , 1.98019802, 0.99009901])
     """
     if p.ndim == 2 and (p.shape[0] == 1 or p.shape[1] == 1):
         p = p.flatten()
@@ -76,7 +82,9 @@ def polystab(p):
     return b
 
 
-def numf(impulse_response, denominator, numerator_order):
+def numf(
+    impulse_response: np.ndarray, denominator: np.ndarray, numerator_order: int
+) -> np.ndarray:
     """
     Find the numberator of the impulse response `impulse_response` of a frequency
     response H = numerator/denominator.
@@ -93,7 +101,9 @@ def numf(impulse_response, denominator, numerator_order):
     return b
 
 
-def yulewalk(filter_order, frequencies, magnitudes, npt=512):
+def yulewalk(
+    filter_order: int, frequencies: np.ndarray, magnitudes: np.ndarray, npt: int = 512
+) -> Tuple[np.ndarray, np.ndarray]:
     """
     Recursive filter-design of an arbritrary frequency response using the
     modified Yule-Walker method [1].