set array_priority=11 for TransferFunction, to match StateSpace

murrayrm · murrayrm · commit 8793d780a0ed · 2021-01-07T21:47:16.000-08:00
diff --git a/control/tests/xferfcn_test.py b/control/tests/xferfcn_test.py
@@ -5,7 +5,9 @@
 
 import numpy as np
 import pytest
+import operator
 
+import control as ct
 from control.statesp import StateSpace, _convertToStateSpace, rss
 from control.xferfcn import TransferFunction, _convert_to_transfer_function, \
     ss2tf
@@ -1022,3 +1024,20 @@ def test_returnScipySignalLTI_error(self, mimotf):
             mimotf.returnScipySignalLTI()
         with pytest.raises(ValueError):
             mimotf.returnScipySignalLTI(strict=True)
+
+@pytest.mark.parametrize(
+    "op",
+    [pytest.param(getattr(operator, s), id=s) for s in ('add', 'sub', 'mul')])
+@pytest.mark.parametrize(
+    "tf, arr",
+    [# pytest.param(ct.tf([1], [0.5, 1]), np.array(2.), id="0D scalar"),
+     # pytest.param(ct.tf([1], [0.5, 1]), np.array([2.]), id="1D scalar"),
+     pytest.param(ct.tf([1], [0.5, 1]), np.array([[2.]]), id="2D scalar")])
+def test_xferfcn_ndarray_precedence(op, tf, arr):
+    # Apply the operator to the transfer function and array
+    result = op(tf, arr)
+    assert isinstance(result, ct.TransferFunction)
+
+    # Apply the operator to the array and transfer function
+    result = op(arr, tf)
+    assert isinstance(result, ct.TransferFunction)
diff --git a/control/xferfcn.py b/control/xferfcn.py
@@ -114,6 +114,9 @@ class TransferFunction(LTI):
     >>> G  = (s + 1)/(s**2 + 2*s + 1)
     """
 
+    # Give TransferFunction._rmul_() priority for ndarray * TransferFunction
+    __array_priority__ = 11     # override ndarray and matrix types
+
     def __init__(self, *args, **kwargs):
         """TransferFunction(num, den[, dt])
 
