Corrected expected values for 'no-slycot' condition in newly-added unit tests

josiahdelange · josiahdelange · commit 397efabbe7ff · 2025-04-26T14:49:32.000-04:00
diff --git a/control/tests/margin_test.py b/control/tests/margin_test.py
@@ -403,17 +403,35 @@ def test_mimo_disk_margin():
     Lo = P*K # loop transfer function, broken at plant output
     Li = K*P # loop transfer function, broken at plant input
 
-    # Balanced (S - T) disk-based stability margins at plant output
-    DMo, DGMo, DPMo = disk_margins(Lo, omega, skew = 0.0)
-    assert_allclose([DMo], [0.3754], atol = 0.1) # disk margin of 0.3754
-    assert_allclose([DGMo], [3.3], atol = 0.1) # disk-based gain margin of 3.3 dB 
-    assert_allclose([DPMo], [21.26], atol = 0.1) # disk-based phase margin of 21.26 deg
-
-    # Balanced (S - T) disk-based stability margins at plant input
-    DMi, DGMi, DPMi = disk_margins(Li, omega, skew = 0.0)
-    assert_allclose([DMi], [0.3754], atol = 0.1) # disk margin of 0.3754
-    assert_allclose([DGMi], [3.3], atol = 0.1) # disk-based gain margin of 3.3 dB 
-    assert_allclose([DPMi], [21.26], atol = 0.1) # disk-based phase margin of 21.26 deg
+    try:
+        import slycot
+    except ImportError:
+        with pytest.raises(ControlMIMONotImplemented,\
+            match = "Need slycot to compute MIMO disk_margins"):
+
+            # Balanced (S - T) disk-based stability margins at plant output
+            DMo, DGMo, DPMo = disk_margins(Lo, omega, skew = 0.0)
+            assert_allclose([DMo], [0.3754], atol = 0.1) # disk margin of 0.3754
+            assert_allclose([DGMo], [3.3], atol = 0.1) # disk-based gain margin of 3.3 dB 
+            assert_allclose([DPMo], [21.26], atol = 0.1) # disk-based phase margin of 21.26 deg
+
+            # Balanced (S - T) disk-based stability margins at plant input
+            DMi, DGMi, DPMi = disk_margins(Li, omega, skew = 0.0)
+            assert_allclose([DMi], [0.3754], atol = 0.1) # disk margin of 0.3754
+            assert_allclose([DGMi], [3.3], atol = 0.1) # disk-based gain margin of 3.3 dB 
+            assert_allclose([DPMi], [21.26], atol = 0.1) # disk-based phase margin of 21.26 deg
+    else:
+        # Balanced (S - T) disk-based stability margins at plant output
+        DMo, DGMo, DPMo = disk_margins(Lo, omega, skew = 0.0)
+        assert_allclose([DMo], [0.3754], atol = 0.1) # disk margin of 0.3754
+        assert_allclose([DGMo], [3.3], atol = 0.1) # disk-based gain margin of 3.3 dB 
+        assert_allclose([DPMo], [21.26], atol = 0.1) # disk-based phase margin of 21.26 deg
+
+        # Balanced (S - T) disk-based stability margins at plant input
+        DMi, DGMi, DPMi = disk_margins(Li, omega, skew = 0.0)
+        assert_allclose([DMi], [0.3754], atol = 0.1) # disk margin of 0.3754
+        assert_allclose([DGMi], [3.3], atol = 0.1) # disk-based gain margin of 3.3 dB 
+        assert_allclose([DPMi], [21.26], atol = 0.1) # disk-based phase margin of 21.26 deg
 
 def test_siso_disk_margin_return_all():
     # Frequencies of interest
@@ -443,24 +461,50 @@ def test_mimo_disk_margin_return_all():
     Lo = P*K # loop transfer function, broken at plant output
     Li = K*P # loop transfer function, broken at plant input
 
-    # Balanced (S - T) disk-based stability margins at plant output
-    DMo, DGMo, DPMo = disk_margins(Lo, omega, skew = 0.0, returnall = True)
-    assert_allclose([omega[np.argmin(DMo)]], [omega[0]],\
-        atol = 0.01) # sensitivity peak at 0 rad/s (or smallest provided)
-    assert_allclose([min(DMo)], [0.3754], atol = 0.1) # disk margin of 0.3754
-    assert_allclose([DGMo[np.argmin(DMo)]], [3.3],\
-        atol = 0.1) # disk-based gain margin of 3.3 dB 
-    assert_allclose([DPMo[np.argmin(DMo)]], [21.26],\
-        atol = 0.1) # disk-based phase margin of 21.26 deg
-
-    # Balanced (S - T) disk-based stability margins at plant input
-    DMi, DGMi, DPMi = disk_margins(Li, omega, skew = 0.0, returnall = True)
-    assert_allclose([omega[np.argmin(DMi)]], [omega[0]],\
-        atol = 0.01) # sensitivity peak at 0 rad/s (or smallest provided)
-    assert_allclose([min(DMi)], [0.3754],\
-        atol = 0.1) # disk margin of 0.3754
-    assert_allclose([DGMi[np.argmin(DMi)]], [3.3],\
-        atol = 0.1) # disk-based gain margin of 3.3 dB 
-    assert_allclose([DPMi[np.argmin(DMi)]], [21.26],\
-        atol = 0.1) # disk-based phase margin of 21.26 deg
-
+    try:
+        import slycot
+    except ImportError:
+        with pytest.raises(ControlMIMONotImplemented,\
+            match = "Need slycot to compute MIMO disk_margins"):
+
+            # Balanced (S - T) disk-based stability margins at plant output
+            DMo, DGMo, DPMo = disk_margins(Lo, omega, skew = 0.0, returnall = True)
+            assert_allclose([omega[np.argmin(DMo)]], [omega[0]],\
+                atol = 0.01) # sensitivity peak at 0 rad/s (or smallest provided)
+            assert_allclose([min(DMo)], [0.3754], atol = 0.1) # disk margin of 0.3754
+            assert_allclose([DGMo[np.argmin(DMo)]], [3.3],\
+                atol = 0.1) # disk-based gain margin of 3.3 dB 
+            assert_allclose([DPMo[np.argmin(DMo)]], [21.26],\
+                atol = 0.1) # disk-based phase margin of 21.26 deg
+
+            # Balanced (S - T) disk-based stability margins at plant input
+            DMi, DGMi, DPMi = disk_margins(Li, omega, skew = 0.0, returnall = True)
+            assert_allclose([omega[np.argmin(DMi)]], [omega[0]],\
+                atol = 0.01) # sensitivity peak at 0 rad/s (or smallest provided)
+            assert_allclose([min(DMi)], [0.3754],\
+                atol = 0.1) # disk margin of 0.3754
+            assert_allclose([DGMi[np.argmin(DMi)]], [3.3],\
+                atol = 0.1) # disk-based gain margin of 3.3 dB 
+            assert_allclose([DPMi[np.argmin(DMi)]], [21.26],\
+                atol = 0.1) # disk-based phase margin of 21.26 deg
+    else:
+        # Balanced (S - T) disk-based stability margins at plant output
+        DMo, DGMo, DPMo = disk_margins(Lo, omega, skew = 0.0, returnall = True)
+        assert_allclose([omega[np.argmin(DMo)]], [omega[0]],\
+            atol = 0.01) # sensitivity peak at 0 rad/s (or smallest provided)
+        assert_allclose([min(DMo)], [0.3754], atol = 0.1) # disk margin of 0.3754
+        assert_allclose([DGMo[np.argmin(DMo)]], [3.3],\
+            atol = 0.1) # disk-based gain margin of 3.3 dB 
+        assert_allclose([DPMo[np.argmin(DMo)]], [21.26],\
+            atol = 0.1) # disk-based phase margin of 21.26 deg
+
+        # Balanced (S - T) disk-based stability margins at plant input
+        DMi, DGMi, DPMi = disk_margins(Li, omega, skew = 0.0, returnall = True)
+        assert_allclose([omega[np.argmin(DMi)]], [omega[0]],\
+            atol = 0.01) # sensitivity peak at 0 rad/s (or smallest provided)
+        assert_allclose([min(DMi)], [0.3754],\
+            atol = 0.1) # disk margin of 0.3754
+        assert_allclose([DGMi[np.argmin(DMi)]], [3.3],\
+            atol = 0.1) # disk-based gain margin of 3.3 dB 
+        assert_allclose([DPMi[np.argmin(DMi)]], [21.26],\
+            atol = 0.1) # disk-based phase margin of 21.26 deg
