revert the removal of rtol for discrete margin test: conda on python3.6 is not as precise

bnavigator · bnavigator · commit 48a18d6218b9 · 2021-01-30T01:54:09.000+01:00
diff --git a/control/tests/margin_test.py b/control/tests/margin_test.py
@@ -336,19 +336,23 @@ def test_zmore_stability_margins(tsys_zmore):
 
 @pytest.mark.parametrize(
     'cnum, cden, dt,'
-    'ref,',
+    'ref,'
+    'rtol',
     [( # gh-465
       [2], [1, 3, 2, 0], 1e-2,  
-      (2.9558, 32.390, 0.43584, 1.4037, 0.74951, 0.97079)),
+      [2.9558, 32.390, 0.43584, 1.4037, 0.74951, 0.97079],
+      2e-3), # the gradient of the function reduces numerical precision
      ( # 2/(s+1)**3
       [2], [1, 3, 3, 1], .1,  
-      [3.4927, 65.4212, 0.5763, 1.6283, 0.76625, 1.2019]),
+      [3.4927, 65.4212, 0.5763, 1.6283, 0.76625, 1.2019],
+      1e-4),
      ( # gh-523
       [1.1 * 4 * np.pi**2], [1, 2 * 0.2 * 2 * np.pi,  4 * np.pi**2], .05,
-      [2.3842, 18.161, 0.26953, 11.712, 8.7478, 9.1504]),
+      [2.3842, 18.161, 0.26953, 11.712, 8.7478, 9.1504],
+      1e-4),
      ])
-def test_stability_margins_discrete(cnum, cden, dt, ref):
+def test_stability_margins_discrete(cnum, cden, dt, ref, rtol):
     """Test stability_margins with discrete TF input"""
     tf = TransferFunction(cnum, cden).sample(dt)
     out = stability_margins(tf)
-    assert_allclose(out, ref, rtol=1e-4)
+    assert_allclose(out, ref, rtol=rtol)
