优化仿真求解性能并修复流量闭合问题（初版）

tests/test_amesim_pnvo001_fixed_component.py

@@ -64,6 +64,23 @@ class AmesimPnvo001FixedOpeningComponentTests(unittest.TestCase):
         self.assertLess(reverse, 0.0)
         self.assertAlmostEqual(forward, -reverse)
 
+    def test_mass_flow_is_continuous_across_former_relative_deadband(self) -> None:
+        valve = AmesimPnvo001FixedOpening("valve_1", self.medium, opening=0.5)
+        base_pressure = 8.0e6
+        former_threshold = base_pressure * 1.0e-7
+
+        below = valve.mass_flow(base_pressure + 0.99 * former_threshold, base_pressure)
+        above = valve.mass_flow(base_pressure + 1.01 * former_threshold, base_pressure)
+        reverse = valve.mass_flow(base_pressure, base_pressure + 0.99 * former_threshold)
+
+        self.assertGreater(below, 0.0)
+        self.assertGreater(above, below)
+        self.assertLess(reverse, 0.0)
+        self.assertAlmostEqual(below, -reverse, delta=abs(below) * 1.0e-9)
+        self.assertLess(abs(above - below), abs(above) * 0.05)
+        self.assertEqual(valve.mass_flow(base_pressure, base_pressure), 0.0)
+        self.assertGreater(valve.mass_flow(15.3e6 + 0.1, 15.3e6), 0.0)
+
     def test_mass_flow_uses_connected_enthalpy_from_the_upstream_side(self) -> None:
         valve = AmesimPnvo001FixedOpening("valve_1", self.medium, opening=0.5)
         hot_h = self.medium.specific_enthalpy(600.0)