验收四路模型并优化拓扑求解性能

app/simulation/solvers/mechanical.py

@@ -391,6 +391,27 @@ class MechanicalStateReducer:
     def has_state_events(self) -> bool:
         return any(group.discrete_endstop_components for group in self.groups)
 
+    def absolute_tolerances(
+        self,
+        default: float,
+        *,
+        mechanical: float = 1.0e-12,
+    ) -> list[float]:
+        """Return state-aligned tolerances with machine-scale mechanics.
+
+        A scalar ``1e-8`` absolute tolerance makes SciPy perturb a zero-valued
+        endstop position across the much smaller unilateral boundary band while
+        constructing finite-difference Jacobians. Mechanical coordinates need
+        a tighter floor; thermodynamic states retain the caller's tolerance.
+        """
+        values: list[float] = []
+        for entry in self.state_entries:
+            if isinstance(entry, MechanicalConstraintGroup):
+                values.extend([min(default, mechanical)] * 2)
+            else:
+                values.extend([default] * entry.state_size)
+        return values
+
     def reset_constraint_modes(self) -> None:
         for group in self.groups:
             group.reset_mode()
@@ -518,7 +539,7 @@ class MechanicalStateReducer:
                 candidates.append((previous_time, group, "lower", lower))
             elif (
                 lower is not None
-                and previous_position > lower
+                and previous_position > lower + group._boundary_tolerance(lower)
                 and current_position <= lower
             ):
                 candidates.append(
@@ -573,7 +594,7 @@ class MechanicalStateReducer:
                 candidates.append((previous_time, group, "upper", upper))
             elif (
                 upper is not None
-                and previous_position < upper
+                and previous_position < upper - group._boundary_tolerance(upper)
                 and current_position >= upper
             ):
                 candidates.append(