Organize test fixtures; handle infeasibility in DropRedundant

miplearn/components/steps/drop_redundant.py

@@ -32,7 +32,7 @@ class DropRedundantInequalitiesStep(Component):
         classifier=CountingClassifier(),
         threshold=0.95,
         slack_tolerance=1e-5,
-        check_feasibility=False,
+        check_feasibility=True,
         violation_tolerance=1e-5,
         max_iterations=3,
     ):
@@ -208,6 +208,8 @@ class DropRedundantInequalitiesStep(Component):
             return False
         if self.current_iteration >= self.max_iterations:
             return False
+        if solver.internal_solver.is_infeasible():
+            return False
         self.current_iteration += 1
         logger.debug("Checking that dropped constraints are satisfied...")
         constraints_to_add = []

miplearn/solvers/gurobi.py

@@ -342,7 +342,7 @@ class GurobiSolver(InternalSolver):
         self.model.remove(constr)
         return cobj
 
-    def is_constraint_satisfied(self, cobj, tol=1e-5):
+    def is_constraint_satisfied(self, cobj, tol=1e-6):
         lhs, sense, rhs, name = cobj
         if self.cb_where is not None:
             lhs_value = lhs.getConstant()
@@ -378,6 +378,7 @@ class GurobiSolver(InternalSolver):
 
     def relax(self) -> None:
         assert self.model is not None
+        self.model.update()
         self.model = self.model.relax()
         self._update_vars()
 

miplearn/solvers/internal.py

@@ -173,7 +173,7 @@ class InternalSolver(ABC):
         pass
 
     @abstractmethod
-    def is_constraint_satisfied(self, cobj: Constraint) -> bool:
+    def is_constraint_satisfied(self, cobj: Constraint, tol: float = 1e-6) -> bool:
         """
         Returns True if the current solution satisfies the given constraint.
         """

miplearn/solvers/pyomo/base.py

@@ -308,7 +308,7 @@ class BasePyomoSolver(InternalSolver):
     def extract_constraint(self, cid: str) -> Constraint:
         raise Exception("Not implemented")
 
-    def is_constraint_satisfied(self, cobj: Constraint) -> bool:
+    def is_constraint_satisfied(self, cobj: Constraint, tol: float = 1e-6) -> bool:
         raise Exception("Not implemented")
 
     def is_infeasible(self) -> bool: