Add first model feature (constraint RHS)

miplearn/solvers/gurobi.py

@@ -335,6 +335,10 @@ class GurobiSolver(InternalSolver):
         self.model.update()
         return [c.ConstrName for c in self.model.getConstrs()]
 
+    def get_constraint_rhs(self, cid: str) -> float:
+        assert self.model is not None
+        return self.model.getConstrByName(cid).rhs
+
     def extract_constraint(self, cid):
         self._raise_if_callback()
         constr = self.model.getConstrByName(cid)

miplearn/solvers/internal.py

@@ -155,6 +155,13 @@ class InternalSolver(ABC):
         """
         pass
 
+    @abstractmethod
+    def get_constraint_rhs(self, cid: str) -> float:
+        """
+        Returns the right-hand side of a given constraint.
+        """
+        pass
+
     @abstractmethod
     def add_constraint(self, cobj: Constraint) -> None:
         """

miplearn/solvers/learning.py

@@ -16,11 +16,12 @@ from miplearn.components.cuts import UserCutsComponent
 from miplearn.components.lazy_dynamic import DynamicLazyConstraintsComponent
 from miplearn.components.objective import ObjectiveValueComponent
 from miplearn.components.primal import PrimalSolutionComponent
+from miplearn.features import ModelFeaturesExtractor
 from miplearn.instance import Instance
 from miplearn.solvers import _RedirectOutput
 from miplearn.solvers.internal import InternalSolver
 from miplearn.solvers.pyomo.gurobi import GurobiPyomoSolver
-from miplearn.types import MIPSolveStats, TrainingSample, LearningSolveStats
+from miplearn.types import TrainingSample, LearningSolveStats
 
 logger = logging.getLogger(__name__)
 
@@ -164,6 +165,10 @@ class LearningSolver:
         assert isinstance(self.internal_solver, InternalSolver)
         self.internal_solver.set_instance(instance, model)
 
+        # Extract model features
+        extractor = ModelFeaturesExtractor(self.internal_solver)
+        instance.model_features = extractor.extract()
+
         # Solve linear relaxation
         if self.solve_lp_first:
             logger.info("Solving LP relaxation...")

miplearn/solvers/pyomo/base.py

@@ -212,7 +212,11 @@ class BasePyomoSolver(InternalSolver):
         assert self.model is not None
         self._cname_to_constr = {}
         for constr in self.model.component_objects(Constraint):
-            self._cname_to_constr[constr.name] = constr
+            if isinstance(constr, pe.ConstraintList):
+                for idx in constr:
+                    self._cname_to_constr[f"{constr.name}[{idx}]"] = constr[idx]
+            else:
+                self._cname_to_constr[constr.name] = constr
 
     def fix(self, solution):
         count_total, count_fixed = 0, 0
@@ -302,6 +306,13 @@ class BasePyomoSolver(InternalSolver):
         else:
             return "="
 
+    def get_constraint_rhs(self, cid: str) -> float:
+        cobj = self._cname_to_constr[cid]
+        if cobj.has_ub:
+            return cobj.upper()
+        else:
+            return cobj.lower()
+
     def set_constraint_sense(self, cid: str, sense: str) -> None:
         raise Exception("Not implemented")