Use np.ndarray in Variables

miplearn/solvers/__init__.py

@@ -4,7 +4,7 @@
 
 import logging
 import sys
-from typing import Any, List, TextIO, cast
+from typing import Any, List, TextIO, cast, TypeVar, Optional, Sized
 
 logger = logging.getLogger(__name__)
 
@@ -38,7 +38,10 @@ class _RedirectOutput:
         sys.stderr = self._original_stderr
 
 
-def _none_if_empty(obj: Any) -> Any:
+T = TypeVar("T", bound=Sized)
+
+
+def _none_if_empty(obj: T) -> Optional[T]:
     if len(obj) == 0:
         return None
     else:

miplearn/solvers/gurobi.py

@@ -6,8 +6,9 @@ import re
 import sys
 from io import StringIO
 from random import randint
-from typing import List, Any, Dict, Optional, Tuple, TYPE_CHECKING
+from typing import List, Any, Dict, Optional, TYPE_CHECKING
 
+import numpy as np
 from overrides import overrides
 
 from miplearn.instance.base import Instance
@@ -79,9 +80,9 @@ class GurobiSolver(InternalSolver):
         self._var_names: List[str] = []
         self._constr_names: List[str] = []
         self._var_types: List[str] = []
-        self._var_lbs: List[float] = []
-        self._var_ubs: List[float] = []
-        self._var_obj_coeffs: List[float] = []
+        self._var_lbs: np.ndarray = np.empty(0)
+        self._var_ubs: np.ndarray = np.empty(0)
+        self._var_obj_coeffs: np.ndarray = np.empty(0)
 
         if self.lazy_cb_frequency == 1:
             self.lazy_cb_where = [self.gp.GRB.Callback.MIPSOL]
@@ -338,15 +339,33 @@ class GurobiSolver(InternalSolver):
             )
 
             if with_sa:
-                sa_obj_up = model.getAttr("saobjUp", self._gp_vars)
-                sa_obj_down = model.getAttr("saobjLow", self._gp_vars)
-                sa_ub_up = model.getAttr("saubUp", self._gp_vars)
-                sa_ub_down = model.getAttr("saubLow", self._gp_vars)
-                sa_lb_up = model.getAttr("salbUp", self._gp_vars)
-                sa_lb_down = model.getAttr("salbLow", self._gp_vars)
+                sa_obj_up = np.array(
+                    model.getAttr("saobjUp", self._gp_vars),
+                    dtype=float,
+                )
+                sa_obj_down = np.array(
+                    model.getAttr("saobjLow", self._gp_vars),
+                    dtype=float,
+                )
+                sa_ub_up = np.array(
+                    model.getAttr("saubUp", self._gp_vars),
+                    dtype=float,
+                )
+                sa_ub_down = np.array(
+                    model.getAttr("saubLow", self._gp_vars),
+                    dtype=float,
+                )
+                sa_lb_up = np.array(
+                    model.getAttr("salbUp", self._gp_vars),
+                    dtype=float,
+                )
+                sa_lb_down = np.array(
+                    model.getAttr("salbLow", self._gp_vars),
+                    dtype=float,
+                )
 
         if model.solCount > 0:
-            values = model.getAttr("x", self._gp_vars)
+            values = np.array(model.getAttr("x", self._gp_vars), dtype=float)
 
         return Variables(
             names=self._var_names,
@@ -565,9 +584,18 @@ class GurobiSolver(InternalSolver):
         gp_constrs: List["gurobipy.Constr"] = self.model.getConstrs()
         var_names: List[str] = self.model.getAttr("varName", gp_vars)
         var_types: List[str] = self.model.getAttr("vtype", gp_vars)
-        var_ubs: List[float] = self.model.getAttr("ub", gp_vars)
-        var_lbs: List[float] = self.model.getAttr("lb", gp_vars)
-        var_obj_coeffs: List[float] = self.model.getAttr("obj", gp_vars)
+        var_ubs: np.ndarray = np.array(
+            self.model.getAttr("ub", gp_vars),
+            dtype=float,
+        )
+        var_lbs: np.ndarray = np.array(
+            self.model.getAttr("lb", gp_vars),
+            dtype=float,
+        )
+        var_obj_coeffs: np.ndarray = np.array(
+            self.model.getAttr("obj", gp_vars),
+            dtype=float,
+        )
         constr_names: List[str] = self.model.getAttr("constrName", gp_constrs)
         varname_to_var: Dict = {}
         cname_to_constr: Dict = {}

miplearn/solvers/internal.py

@@ -7,6 +7,8 @@ from abc import ABC, abstractmethod
 from dataclasses import dataclass
 from typing import Any, Optional, List, Tuple, TYPE_CHECKING
 
+import numpy as np
+
 from miplearn.instance.base import Instance
 from miplearn.types import (
     IterationCallback,
@@ -50,18 +52,18 @@ class MIPSolveStats:
 class Variables:
     names: Optional[List[str]] = None
     basis_status: Optional[List[str]] = None
-    lower_bounds: Optional[List[float]] = None
-    obj_coeffs: Optional[List[float]] = None
-    reduced_costs: Optional[List[float]] = None
-    sa_lb_down: Optional[List[float]] = None
-    sa_lb_up: Optional[List[float]] = None
-    sa_obj_down: Optional[List[float]] = None
-    sa_obj_up: Optional[List[float]] = None
-    sa_ub_down: Optional[List[float]] = None
-    sa_ub_up: Optional[List[float]] = None
+    lower_bounds: Optional[np.ndarray] = None
+    obj_coeffs: Optional[np.ndarray] = None
+    reduced_costs: Optional[np.ndarray] = None
+    sa_lb_down: Optional[np.ndarray] = None
+    sa_lb_up: Optional[np.ndarray] = None
+    sa_obj_down: Optional[np.ndarray] = None
+    sa_obj_up: Optional[np.ndarray] = None
+    sa_ub_down: Optional[np.ndarray] = None
+    sa_ub_up: Optional[np.ndarray] = None
     types: Optional[List[str]] = None
-    upper_bounds: Optional[List[float]] = None
-    values: Optional[List[float]] = None
+    upper_bounds: Optional[np.ndarray] = None
+    values: Optional[np.ndarray] = None
 
 
 @dataclass

miplearn/solvers/pyomo/base.py

@@ -330,11 +330,11 @@ class BasePyomoSolver(InternalSolver):
         return Variables(
             names=_none_if_empty(names),
             types=_none_if_empty(types),
-            upper_bounds=_none_if_empty(upper_bounds),
-            lower_bounds=_none_if_empty(lower_bounds),
-            obj_coeffs=_none_if_empty(obj_coeffs),
-            reduced_costs=_none_if_empty(reduced_costs),
-            values=_none_if_empty(values),
+            upper_bounds=_none_if_empty(np.array(upper_bounds, dtype=float)),
+            lower_bounds=_none_if_empty(np.array(lower_bounds, dtype=float)),
+            obj_coeffs=_none_if_empty(np.array(obj_coeffs, dtype=float)),
+            reduced_costs=_none_if_empty(np.array(reduced_costs, dtype=float)),
+            values=_none_if_empty(np.array(values, dtype=float)),
         )
 
     @overrides

miplearn/solvers/tests/__init__.py

@@ -41,10 +41,10 @@ def run_basic_usage_tests(solver: InternalSolver) -> None:
         solver.get_variables(),
         Variables(
             names=["x[0]", "x[1]", "x[2]", "x[3]", "z"],
-            lower_bounds=[0.0, 0.0, 0.0, 0.0, 0.0],
-            upper_bounds=[1.0, 1.0, 1.0, 1.0, 67.0],
+            lower_bounds=np.array([0.0, 0.0, 0.0, 0.0, 0.0]),
+            upper_bounds=np.array([1.0, 1.0, 1.0, 1.0, 67.0]),
             types=["B", "B", "B", "B", "C"],
-            obj_coeffs=[505.0, 352.0, 458.0, 220.0, 0.0],
+            obj_coeffs=np.array([505.0, 352.0, 458.0, 220.0, 0.0]),
         ),
     )
 
@@ -85,14 +85,18 @@ def run_basic_usage_tests(solver: InternalSolver) -> None:
             Variables(
                 names=["x[0]", "x[1]", "x[2]", "x[3]", "z"],
                 basis_status=["U", "B", "U", "L", "U"],
-                reduced_costs=[193.615385, 0.0, 187.230769, -23.692308, 13.538462],
-                sa_lb_down=[-inf, -inf, -inf, -0.111111, -inf],
-                sa_lb_up=[1.0, 0.923077, 1.0, 1.0, 67.0],
-                sa_obj_down=[311.384615, 317.777778, 270.769231, -inf, -13.538462],
-                sa_obj_up=[inf, 570.869565, inf, 243.692308, inf],
-                sa_ub_down=[0.913043, 0.923077, 0.9, 0.0, 43.0],
-                sa_ub_up=[2.043478, inf, 2.2, inf, 69.0],
-                values=[1.0, 0.923077, 1.0, 0.0, 67.0],
+                reduced_costs=np.array(
+                    [193.615385, 0.0, 187.230769, -23.692308, 13.538462]
+                ),
+                sa_lb_down=np.array([-inf, -inf, -inf, -0.111111, -inf]),
+                sa_lb_up=np.array([1.0, 0.923077, 1.0, 1.0, 67.0]),
+                sa_obj_down=np.array(
+                    [311.384615, 317.777778, 270.769231, -inf, -13.538462]
+                ),
+                sa_obj_up=np.array([inf, 570.869565, inf, 243.692308, inf]),
+                sa_ub_down=np.array([0.913043, 0.923077, 0.9, 0.0, 43.0]),
+                sa_ub_up=np.array([2.043478, inf, 2.2, inf, 69.0]),
+                values=np.array([1.0, 0.923077, 1.0, 0.0, 67.0]),
             ),
         ),
     )
@@ -137,7 +141,7 @@ def run_basic_usage_tests(solver: InternalSolver) -> None:
             solver.get_variable_attrs(),
             Variables(
                 names=["x[0]", "x[1]", "x[2]", "x[3]", "z"],
-                values=[1.0, 0.0, 1.0, 1.0, 61.0],
+                values=np.array([1.0, 0.0, 1.0, 1.0, 61.0]),
             ),
         ),
     )

tests/components/test_primal.py

@@ -24,7 +24,7 @@ def sample() -> Sample:
         {
             "static_var_names": ["x[0]", "x[1]", "x[2]", "x[3]"],
             "static_var_categories": ["default", None, "default", "default"],
-            "mip_var_values": [0.0, 1.0, 1.0, 0.0],
+            "mip_var_values": np.array([0.0, 1.0, 1.0, 0.0]),
             "static_instance_features": [5.0],
             "static_var_features": [
                 [0.0, 0.0],

tests/features/test_extractor.py

@@ -32,7 +32,8 @@ def test_knapsack() -> None:
     # -------------------------------------------------------
     extractor.extract_after_load_features(instance, solver, sample)
     assert_equals(
-        sample.get_vector("static_var_names"), ["x[0]", "x[1]", "x[2]", "x[3]", "z"]
+        sample.get_vector("static_var_names"),
+        ["x[0]", "x[1]", "x[2]", "x[3]", "z"],
     )
     assert_equals(
         sample.get_vector("static_var_lower_bounds"), [0.0, 0.0, 0.0, 0.0, 0.0]

tests/instance/test_file.py

@@ -17,7 +17,7 @@ def test_usage() -> None:
     # Save instance to disk
     filename = tempfile.mktemp()
     FileInstance.save(original, filename)
-    sample = Hdf5Sample(filename)
+    sample = Hdf5Sample(filename, check_data=True)
     assert len(sample.get_bytes("pickled")) > 0
 
     # Solve instance from disk

tests/problems/test_tsp.py

@@ -9,6 +9,7 @@ from scipy.stats import uniform, randint
 
 from miplearn.problems.tsp import TravelingSalesmanGenerator, TravelingSalesmanInstance
 from miplearn.solvers.learning import LearningSolver
+from miplearn.solvers.tests import assert_equals
 
 
 def test_generator() -> None:
@@ -41,7 +42,7 @@ def test_instance() -> None:
     solver.solve(instance)
     assert len(instance.get_samples()) == 1
     sample = instance.get_samples()[0]
-    assert sample.get_vector("mip_var_values") == [1.0, 0.0, 1.0, 1.0, 0.0, 1.0]
+    assert_equals(sample.get_vector("mip_var_values"), [1.0, 0.0, 1.0, 1.0, 0.0, 1.0])
     assert sample.get_scalar("mip_lower_bound") == 4.0
     assert sample.get_scalar("mip_upper_bound") == 4.0
 
@@ -68,7 +69,9 @@ def test_subtour() -> None:
     lazy_enforced = sample.get_set("mip_constr_lazy_enforced")
     assert lazy_enforced is not None
     assert len(lazy_enforced) > 0
-    assert sample.get_vector("mip_var_values") == [
+    assert_equals(
+        sample.get_vector("mip_var_values"),
+        [
             1.0,
             0.0,
             0.0,
@@ -84,6 +87,7 @@ def test_subtour() -> None:
             0.0,
             1.0,
             1.0,
-    ]
+        ],
+    )
     solver.fit([instance])
     solver.solve(instance)

tests/solvers/test_learning_solver.py

@@ -38,7 +38,9 @@ def test_learning_solver(
             assert len(instance.get_samples()) > 0
             sample = instance.get_samples()[0]
 
-            assert sample.get_vector("mip_var_values") == [1.0, 0.0, 1.0, 1.0, 61.0]
+            assert_equals(
+                sample.get_vector("mip_var_values"), [1.0, 0.0, 1.0, 1.0, 61.0]
+            )
             assert sample.get_scalar("mip_lower_bound") == 1183.0
             assert sample.get_scalar("mip_upper_bound") == 1183.0
             mip_log = sample.get_scalar("mip_log")