# MIPLearn: Extensible Framework for Learning-Enhanced Mixed-Integer Optimization # Copyright (C) 2020-2021, UChicago Argonne, LLC. All rights reserved. # Released under the modified BSD license. See COPYING.md for more details. from miplearn.features import ( FeaturesExtractor, InstanceFeatures, Constraint, VariableFeatures, ) from miplearn.solvers.gurobi import GurobiSolver from miplearn.solvers.tests import ( assert_equals, _round_constraints, _round, ) inf = float("inf") def test_knapsack() -> None: solver = GurobiSolver() instance = solver.build_test_instance_knapsack() model = instance.to_model() solver.set_instance(instance, model) solver.solve_lp() features = FeaturesExtractor().extract(instance, solver) assert features.variables is not None assert features.constraints is not None assert features.instance is not None assert_equals( _round(features.variables), VariableFeatures( names=("x[0]", "x[1]", "x[2]", "x[3]", "z"), basis_status=("U", "B", "U", "L", "U"), categories=("default", "default", "default", "default", None), lower_bounds=(0.0, 0.0, 0.0, 0.0, 0.0), obj_coeffs=(505.0, 352.0, 458.0, 220.0, 0.0), 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), types=("B", "B", "B", "B", "C"), upper_bounds=(1.0, 1.0, 1.0, 1.0, 67.0), user_features=( (23.0, 505.0), (26.0, 352.0), (20.0, 458.0), (18.0, 220.0), None, ), values=(1.0, 0.923077, 1.0, 0.0, 67.0), alvarez_2017=[ [1.0, 0.32899, 0.0, 0.0, 1.0, 1.0, 5.265874, 46.051702], [1.0, 0.229316, 0.0, 0.076923, 1.0, 1.0, 3.532875, 5.388476], [1.0, 0.298371, 0.0, 0.0, 1.0, 1.0, 5.232342, 46.051702], [1.0, 0.143322, 0.0, 0.0, 1.0, -1.0, 46.051702, 3.16515], [0.0, 0.0, 0.0, 0.0, 1.0, -1.0, 0.0, 0.0], ], ), ) assert_equals( _round_constraints(features.constraints), { "eq_capacity": Constraint( basis_status="N", category="eq_capacity", dual_value=13.538462, lazy=False, lhs={"x[0]": 23.0, "x[1]": 26.0, "x[2]": 20.0, "x[3]": 18.0, "z": -1.0}, rhs=0.0, sa_rhs_down=-24.0, sa_rhs_up=1.9999999999999987, sense="=", slack=0.0, user_features=[0.0], ) }, ) assert_equals( features.instance, InstanceFeatures( user_features=[67.0, 21.75], lazy_constraint_count=0, ), )