94 lines
3.4 KiB
Python
94 lines
3.4 KiB
Python
#!/usr/bin/env python3
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# Copyright 2010-2022 Google LLC
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Unit tests for solve.py that require using Gurobi as the underlying solver.
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These tests are in a separate file because Gurobi can only run on a licensed
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machine.
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"""
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import unittest
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from ortools.math_opt.python import callback
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from ortools.math_opt.python import compute_infeasible_subsystem_result
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from ortools.math_opt.python import model
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from ortools.math_opt.python import parameters
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from ortools.math_opt.python import result
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from ortools.math_opt.python import solve
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_Bounds = compute_infeasible_subsystem_result.ModelSubsetBounds
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class SolveTest(unittest.TestCase):
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def test_callback(self) -> None:
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mod = model.Model(name="test_model")
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# Solve the problem:
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# max x + 2 * y
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# s.t. x + y <= 1 (added in callback)
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# x, y in {0, 1}
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# Primal optimal: [x, y] = [0.0, 1.0]
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x = mod.add_binary_variable(name="x")
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y = mod.add_binary_variable(name="y")
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mod.objective.is_maximize = True
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mod.objective.set_linear_coefficient(x, 1.0)
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mod.objective.set_linear_coefficient(y, 2.0)
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def cb(cb_data: callback.CallbackData) -> callback.CallbackResult:
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cb_res = callback.CallbackResult()
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if cb_data.solution[x] + cb_data.solution[y] >= 1 + 1e-4:
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cb_res.add_lazy_constraint(x + y <= 1.0)
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return cb_res
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cb_reg = callback.CallbackRegistration()
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cb_reg.events.add(callback.Event.MIP_SOLUTION)
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cb_reg.add_lazy_constraints = True
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params = parameters.SolveParameters(enable_output=True)
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res = solve.solve(
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mod,
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parameters.SolverType.GUROBI,
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params=params,
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callback_reg=cb_reg,
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cb=cb,
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)
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self.assertEqual(
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res.termination.reason,
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result.TerminationReason.OPTIMAL,
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msg=res.termination,
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)
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self.assertAlmostEqual(2.0, res.termination.objective_bounds.primal_bound)
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def test_compute_infeasible_subsystem_infeasible(self):
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mod = model.Model()
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x = mod.add_variable(lb=0.0, ub=1.0)
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y = mod.add_variable(lb=0.0, ub=1.0)
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z = mod.add_variable(lb=0.0, ub=1.0)
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mod.add_linear_constraint(x + y <= 4.0)
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d = mod.add_linear_constraint(x + z >= 3.0)
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iis = solve.compute_infeasible_subsystem(mod, parameters.SolverType.GUROBI)
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self.assertTrue(iis.is_minimal)
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self.assertEqual(iis.feasibility, result.FeasibilityStatus.INFEASIBLE)
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self.assertDictEqual(
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iis.infeasible_subsystem.variable_bounds,
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{x: _Bounds(upper=True), z: _Bounds(upper=True)},
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)
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self.assertDictEqual(
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iis.infeasible_subsystem.linear_constraints, {d: _Bounds(lower=True)}
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)
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self.assertEmpty(iis.infeasible_subsystem.variable_integrality)
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if __name__ == "__main__":
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unittest.main()
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