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MIPLearn/miplearn/tests/test_solver.py

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# MIPLearn, an extensible framework for Learning-Enhanced Mixed-Integer Optimization
# Copyright (C) 2019-2020 Argonne National Laboratory. All rights reserved.
# Written by Alinson S. Xavier <axavier@anl.gov>
from miplearn import LearningSolver
from miplearn.problems.knapsack import KnapsackInstance2
from miplearn.branching import BranchPriorityComponent
from miplearn.warmstart import WarmStartComponent
import numpy as np
def test_solver():
instance = KnapsackInstance2(weights=[23., 26., 20., 18.],
prices=[505., 352., 458., 220.],
capacity=67.)
solver = LearningSolver()
solver.solve(instance)
solver.fit()
solver.solve(instance)
def test_solve_save_load_state():
instance = KnapsackInstance2(weights=[23., 26., 20., 18.],
prices=[505., 352., 458., 220.],
capacity=67.)
components_before = {
"warm-start": WarmStartComponent(),
"branch-priority": BranchPriorityComponent(),
}
solver = LearningSolver(components=components_before)
solver.solve(instance)
solver.fit()
solver.save_state("/tmp/knapsack_train.bin")
prev_x_train_len = len(solver.components["warm-start"].x_train)
prev_y_train_len = len(solver.components["warm-start"].y_train)
components_after = {
"warm-start": WarmStartComponent(),
}
solver = LearningSolver(components=components_after)
solver.load_state("/tmp/knapsack_train.bin")
assert len(solver.components.keys()) == 1
assert len(solver.components["warm-start"].x_train) == prev_x_train_len
assert len(solver.components["warm-start"].y_train) == prev_y_train_len
def test_parallel_solve():
instances = [KnapsackInstance2(weights=np.random.rand(5),
prices=np.random.rand(5),
capacity=3.0)
for _ in range(10)]
solver = LearningSolver()
results = solver.parallel_solve(instances, n_jobs=3)
assert len(results) == 10
assert len(solver.components["warm-start"].x_train[0]) == 10
assert len(solver.components["warm-start"].y_train[0]) == 10
def test_solver_random_branch_priority():
instance = KnapsackInstance2(weights=[23., 26., 20., 18.],
prices=[505., 352., 458., 220.],
capacity=67.)
components = {
"warm-start": BranchPriorityComponent(initial_priority=np.array([1, 2, 3, 4])),
}
solver = LearningSolver(components=components)
solver.solve(instance)
solver.fit()