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65 lines
1.9 KiB
65 lines
1.9 KiB
# MIPLearn: Extensible Framework for Learning-Enhanced Mixed-Integer Optimization
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# Copyright (C) 2020, UChicago Argonne, LLC. All rights reserved.
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# Released under the modified BSD license. See COPYING.md for more details.
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from typing import Any, TYPE_CHECKING, Hashable, Set
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from miplearn import Component, Instance
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import logging
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from miplearn.features import Features, TrainingSample
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from miplearn.types import LearningSolveStats
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logger = logging.getLogger(__name__)
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if TYPE_CHECKING:
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from miplearn.solvers.learning import LearningSolver
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class UserCutsComponentNG(Component):
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def __init__(self) -> None:
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self.enforced: Set[Hashable] = set()
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def before_solve_mip(
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self,
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solver: "LearningSolver",
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instance: Instance,
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model: Any,
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stats: LearningSolveStats,
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features: Features,
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training_data: TrainingSample,
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) -> None:
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self.enforced.clear()
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def after_solve_mip(
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self,
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solver: "LearningSolver",
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instance: Instance,
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model: Any,
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stats: LearningSolveStats,
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features: Features,
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training_data: TrainingSample,
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) -> None:
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training_data.user_cuts_enforced = set(self.enforced)
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def user_cut_cb(
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self,
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solver: "LearningSolver",
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instance: Instance,
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model: Any,
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) -> None:
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assert solver.internal_solver is not None
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logger.debug("Finding violated user cuts...")
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cids = instance.find_violated_user_cuts(model)
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logger.debug(f"Found {len(cids)} violated user cuts")
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logger.debug("Building violated user cuts...")
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for cid in cids:
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assert isinstance(cid, Hashable)
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cobj = instance.build_user_cut(model, cid)
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assert cobj is not None
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solver.internal_solver.add_cut(cobj)
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self.enforced.add(cid)
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if len(cids) > 0:
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logger.info(f"Added {len(cids)} violated user cuts")
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