98 lines
3.2 KiB
Python
98 lines
3.2 KiB
Python
from __future__ import annotations
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from typing import TYPE_CHECKING
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from pydantic import BaseModel
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from typing import Any, List
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from pulp import LpProblem, LpVariable, lpSum
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import logging
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from models.solution import Solution
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from models.item import Item
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from models.bundle import Bundle
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from lib.errors.item_generation_error import ItemGenerationError
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if TYPE_CHECKING:
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from models.solver_run import SolverRun
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class Problem(BaseModel):
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items: List[Item]
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bundles: List[Bundle]
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problem: Any
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solver_items_var: Any = None
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solver_bundles_var: Any = None
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def __init__(self, **data) -> None:
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super().__init__(**data)
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# setup common Solver variables
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self.solver_items_var = LpVariable.dicts("Item",
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[item.id for item in self.items],
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lowBound=0,
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upBound=1,
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cat='Binary')
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self.solver_bundles_var = LpVariable.dicts("Bundle",
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[bundle.id for bundle in self.bundles],
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lowBound=0,
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upBound=1,
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cat='Binary')
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# objective function
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self.problem += lpSum([
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bundle.count * self.solver_bundles_var[bundle.id]
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for bundle in self.bundles
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] + [
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self.solver_items_var[item.id]
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for item in self.items
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])
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def solve(self) -> LpProblem:
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self.problem.solve()
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return self.problem
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def generate(self, solution: Solution, solver_run: SolverRun) -> None:
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# Objective Function
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self.problem += lpSum(
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[
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bundle.count * self.solver_bundles_var[bundle.id]
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for bundle in self.bundles
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] + [
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1 * self.solver_items_var[item.id]
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for item in self.items
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]
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) == solver_run.total_form_items, f'Total bundle form items for form'
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# each time a form is generated, we want to ensure
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# that it is unique to all other forms generated before it
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self.problem += lpSum(
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[
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solution.items_exist_in_forms(bundle.items) * self.solver_bundles_var[bundle.id]
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for bundle in self.bundles
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] + [
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solution.items_exist_in_forms([item]) * self.solver_items_var[item.id]
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for item in self.items
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]
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) <= solver_run.total_form_items - 1, f'Ensuring uniqueness for form'
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def generate_constraints(self, solver_run: SolverRun, current_drift: int) -> None:
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logging.info('Creating Constraints...')
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try:
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for constraint in solver_run.constraints:
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constraint.build(self, solver_run)
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for target in solver_run.objective_function.all_targets():
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target.build_constraint(self, solver_run)
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logging.info('Constraints Created...')
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except ValueError as error:
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logging.error(error)
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raise ItemGenerationError(
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error.msg,
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error.args[0])
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