irt-service/app/helpers/solver_helper.py
2022-03-23 13:12:16 +00:00

92 lines
3.6 KiB
Python

from pulp import lpSum, LpProblem
from random import randint, sample
import logging
from helpers.common_helper import *
from models.bundle import Bundle
from models.solver_run import SolverRun
from models.item import Item
from lib.errors.item_generation_error import ItemGenerationError
def build_constraints(solver_run: SolverRun, problem: LpProblem,
items: list[Item], bundles: list[Bundle]) -> LpProblem:
logging.info('Creating Constraints...')
try:
total_form_items = solver_run.total_form_items
constraints = solver_run.constraints
for constraint in constraints:
attribute = constraint.reference_attribute
min = constraint.minimum
max = constraint.maximum
if attribute.type == 'metadata':
logging.info('Metadata Constraint Generating...')
con = dict(
zip([item.id for item in solver_run.items], [
boolean_to_int(item.attribute_exists(attribute))
for item in solver_run.items
]))
problem += lpSum(
[
len(bundle.items_with_attribute(attribute)) * bundles[bundle.id] for bundle in solver_run.bundles
] +
[
con[item.id] * items[item.id] for item in solver_run.unbundled_items()
]
) >= round(total_form_items * (min / 100)), f'{attribute.id} - {attribute.value} - min'
problem += lpSum(
[
len(bundle.items_with_attribute(attribute)) * bundles[bundle.id] for bundle in solver_run.bundles
] +
[
con[item.id] * items[item.id] for item in solver_run.unbundled_items()
]
) <= round(total_form_items * (max / 100)), f'{attribute.id} - {attribute.value} - max'
elif attribute.type == 'bundle':
logging.info('Bundles Constraint Generating...')
# TODO: account for many different bundle types, since the id condition in L33 could yield duplicates
if solver_run.bundles != None:
# make sure the total bundles used in generated form is limited between min-max set
problem += lpSum([
bundles[bundle.id] for bundle in solver_run.bundles
]) == randint(int(constraint.minimum),
int(constraint.maximum))
logging.info('Constraints Created...')
return problem
except ValueError as error:
logging.error(error)
raise ItemGenerationError(
"Bundle min and/or max larger than bundle amount provided",
error.args[0])
def get_random_bundles(total_form_items: int,
bundles: list[Bundle],
min: int,
max: int,
found_bundles=False) -> list[Bundle]:
selected_bundles = None
total_bundle_items = 0
total_bundles = randint(min, max)
logging.info(f'Selecting Bundles (total of {total_bundles})...')
while found_bundles == False:
selected_bundles = sample(bundles, total_bundles)
total_bundle_items = sum(bundle.count for bundle in selected_bundles)
if total_bundle_items <= total_form_items:
found_bundles = True
if found_bundles == True:
return selected_bundles
else:
return get_random_bundles(total_form_items, total_bundles - 1, bundles)