Flow Shop¶
Flow Shop¶
所有工件按相同的工序顺序经过多个阶段。除阶段内容量外，还要把同一个工件
在前后阶段的完成/开始关系串起来。flow_shop.py 使用 sequence、interval
和 precedence 描述该结构，并通过统一的 solve(...) 入口求解。
完整代码¶
examples/scheduling/flow_shop.py
from __future__ import annotations
from pathlib import Path
import sys
from optagent import ModelBuilder, solve
sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
from _common import print_solution
def build_model() -> tuple[object, int]:
builder = ModelBuilder(metadata={"case": "flow_shop"})
seq = builder.sequence_var(size=3, default=[2, 1, 0], name="machine_order")
cut = builder.interval_var(start=0, length=2, lb_start=0, ub_start=5, lb_length=2, ub_length=2, name="cut")
drill = builder.interval_var(start=0, length=3, lb_start=0, ub_start=6, lb_length=3, ub_length=3, name="drill")
pack = builder.interval_var(start=0, length=1, lb_start=0, ub_start=8, lb_length=1, ub_length=1, name="pack")
builder.constraint(builder.no_overlap(seq, cut, drill, pack), name="machine_capacity")
builder.constraint(builder.precedence(cut, drill, lag=0), name="cut_before_drill")
builder.constraint(builder.precedence(drill, pack, lag=0), name="drill_before_pack")
builder.minimize(builder.interval_end(pack), name="makespan")
return builder.freeze(), seq.node_id
def main() -> None:
program, sequence_id = build_model()
solution = solve(program, time_limit_s=10.0, seed=7, threads=1, log_level="on")
print_solution("flow shop solved by unified solve", solution, extra={"sequence_variable": sequence_id})
if __name__ == "__main__":
main()