Gurobi Python 错误：列表索引超出范围

如何解决Gurobi Python 错误：列表索引超出范围

在 Zeppelin（oracle 数据工作室）中与 Gurobi 合作，我不断收到列表索引错误。这是代码和错误消息。 Gurobi 的新手，非常感谢任何有关如何解决此问题的有用意见。

将变量（数量）添加到模型（交易）时似乎出现错误

%python
import numpy as np
import pandas as pd
import gurobipy as gp
from gurobipy import *
from rsecommon.analytics.gurobi import *
try:

    instance = rseenv.RseGurobiEnv.getInstance()
    env = instance.getGurobiEnv()
    # Model
    deal = Model("Deal Optimization",env)
    
    # Parameters
    items = ['item1','item2','item3','item4','item5','item6','item7','item8','item9','item10']
    volumes = {'item1':1,'item2':1,'item3':2,'item4':2,'item5':3,'item6':3,'item7':4,'item8':4,'item9':5,'item10':5}
    discounts = {'item1':0.05,'item2':0.04,'item3':0.01,'item4':0.08,'item5':0.06,'item6':0.02,'item7':0.01,'item8':0.09,'item9':0.06,'item10':0.09}
    min_qty = {'item1':540,'item2':70,'item3':220,'item4':170,'item5':60,'item6':850,'item7':910,'item8':310,'item9':480,'item10':60}

    capacity_cap = 5000

    # Variables
    quantity = deal.addVars(items,ub = (5000/volumes[item] for item in volumes),name='quantity')
    
    # Constraints
    deal.addConstr(((gp.quicksum(volumes[item]*quantity[item] for item in volumes) <= capacity_cap )),"Capacity")

    # Set objective
    deal.setobjective(quantity.prod(discounts),GRB.MAXIMIZE) 

    # Optimize
    deal.optimize()

    for v in deal.getvars():
        print('%s %g' % (v.varName,v.x))

    print('Obj: %g' % deal.objVal)

except GurobiError as e:
    print('Error code ' + str(e.errno) + ": " + str(e.message))

except AttributeError:
    print('Enco111untered an attribute error')

错误信息：

Traceback (most recent call last):
  File "/tmp/zeppelin_python-2988405025033753797.py",line 312,in <module>
    exec(code,_zcUserQueryNameSpace)
  File "<stdin>",line 15,in <module>
  File "model.pxi",line 2496,in gurobipy.Model.addVars
IndexError: list index out of range

During handling of the above exception,another exception occurred:

Traceback (most recent call last):
  File "/tmp/zeppelin_python-2988405025033753797.py",line 319,in <module>
    raise Exception(traceback.format_exc())
Exception: Traceback (most recent call last):
  File "/tmp/zeppelin_python-2988405025033753797.py",in gurobipy.Model.addVars
IndexError: list index out of range

解决方法

尝试在对 Model.addVars 的调用中对 UB 值使用字典：

quantity = deal.addVars(items,ub = {item:5000/volumes[item] for item in items},name='quantity')