Pyomo说我的模型没有定义

嗨，我正在测试我的Pyomo安装，当我尝试解决任何优化问题时，它会返回一个错误，内容如下：

“退出pyomo求解：未定义模型，模块test.py中未提供'pyomo_create_model'”

我正在执行

pyomo解决test.py diet.dat --solver = glpk

from pyomo.environ import *
infinity = float('inf')

model = AbstractModel()

# Foods
model.F = Set()
# Nutrients
model.N = Set()

# Cost of each food
model.c    = Param(model.F, within=PositiveReals)
# Amount of nutrient in each food
model.a    = Param(model.F, model.N, within=NonNegativeReals)
# Lower and upper bound on each nutrient
model.Nmin = Param(model.N, within=NonNegativeReals, default=0.0)
model.Nmax = Param(model.N, within=NonNegativeReals, default=infinity)
# Volume per serving of food
model.V    = Param(model.F, within=PositiveReals)
# Maximum volume of food consumed
model.Vmax = Param(within=PositiveReals)

# Number of servings consumed of each food
model.x = Var(model.F, within=NonNegativeIntegers)

# Minimize the cost of food that is consumed
def cost_rule(model):
    return sum(model.c[i]*model.x[i] for i in model.F)
model.cost = Objective(rule=cost_rule)

# Limit nutrient consumption for each nutrient
def nutrient_rule(model, j):
    value = sum(model.a[i,j]*model.x[i] for i in model.F)
    return model.Nmin[j] <= value <= model.Nmax[j]
model.nutrient_limit = Constraint(model.N, rule=nutrient_rule)

# Limit the volume of food consumed
def volume_rule(model):
    return sum(model.V[i]*model.x[i] for i in model.F) <= model.Vmax
model.volume = Constraint(rule=volume_rule)

和我的diet.dat文件是

param:  F:                          c     V  :=
  "Cheeseburger"                 1.84   4.0  
  "Ham Sandwich"                 2.19   7.5  
  "Hamburger"                    1.84   3.5  
  "Fish Sandwich"                1.44   5.0  
  "Chicken Sandwich"             2.29   7.3  
  "Fries"                         .77   2.6  
  "Sausage Biscuit"              1.29   4.1  
  "Lowfat Milk"                   .60   8.0 
  "Orange Juice"                  .72  12.0 ;

param Vmax := 75.0;

param:  N:       Nmin   Nmax :=
        Cal      2000      .
        Carbo     350    375
        Protein    55      .
        VitA      100      .
        VitC      100      .
        Calc      100      .
        Iron      100      . ;

param a:
                               Cal  Carbo Protein   VitA   VitC  Calc  Iron :=
  "Cheeseburger"               510     34     28     15      6    30    20
  "Ham Sandwich"               370     35     24     15     10    20    20
  "Hamburger"                  500     42     25      6      2    25    20
  "Fish Sandwich"              370     38     14      2      0    15    10
  "Chicken Sandwich"           400     42     31      8     15    15     8
  "Fries"                      220     26      3      0     15     0     2
  "Sausage Biscuit"            345     27     15      4      0    20    15
  "Lowfat Milk"                110     12      9     10      4    30     0
  "Orange Juice"                80     20      1      2    120     2     2 ;

如何修复无模型错误？在test.py的第3行代码中定义了模型