为什么总是从 RangeSet 到 Pyomo 中的约束使用默认值？

Question

我无法为 RangeSet 的最后一个值提供 i+1 值，因此我想在约束中忽略它。但是，我无法这样做，因为 i 值始终作为默认值。所以，它不会进入if语句。我该如何解决这个问题？

import pyomo.environ as pyo
from pyomo.opt import SolverFactory

model = pyo.AbstractModel()

number_of_lane=2
number_of_vehicle=2

model.i = pyo.Param(within=pyo.NonNegativeIntegers, default=number_of_lane)
model.j = pyo.Param(within=pyo.NonNegativeIntegers, default=number_of_vehicle)

model.I = pyo.RangeSet(1, model.i)
model.J = pyo.RangeSet(1, model.j)

model.R = pyo.Param(default=0.5) #CAV's reaction (s)
model.D = pyo.Param(default=1.5) #Safety Distance (m)
model.lv = pyo.Param(default=4) #Length of vehicle (m)

model.xr = pyo.Param(model.I, model.J, within=pyo.NonNegativeIntegers, initialize=xr_cons)
model.x = pyo.Var(model.I, model.J, domain=pyo.NonNegativeReals, initialize=(0))

def lane_crossing_constraint_rule(m, i, j): #lane should be 2, vehicles will be the first one which is close to the intersection
    m.i.pprint() #There is a problem about taking i and j value
    if(m.i.value<number_of_vehicle): #Always comes equal!!!!
        return (m.x[i,j]-m.xr[i,j])**2+(m.x[i+1,j]-m.xr[i+1,j])**2>=(m.lv+m.D)
    else:
        return pyo.Constraint.Skip

# the next line creates one constraint for each member of the set model.I
model.l1Constraint = pyo.Constraint(model.I, model.J, rule=lane_crossing_constraint_rule)

Answer 1

目前还不清楚您要尝试使用您选择的模型设置做什么。为什么选择

AbstractModel()

？您的示例不可重现，因为它缺少数据并且您没有构建模型实例。此外，我不确定您想通过从参数值初始化范围集大小来实现什么目的？

我认为你应该从

ConcreteModel()

开始，让一些东西发挥作用，并在需要时从那里开始构建。一次构建一点点，打印模型并验证它，然后添加到其中。

这是一个小例子，我认为它展示了您正在尝试做的一些事情。它是一个

ConcreteModel

，用于构建范围集、变量，并展示如何创建依赖于集合中索引值的约束

Lanes

import pyomo.environ as pyo
from pyomo.opt import SolverFactory

model = pyo.ConcreteModel()

number_of_lanes = 5

model.Lanes = pyo.RangeSet(1, number_of_lanes)

model.car_speed = pyo.Var(model.Lanes, domain=pyo.NonNegativeReals)


def lane_speed(model, lane):
    if lane < 4:
        return model.car_speed[lane] <= 60
    return pyo.Constraint.Skip


model.lane_speed = pyo.Constraint(model.Lanes, rule=lane_speed)

model.pprint()

输出

1 RangeSet Declarations
    Lanes : Dimen=1, Size=5, Bounds=(1, 5)
        Key  : Finite : Members
        None :   True :   [1:5]

1 Var Declarations
    car_speed : Size=5, Index=Lanes
        Key : Lower : Value : Upper : Fixed : Stale : Domain
          1 :     0 :  None :  None : False :  True : NonNegativeReals
          2 :     0 :  None :  None : False :  True : NonNegativeReals
          3 :     0 :  None :  None : False :  True : NonNegativeReals
          4 :     0 :  None :  None : False :  True : NonNegativeReals
          5 :     0 :  None :  None : False :  True : NonNegativeReals

1 Constraint Declarations
    lane_speed : Size=3, Index=Lanes, Active=True
        Key : Lower : Body         : Upper : Active
          1 :  -Inf : car_speed[1] :  60.0 :   True
          2 :  -Inf : car_speed[2] :  60.0 :   True
          3 :  -Inf : car_speed[3] :  60.0 :   True

3 Declarations: Lanes car_speed lane_speed