Pyomo 更新 Set 和 Var 再次解决

Question

我对 Pyomo 很陌生，但对 Python 不熟悉。

我有以下问题：

import pyomo.environ as pyo

model = pyo.ConcreteModel()
model.A = pyo.Set(initialize=range(7))
model.B = pyo.Set(initialize=range(7))
model.AB = pyo.Set(initilize= list((a,b) for a in model.A for b in model.B)
model.X = pyo.Var(model.A, model.B, within=pyo.Binary)
model.objective = pyo.Objective(... maximize)
solver = pyo.SolverFactory('glpk')
result = solver.solve(model)

接下来我想更新 model.B Set() 并修改 de model.AB Set 和 model.X Var，这样我就可以再次解决它。比如我想设置：

model.B = pyo.Set(initialize=range(4)

然后更新model.AB、model.X并再次求解。如果手动完成：

model.B = pyo.Set(initialize=range(4)
model.AB = pyo.Set(initilize= list((a,b) for a in model.A for b in model.B)
model.X = pyo.Var(model.A, model.B, within=pyo.Binary)
result = solver.solve(model)

这不起作用，它给出了以下错误：

RuntimeError: Cannot add component 'X_index' (type <class 'pyomo.core.base.sets._SetProduct'>) to block 'unknown': a component by that name (type <class 'pyomo.core.base.sets._SetProduct'>) is already defined.

Answer 1

基本上，您需要先删除变量及其索引，然后再重新创建它。套装也是如此。

因此，本质上，您需要在重新定义新组件之前添加以下几行：

model.del_component(model.B)
model.del_component(model.AB)
model.del_component(model.X)
model.del_component(model.X_index)

然后你可以继续重新定义它们：

model.B = pyo.Set(initialize=range(4)
model.AB = pyo.Set(initialize= list((a,b) for a in model.A for b in model.B))
model.X = pyo.Var(model.A, model.B, within=pyo.Binary)