将 variables/constraints 添加到 Gurobi 持久性时出现 AttributeErrors

Question

我正在尝试通过添加 variables/constraints 修改模型并重新求解更新后的模型，遵循 the guide。

问题是这两种情况都因属性错误而失败，对于变量：

Traceback (most recent call last):
  File "seqdesign.py", line 98, in <module>
    main()
  File "seqdesign.py", line 71, in main
    problem._solver.add_var(problem._model.McBernoulliTrials)
  File "/home/edo/miniconda3/envs/spacers/lib/python3.7/site-packages/pyomo/solvers/plugins/solvers/persistent_solver.py", line 153, in add_var
    self._add_var(var)
  File "/home/edo/miniconda3/envs/spacers/lib/python3.7/site-packages/pyomo/solvers/plugins/solvers/gurobi_direct.py", line 208, in _add_var
    vtype = self._gurobi_vtype_from_var(var)
  File "/home/edo/miniconda3/envs/spacers/lib/python3.7/site-packages/pyomo/solvers/plugins/solvers/gurobi_direct.py", line 377, in _gurobi_vtype_from_var
    if var.is_binary():
AttributeError: 'IndexedVar' object has no attribute 'is_binary'

对于约束：

Traceback (most recent call last):
  File "seqdesign.py", line 98, in <module>
    main()
  File "seqdesign.py", line 71, in main
    problem._solver.add_constraint(problem._model.McBernoulliTrialsSetPositive)
  File "/home/edo/miniconda3/envs/spacers/lib/python3.7/site-packages/pyomo/solvers/plugins/solvers/persistent_solver.py", line 132, in add_constraint
    self._add_constraint(con)
  File "/home/edo/miniconda3/envs/spacers/lib/python3.7/site-packages/pyomo/solvers/plugins/solvers/gurobi_direct.py", line 272, in _add_constraint
    if is_fixed(con.body):
AttributeError: 'IndexedConstraint' object has no attribute 'body'

是我使用索引变量和约束的问题吗？如何在不将所有代码从 pyomo.environ 迁移到 pyomo.core 的情况下完成这项工作？

Answer 1

您不能将 IndexedVar 或 IndexedConstraint 传递给 add_var 和 add_constraint 方法。您必须遍历各个变量和约束并一次添加一个：

for v in my_var.values():
    solver.add_var(v)

for c in my_con.values():
    solver.add_constraint(c)

此外，您可以检查变量或约束是否使用 my_var.is_indexed() 或 my_con.is_indexed() 进行索引。

将 variables/constraints 添加到 Gurobi 持久性时出现 AttributeErrors

AttributeErrors when adding variables/constraints to Gurobi persistent

python

attributeerror

pyomo