OpenMDAO 分层求解器记录

Question

在OpenMDAO中，如果模型由多个组/循环和多个非线性求解器组成，是否有关于如何记录和读取求解器案例的建议？

我有一个由 2 个周期（周期 1 和周期 2）构建的模型，其中一个包含两个子周期（周期 1_1 和周期 1_2）。现在，我将一个求解器附加到每个非线性求解器：

solver1 = model.cycle1.nonlinear_solver
solver1_1 = model.cycle1.cycle1_1.nonlinear_solver
solver1_2 = model.cycle1.cycle1_2.nonlinear_solver
solver2 = model.cycle2.nonlinear_solver

solver1.add_recorder(recorder)
solver1_1.add_recorder(recorder)
solver1_2.add_recorder(recorder)
solver2.add_recorder(recorder)

当尝试使用以下命令读取结果时：

cr = om.CaseReader(results)

我收到以下错误：

运行时错误：无法解析求解器迭代坐标： rank0:root._solve_nonlinear|0|NLRunOnce|0|cycle1._solve_nonlinear|0|NonlinearBlockGS|1|cycle1.cycle1_1._solve_nonlinear|1|NonlinearBlockGS|1

我希望获取有关收敛历史和耦合变量上的一些图的信息。

编辑：我的代码的结构类似于 https://openmdao .org/newdocs/versions/latest/basic_user_guide/multisubject_optimization/sellar.html，其中组在设置中定义：

import openmdao.api as om

class MDA(om.Group):
    
    # class ObjCmp(om.ExplicitComponent):
        # some objective component
    # class ConCmp(om.ExplicitComponent):
        # some constraint component
    
    def setup(self):
        
        cycle1 = self.add_subsystem('cycle1', om.Group(), promotes=['*'])
        
        cycle1_1 = cycle1.add_subsystem('cycle1_1', om.Group(), promotes=['*'])
        cycle1_1_comp = cycle1_1.add_subsystem('comp', om.ExecComp('x1 = 3 + x2'), promotes=["*"])

        cycle1_2 = cycle1.add_subsystem('cycle1_2', om.Group(), promotes=['*'])
        cycle1_2_comp = cycle1_2.add_subsystem('comp',  om.ExecComp('x2 = 3 + x1 + y'), promotes=["*"])

        cycle2 = self.add_subsystem('cycle2', om.Group(), promotes=['*'])
        cycle2.add_subsystem('comp', om.ExecComp('y = x1 + 2'), promotes=['*'])

p = om.Problem(model=MDA())
model = p.model

p.setup()

p.run_model()

Answer 1

不幸的是，从 OpenMDAO V3.16 开始，这看起来像是一个错误。它已被记录为 OpenMDAO 开发待办事项中的一个高优先级问题：Issue #2453

I可以使用以下脚本复制它：

import openmdao.api as om

p = om.Problem()

model = p.model

cycle1 = p.model.add_subsystem('cycle1', om.Group(), promotes=['*'])
cycle1_1 = cycle1.add_subsystem('cycle1_1', om.Group(), promotes=['*'])
cycle1_1_comp = cycle1_1.add_subsystem('comp', om.ExecComp('x1 = 3 + x2'), promotes=["*"])

cycle1_2 = cycle1.add_subsystem('cycle1_2', om.Group(), promotes=['*'])
cycle1_2_comp = cycle1_2.add_subsystem('comp',  om.ExecComp('x2 = 3 + x1 + y'), promotes=["*"])

cycle2 = p.model.add_subsystem('cycle2', om.Group(), promotes=['*'])
cycle2.add_subsystem('comp', om.ExecComp('y = x1 + 2'), promotes=['*'])


solver1 = model.cycle1.nonlinear_solver
solver1_1 = model.cycle1.cycle1_1.nonlinear_solver
solver1_2 = model.cycle1.cycle1_2.nonlinear_solver
solver2 = model.cycle2.nonlinear_solver

print(solver1, solver1_1, solver1_2, solver2)

recorder = om.SqliteRecorder('cases.db')

solver1.add_recorder(recorder)

# recorders on nested solvers trigger the bug 
# solver1_1.add_recorder(recorder)
# solver1_2.add_recorder(recorder)

# Kind-of workaround, put the recorder on the child component/group instead
cycle1_1_comp.add_recorder(recorder)
cycle1_2_comp.add_recorder(recorder)

solver2.add_recorder(recorder)

p.setup()

p.run_model()


reader = om.CaseReader('cases.db')

print(reader.list_sources())

似乎是嵌套记录器触发了该错误。作为一种解决方法，您可以将记录器粘贴到较低级别的组/组件上。这将使了解哪些情况来自哪个求解器迭代变得有点困难，但迭代坐标的命名方案至少应该有一点帮助。希望这能让您在修复错误的同时继续前进。