OpenMDAO hierarchical solvers recording

Question

In OpenMDAO, is there any recommendation on how to record and read solver cases if the model is composed of multiple groups/cycles, and multiple nonlinear solvers?

I have a model built of 2 cycles (cycle1 and cycle2), one of them containing two subcycles (cycle1_1 and cycle1_2). For now I am attaching a solver to each of my nonlinear solvers:

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)

When trying to read the results with:

cr = om.CaseReader(results)

I am getting the following error:

RuntimeError: Can't parse solver iteration coordinate: rank0:root._solve_nonlinear|0|NLRunOnce|0|cycle1._solve_nonlinear|0|NonlinearBlockGS|1|cycle1.cycle1_1._solve_nonlinear|1|NonlinearBlockGS|1

I am looking to get information about the convergence history and some plots on the coupling variables.

EDIT: My code has a structure similar to that in https://openmdao.org/newdocs/versions/latest/basic_user_guide/multidisciplinary_optimization/sellar.html, with the groups defined in setup:

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()

score 0 · Answer 1 · answered Feb 28 '22 at 23:51

Unfortunately, as of OpenMDAO V3.16 this looks like a bug. Its been logged as a high priority issue on the OpenMDAO development backlog: Issue #2453

I can replicate it with the following script:

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())

It seems to be the nested recorders that are triggering the bug. As a kind-of workaround you can stick the recorder on the lower level group/component instead. That will make it a bit harder to know which cases are from which solver iteration, but the naming scheme of the iteration coordinates should at least help a little there. Hopefully that gets you moving in the meantime, while the bug is fixed.

Thank you. My code has a structure similar to that in https://openmdao.org/newdocs/versions/latest/basic_user_guide/multidisciplinary_optimization/sellar.html, I define the groups and their components in setup. `cycle1_1_comp.add_recorder(recorder)` gives _NameError: name 'cycle1_1_comp' is not defined_. `model.cycle1.cycle1_1.cycle1_1_comp.add_recorder(recorder)` gives _AttributeError: 'Group' object has no attribute 'cycle1_1_comp'_. How do I reffer to such components? — Kasia, Mar 01 '22 at 09:35
You should look at my example code above more closely. I create those variables by assigning the return values of `add_subsystem` to them as I go. I can't be of more help than that without specific example run code — Justin Gray, Mar 01 '22 at 13:51
Please see the edit of the original question where a reproducible example is provided (I forgot to mention I edited it based on your answer). I am assigning the values of add_subsystem to cycle1_1_comp and cycle1_2_comp, if I understood your comment well. Despite that, these names appear not to be defined when running the model. Defining these variables inside setup or directly in the run script seem to make a difference. — Kasia, Mar 01 '22 at 14:07

OpenMDAO hierarchical solvers recording

1 Answers1

Linked