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--generateSymbolicLinearization causes error for some models #274
Description
Description
Current implementation of ModelicaSystem sets --generateSymbolicLinearization in __init__, regardless of whether the user actually wants to perform linearization. This causes an error for some models, e.g. this one:
model.mo:
model MyModel
Modelica.Clocked.RealSignals.Sampler.SampleClocked sample1 annotation(
Placement(transformation(origin = {-40, 40}, extent = {{-6, -6}, {6, 6}})));
Modelica.Clocked.RealSignals.Sampler.Hold hold1 annotation(
Placement(transformation(origin = {20, 40}, extent = {{-6, -6}, {6, 6}})));
Modelica.Clocked.ClockSignals.Clocks.PeriodicRealClock periodicClock1(period = 0.1) annotation(
Placement(transformation(origin = {-80, 0}, extent = {{-6, -6}, {6, 6}})));
Modelica.Blocks.Interfaces.RealInput u annotation(
Placement(transformation(origin = {-86, 40}, extent = {{-20, -20}, {20, 20}}), iconTransformation(origin = {-86, 30}, extent = {{-20, -20}, {20, 20}})));
Modelica.Clocked.RealSignals.Periodic.TransferFunction transferFunction(b = {1}, a = {1, -1}) annotation(
Placement(transformation(origin = {-12, 40}, extent = {{-10, -10}, {10, 10}})));
Modelica.Blocks.Interfaces.RealOutput y annotation(
Placement(transformation(origin = {60, 40}, extent = {{-10, -10}, {10, 10}}), iconTransformation(origin = {60, 40}, extent = {{-10, -10}, {10, 10}})));
equation
connect(periodicClock1.y, sample1.clock) annotation(
Line(points = {{-74, 0}, {-40, 0}, {-40, 32}}, color = {175, 175, 175}));
connect(u, sample1.u) annotation(
Line(points = {{-86, 40}, {-48, 40}}, color = {0, 0, 127}));
connect(sample1.y, transferFunction.u) annotation(
Line(points = {{-34, 40}, {-24, 40}}, color = {0, 0, 127}));
connect(transferFunction.y, hold1.u) annotation(
Line(points = {{0, 40}, {12, 40}}, color = {0, 0, 127}));
connect(y, hold1.y) annotation(
Line(points = {{60, 40}, {26, 40}}, color = {0, 0, 127}));
annotation(
uses(Modelica(version = "4.0.0")));
end MyModel;with demo.py:
#!/usr/bin/env python3
from OMPython import ModelicaSystem
# note the raiseerrors=True
mod = ModelicaSystem("model.mo", "MyModel", ["Modelica"], raiseerrors=True)
# this should be enough to demonstrate the errorRunning demo.py results in the following exception:
Traceback (most recent call last):
File "/home/ondra/tmp/lin-demo/./demo.py", line 4, in <module>
mod = ModelicaSystem("model.mo", "MyModel", ["Modelica"], raiseerrors=True)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/ondra/source/repos/OMPython/OMPython/ModelicaSystem.py", line 228, in __init__
self.buildModel(variableFilter)
File "/home/ondra/source/repos/OMPython/OMPython/ModelicaSystem.py", line 352, in buildModel
self._check_error()
File "/home/ondra/source/repos/OMPython/OMPython/ModelicaSystem.py", line 332, in _check_error
self._raise_error(errstr=errstr)
File "/home/ondra/source/repos/OMPython/OMPython/ModelicaSystem.py", line 336, in _raise_error
raise ModelicaSystemError(f"OM error: {errstr}")
OMPython.ModelicaSystem.ModelicaSystemError: OM error: [/var/lib/jenkins/ws/LINUX_BUILDS/tmp.build/openmodelica-1.25.0/OMCompiler/Compiler/BackEnd/Differentiate.mo:268:5-268:157:writable] Error: Derivative of expression "transferFunction.x1 = (transferFunction.u - transferFunction.a[2] * previous(transferFunction.x[1])) / transferFunction.a[1]" w.r.t. "dummyVarD" is non-existent.
Error: Internal error SymbolicJacobian.deriveAll failed
[/var/lib/jenkins/ws/LINUX_BUILDS/tmp.build/openmodelica-1.25.0/OMCompiler/Compiler/BackEnd/SymbolicJacobian.mo:2474:7-2474:74:writable] Error: Internal error SymbolicJacobian.generateSymbolicJacobian failed
[/var/lib/jenkins/ws/LINUX_BUILDS/tmp.build/openmodelica-1.25.0/OMCompiler/Compiler/BackEnd/SymbolicJacobian.mo:2265:9-2265:79:writable] Error: Internal error function createJacobian failed
Ideally, it should be possible to simulate this model while keeping raiseerrors=True.
Version and OS
- Python Version: 3.12.3
- OMPython Version: 0b63a2b
- OpenModelica Version: 1.25.0
- OS: Ubuntu 24.04.2 LTS
Activity
arun3688 commentedon Jun 17, 2025
@ondras12345 that is true, current ModelicaSystem sets
--generateSymbolicLinearization, it is done to improve the performance of linearization to avoid recompilation, eventhough user does not want to perform linearization, but then there are cases where users wants to perform the linearization in some kind of simulation loop and that takes too much time to compile the model. So one solution should would be to set the--generateSymbolicLinearizationusing some args inModelicaSystem( linearization = true), by default the argument can belinearization = false, but in general it should work may be it is a bug in the backend@adeas31 what do you think
syntron commentedon Aug 23, 2025
It would be possible to link this with the option
commandLineOptions- if it is set toNonedefault values are used (currently:--linearizationDumpLanguage=pythonand--generateSymbolicLinearization), else the user has to define the options he would like to use ...In that case, I propose to change it from
strto alistof options ...syntron commentedon Sep 19, 2025
@ondras12345 could you test using PR #349? it should work if you set
commandLineOptions=[]adeas31 commentedon Sep 19, 2025
#349 is now merged.
ondras12345 commentedon Sep 19, 2025
No more errors with
commandLineOptions=[]. Thanks!