Same simulation settings in GUI and Python script

[AnHeuermann]

We'd like to test some OpenModelica FMUs with different FMU Importing tools and noticed, that FMPy is very slow (doesn't finish) in simulating a FMU from the Modelica Buildings library when using the GUI.
Trying to reproduce the issue with a Python script failed (it simulated fast), so I guess I only need to change some settings in the GUI of FMPy, but I don't know which one.

How to reproduce

Build the 2.0 ModelExchange FMU with OpenModelica by running the following MOS script

build.mos

loadModel(Modelica, {"4.0.0"}); getErrorString();
loadModel(Buildings, {"10"}); getErrorString();

cd("CO2TransportStep"); getErrorString();
buildModelFMU(Buildings.Airflow.Multizone.Examples.CO2TransportStep); getErrorString();

mkdir CO2TransportStep
omc build.mos

or download Buildings.Airflow.Multizone.Examples.CO2TransportStep.fmu (Linux) and change .zip to .fmu.

Simulating with the GUI:

Takes forever. I stopped the simulation after several minutes and reaching not even 2 percent.

Simulating via command line:

time fmpy simulate CO2TransportStep/Buildings.Airflow.Multizone.Examples.CO2TransportStep.fmu
fmpy simulate   0.71s user 1.28s system 1061% cpu 0.188 total

Simulation via Python Script:

from fmpy import *
fmu = 'CO2TransportStep/Buildings.Airflow.Multizone.Examples.CO2TransportStep.fmu'
result = simulate_fmu(
  fmu,
  solver = 'CVode')

python3 runFMPy.py  0.55s user 1.38s system 991% cpu 0.195 total

Versions 'n Stuff

• Python: 3.10.12
• FMPy: 0.3.19
• OS: WSL2 with Ubuntu Focal

[t-sommer]

Does the problem still exist? If so, can you please share a Windows version of the FMU?