moo-sim-interface

moo-sim-interface is a Python package for the simulation of Modelica-based models, either as FMUs Functional Mock-up Units or using the OpenModelica or Dymola Python APIs. It allows for easily configurable simulation setup, execution and evaluation via a generic text-based interface. Its main purpose is parallelization of simulations and parameter sweeps. Furthermore, it provides a generic interface for Multi-Objective-Optimization.

Usage

The key idea is to provide a single configuration file in YAML format, which contains the necessary information to set up and run the simulations. To get started, it is recommended to copy one of the provided examples and adjust it to your needs.

The tool can be used either as a command line tool via:

run_sim -h to access the help menu and run_sim -f sim_config_file to run the simulations defined in the configuration file.

or as a python package by importing the module and calling the function:

from moo_sim_interface.simulator_api import run_simulations
run_simulations(sim_config_file)

When working with relative paths, configuration files and FMU files should be located in 'configs' and 'fmus' folders within your working directory.

Example

Here is an example of how to run a parameter sweep in parallel using a FMU model: Download the 'configs' and 'fmus' folders containing the examples and place them within your current working directory. Launch the simulations using the following command, which will output the results into a csv file:

run_sim -f pv_heat_example_config.yml

Installation

pip install git+https://github.com/SebastianMortag/moo-sim-interface.git

Requirements

• Python 3.10 or higher

• Numpy 2.2.0 or higher

• dask 2024.7.1 or higher

• PyYAML 6.0.0 or higher

• Plotly 5.15.0 or higher

• Matplotlib 3.7.0 or higher

• FMPy 0.3.22 or higher (for FMU simulations)

• OMPython 3.6.0 or higher (for OpenModelica simulations)

• Dymola 2022 or higher (for Dymola simulations)

Hints

OpenModelica FMU Export

Disable LOG Messages:

To prevent the solver CVode from printing log messages, set the Translation Flag --fmiFlags=none in OpenModelica->SimulationSetup->Translation Flags->Additional Translation Flags AND check Save translation flags inside model. Or add the Translation Flag for all Simulations via OpenModelica->Tools->Options->Simulation->Additional Translation Flags.

Disable stdout messages from CombiTimeTable by selecting CombiTimeTable->verboseRead: false

Configure FMI Settings:

Tools->Options->FMI

• Version: 2.0
• Typ: Co-Simulation
• Solver for Co-Simulation: CVODE
• • Include Modelica based resources via loadResource

Include Resources in the fmu:

In some cases, generating the fmu file fails when adding files as input resources. Go to OpenModelica->Tools->Options->General->Working Directory and choose a short path i.e. C:/OMEdit

Dymola FMU Export

Configure FMI Settings:

Simulation Setup->FMI Export

• Type: Co-simulation using Cvode
• Version: 2.0
• Options:
  • Copy resources to FMU
  • FMU needs no license key

Running FMUs requires access to the Runtime-Licence, this is not possible if the licence is managed by a DSLS Server. See chapter Limitations in the Dymola User Manual. In order to export FMUs with Dymola, which require no license key, your licence must allow for binary model export.

Parameter Evaluation:

Activate Evaluate parameters to reduce models in Simulation Setup->Translation This leads to the output of the model being fixed since parameters become constants, but simulation time is reduced. Can be used to simulate poorly parameterized models, since singularities at t=0 can occur when the initial values are not set correctly. This sets the flag Evaluate=false in the uses Annotations of the Modelica file. Parameters that are evaluated (symbolically) bevor the FMU is simulated, are marked as constant in the FMU. Their values con no longer be changed. To exclude specific parameters from the evaluation, add annotation (Evaluate=false) to the parameter declaration. If the declaration is in an unmodifiable submodule, propagate the parameter into a modifiable submodule and add the annotation there.

Maximum Simulation Run Time: (From Dymola User Manual 2B, p.22)

Go to Simulation Setup->General->Max simulation run time->Per simulation and specify the maximum (real) time in seconds that a simulation is allowed to run. If the simulation time exceeds this value, the simulation is aborted.

OpenModelica Scripting API

Disable LOG Messages:

Various options exist to disable log messages in OpenModelica.

Command Line Options (e.g. Compiler Flags for omc / Translation Flags in OMEdit):

• --demoMode Disable Info messages when loading a model. Warnings, like Lexer, are still displayed For example: ModelicaSystem(model_path, model_name, commandLineOptions='--demoMode')
• -q Silent mode, purpose unknown

Simulations Flags (C Runtime Simulation Flags):

• -lv=-LOG_SUCCESS Disable messages like "Simulation finished successfully" For example: model.simulate(simflags='-lv=-LOG_SUCCESS')
• -lv=-LOG_STDOUT Disable all messages written to stdout
• -lv=-LOG_ASSERT Disable all assert messages of type Info For OpenModelica v1.21 and below please use: -stdout and -assert

Planned Features

• Auto-remove OM/Dymola result files after successful simulations
• Select custom folders for OM/Dymola result files
• Run OM simulations in parallel (WiP)
• Inject LOG messages suppression into the simulation apis
• Implement safe mode for automatic simulation error handling for OM and Dymola
• Implement input and output parameter configuration using a csv file