Feel++ mo2fmu converter

Modelica to FMU converter with Dymola and OpenModelica support.

Features

• Multiple backends: Supports both Dymola and OpenModelica compilers
• Automatic backend selection: Automatically detects available compilers
• FMI 1.0, 2.0, and 3.0 support: Generate Co-Simulation and Model Exchange FMUs
• Python API: Programmatic access for integration into workflows
• Command-line interface: Simple CLI with compile and check subcommands

Installation

From PyPI (Recommended)

Install the latest stable release from PyPI using uv:

uv pip install feelpp-mo2fmu

With OpenModelica Support

To use OpenModelica as a backend, install with the optional dependency:

uv pip install "feelpp-mo2fmu[openmodelica]"

This will install OMPython for Python integration with OpenModelica.

With Simulation Support

To run simulations and validate FMUs (useful for testing):

uv pip install "feelpp-mo2fmu[simulation]"

This will install FMPy for FMU simulation and validation.

From Source

For development or to use the latest unreleased features:

git clone https://github.com/feelpp/mo2fmu.git
cd mo2fmu
uv venv .venv-mo2fmu
source .venv-mo2fmu/bin/activate  # On Windows: .venv-mo2fmu\Scripts\activate
uv pip install -e ".[all]"

Configuration

Dymola Location

The Dymola installation location can be configured via environment variables:

export DYMOLA_ROOT=/opt/dymola-2025xRefresh1-x86_64/
export DYMOLA_EXECUTABLE=/usr/local/bin/dymola
export DYMOLA_WHL=Modelica/Library/python_interface/dymola-2025.1-py3-none-any.whl

Environment Variables:

• DYMOLA_ROOT: Path to Dymola installation root directory (default: /opt/dymola-2025xRefresh1-x86_64/)
• DYMOLA_EXECUTABLE: Path to Dymola executable binary (default: /usr/local/bin/dymola)
• DYMOLA_WHL: Relative path to Dymola Python wheel from DYMOLA_ROOT (default: Modelica/Library/python_interface/dymola-2025.1-py3-none-any.whl)
• DYMOLA_STARTUP_RETRY_TIMEOUT: Time in seconds to wait for a shareable Dymola seat before failing (default: 0)
• DYMOLA_STARTUP_RETRY_INTERVAL: Delay in seconds between startup retries while waiting for a seat (default: 30)

OpenModelica Location

OpenModelica can be configured via environment variables:

export OPENMODELICA_HOME=/usr/lib/omc

Environment Variables:

• OPENMODELICA_HOME: Path to OpenModelica installation (default: auto-detected)

Command Line Interface

The mo2fmu CLI provides two subcommands: compile and check.

Main Help

$ mo2fmu --help
Usage: mo2fmu [OPTIONS] COMMAND [ARGS]...

  mo2fmu - Convert Modelica models to Functional Mock-up Units (FMUs).

  Use 'mo2fmu compile' to generate FMUs or 'mo2fmu check' to verify compilers.

Options:
  -v, --version  Show version information.
  --help         Show this message and exit.

Commands:
  check    Check availability of Modelica compilers and their FMI support.
  compile  Compile a Modelica model to FMU.

Compile Command

Generate FMUs from Modelica models:

$ mo2fmu compile --help
Usage: mo2fmu compile [OPTIONS] MO OUTDIR

  Compile a Modelica model to FMU.

Options:
  --name TEXT                     Custom name for the FMU (default: .mo file stem).
  -l, --load TEXT                 Load one or more Modelica packages.
  --flags TEXT                    Compiler-specific flags for FMU translation.
  -t, --type [all|cs|me|csSolver] FMI type: cs (Co-Simulation), me (Model Exchange),
                                  all, or csSolver.
  --fmi-version [1|2|3]           FMI version. FMI 3.0 requires Dymola 2024+
                                  or OpenModelica 1.21+.
  -b, --backend [dymola|openmodelica|auto]
                                  Modelica compiler backend (default: auto-detect).
  --dymola PATH                   Path to Dymola root directory.
  --dymola-exec PATH              Path to Dymola executable.
  --dymola-whl PATH               Path to Dymola wheel file (relative to Dymola root).
  -v, --verbose                   Enable verbose output.
  -f, --force                     Overwrite existing FMU.
  --help                          Show this message and exit.

Compile Examples:

# Basic compilation (auto-detect backend)
mo2fmu compile model.mo ./output

# Compile with OpenModelica backend
mo2fmu compile --backend openmodelica model.mo ./output

# Compile FMI 3.0 Co-Simulation FMU with verbose output
mo2fmu compile -v --fmi-version 3 --type cs model.mo ./output

# Force overwrite existing FMU
mo2fmu compile -f model.mo ./output

# Load additional Modelica packages
mo2fmu compile --load package1.mo --load package2.mo model.mo ./output

Check Command

Verify compiler availability and FMI support:

$ mo2fmu check --help
Usage: mo2fmu check [OPTIONS]

  Check availability of Modelica compilers and their FMI support.

Options:
  --dymola PATH       Path to Dymola root directory.
  --dymola-exec PATH  Path to Dymola executable.
  --dymola-whl PATH   Path to Dymola wheel file (relative to Dymola root).
  --json              Output results as JSON.
  --help              Show this message and exit.

Check Examples:

# Check all available compilers
mo2fmu check

# Output as JSON (for scripting)
mo2fmu check --json

# Check with custom Dymola path
mo2fmu check --dymola /opt/dymola-2024x

Python API

Recommended API

The recommended API provides a clean interface with automatic backend selection:

from feelpp.mo2fmu import CompilationRequest, checkCompilers, compileFmu, compileFmus, getCompiler

# Auto-detect and use available compiler
result = compileFmu("path/to/model.mo", "./output")
if result.success:
    print(f"FMU created at {result.fmu_path}")
else:
    print(f"Error: {result.error_message}")

# Explicitly use OpenModelica
result = compileFmu("path/to/model.mo", "./output", backend="openmodelica")

# Compile FMI 3.0 Model Exchange FMU
result = compileFmu(
    "path/to/model.mo",
    "./output",
    fmiType="me",
    fmiVersion="3",
    verbose=True,
)

# Check available compilers
available = checkCompilers()
for name, info in available.items():
    print(f"{name}: available={info['available']}, fmiSupport={info.get('fmiSupport', [])}")

# Get a specific compiler instance for more control
compiler = getCompiler("openmodelica")
if compiler.is_available:
    print(f"Using {compiler.name}")

# Batch compilation with one Dymola session
requests = [
    CompilationRequest(
        mo="path/to/model_a.mo",
        outdir="./output/a",
        fmu_model_name="ModelA",
        force=True,
    ),
    CompilationRequest(
        mo="path/to/model_b.mo",
        outdir="./output/b",
        fmu_model_name="ModelB",
        force=True,
    ),
]
results = compileFmus(requests, backend="dymola")

Using Compiler Classes Directly

For full control, use the compiler classes directly:

from feelpp.mo2fmu import (
    DymolaCompiler,
    OpenModelicaCompiler,
    ModelicaModel,
    CompilationConfig,
)
from pathlib import Path

# Using OpenModelica
compiler = OpenModelicaCompiler()
if compiler.is_available:
    model = ModelicaModel(Path("path/to/model.mo"))
    config = CompilationConfig(
        fmi_type="cs",      # Co-Simulation
        fmi_version="3",    # FMI 3.0
        verbose=True,
    )
    result = compiler.compile(model, Path("./output"), config)

    if result.success:
        print(f"FMU created: {result.fmu_path}")
    else:
        print(f"Compilation failed: {result.error_message}")

# Using Dymola
compiler = DymolaCompiler()
if compiler.is_available:
    result = compiler.compile(model, Path("./output"), config)

Legacy API

The original API is still available for backward compatibility:

from feelpp.mo2fmu import mo2fmu

mo2fmu(
    mo="path/to/model.mo",
    outdir="path/to/output/dir",
    fmumodelname="MyFMUModel",
    load=("Modelica", "SomePackage"),
    flags=("-d=initialization",),
    type="cs",
    version="2",
    dymola_root="/path/to/dymola/root",
    dymolapath="/path/to/dymola/executable",
    dymolawhl="path/to/dymola.whl",
    verbose=True,
    force=False,
    backend="dymola",  # or "openmodelica", "auto"
)

Backend Comparison

Feature	Dymola	OpenModelica
License	Commercial	Open Source (GPL)
FMI 1.0	✓	✓
FMI 2.0	✓	✓
FMI 3.0	✓ (2024+)	✓ (v1.21+)
Co-Simulation	✓	✓
Model Exchange	✓	✓
csSolver type	✓	✗
Modelica Standard Library	✓	✓
BuildingSystems	✓	Partial
Buildings Library	✓	✓

Running Tests

The test suite includes unit tests and FMU simulation tests:

# Run all tests
uv run pytest

# Run with verbose output
uv run pytest -v

# Run only unit tests (no simulation)
uv run pytest tests/test_compilers.py tests/test_mo2fmu.py

# Run simulation tests (requires FMPy)
uv run pytest tests/test_fmu_simulation.py

Continuous Integration

Our GitHub Actions workflow (.github/workflows/ci.yml) includes:

• build_wheel: code-quality checks, Python tests, wheel build, and artifact upload
• build_docs: Antora site build and GitHub Pages deployment on main
• release: on tags vX.Y.Z, downloads the built wheel, creates a GitHub release, and publishes to PyPI

Versioning & Release

The release being prepared is 1.0.0.

Release metadata is maintained in:

• pyproject.toml: Python package version
• CHANGELOG.md: release notes
• package.json and docs/antora.yml: documentation metadata

Documentation metadata under docs/ and package.json should be kept aligned when needed, but they are not the authoritative Python package version.

Release process:

1. Update pyproject.toml and CHANGELOG.md.
2. Push the release branch to GitHub.
3. Create and push a tag such as v1.0.0.
4. Let .github/workflows/ci.yml run the release job to publish the wheel to GitHub Releases and PyPI.

Contributing

We welcome contributions! Please:

• Fork the repository and create a feature branch.
• Adhere to existing coding conventions; add python tests where appropriate.
• Update documentation (docs/) for any new features.
• Submit a pull request with a clear description of your changes.

License

This project is licensed under the MIT License. See LICENSE for full details.