jneqsim 3.12.1

Python bindings for the Java library NeqSim (via JPype), with python stubs

jNeqSim

Python interface for the NeqSim java package, with stubs. Java interface is created with jpype, and stubs are generated with stubgenj

PYPI

https://pypi.org/project/jneqsim/

[!NOTE] JNeqSim mirrors NeqSims versions

Demo

Example

from jneqsim import neqsim


def pressurize_gas():
    inlet_fluid = neqsim.thermo.system.SystemSrkEos()
    neqsim.thermo.system.SystemSrkEos()
    thermo_ops = neqsim.thermodynamicOperations.ThermodynamicOperations(inlet_fluid)
    inlet_fluid.addComponent("methane", 100.0)

    inlet_fluid.setTemperature(10, "C")
    inlet_fluid.setPressure(20, "bara")
    inlet_fluid.setMultiPhaseCheck(True)
    inlet_fluid.setSolidPhaseCheck("methane")

    thermo_ops.TPflash()
    thermo_ops.bubblePointTemperatureFlash()

    inlet_fluid.initProperties()
    enthalpy = inlet_fluid.getEnthalpy()

    inlet_fluid.setPressure(1.0, "bara")
    thermo_ops.PHflash(enthalpy)

Dependencies

• jpype

Version Management

jneqsim uses a controlled release process to ensure compatibility:

• Pinned Versions: Each jneqsim release is pinned to a specific, tested NeqSim JAR version
• Automated Updates: The nightly CI workflow automatically checks for new NeqSim releases and publishes updated jneqsim packages when available
• No Auto-Updates: Applications using jneqsim will not automatically download newer NeqSim versions - they use the tested version that comes with their installed jneqsim package
• Cache Management: Downloaded JARs are cached locally in ~/.jneqsim/cache for faster subsequent usage

Development

Running Tests

The project uses pytest with custom markers to categorize tests. Test dependencies are already included in the development dependencies.

# Install development dependencies (includes pytest and pytest-mock)
poetry install

# Run unit tests (fast, excludes tests marked as slow)
pytest -v -m "not slow" tests/

# Run all tests (may download JARs for integration tests)
pytest -v tests/

# Run with coverage (requires pytest-cov)
poetry add --group dev pytest-cov
poetry run pytest --cov=jneqsim --cov-report=html tests/

Test markers:

• slow: Tests that may download files or take longer to run
• integration: Integration tests that require external dependencies
• unit: Fast unit tests (default)

:+1: Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.