dissmodel-sysdyn

System Dynamics models for dissmodel.

This library provides a collection of System Dynamics models implemented using the dissmodel core.

Installation

The package is not on PyPI. Install it from GitHub:

pip install git+https://github.com/DisSModel/dissmodel-sysdyn

or, from a clone, pip install . (pip install ".[examples]" for the Streamlit apps, pip install ".[dev]" for the tests).

Models

The library includes a wide range of System Dynamics models:

• Epidemiology: SIR Model.
• Ecology & Biology: Predator-Prey (Lotka-Volterra), Yeast Growth, Daisyworld, Population Growth, Limited Growth, Chaotic Growth.
• Physics & Thermodynamics: Coffee Cooling, Room Temperature, Tub (Stock/Flow).
• Complex Systems: Lorenz Attractor, Homeostasis.
• Environment: Mono Lake Water Balance.
• Stochasticity: Random Walk.

Verification against TerraME

Every model was run in TerraME 2.0.1 with the sysdyn package (terrame-goldens v0.1.0). For the 16 deterministic cases (13 models, some with two parameter sets), the Python models give the same doubles as TerraME at every step, bit for bit, for every variable TerraME records; RandomWalk is compared by distribution. tests/test_goldens.py runs these comparisons (pytest -m golden, under a second).

Examples

The project includes several examples demonstrating how to run the models via CLI, Streamlit, or Jupyter Notebooks.

CLI

To run a simple SIR model in the terminal:

python examples/cli/sysdyn_sir.py

Streamlit

To explore all available models using an interactive web interface:

streamlit run examples/streamlit/sysdyn_all.py

Notebooks (Educational)

We have developed a comprehensive suite of 14 educational notebooks designed for students and researchers. Each notebook functions as a self-contained tutorial, including scientific context, mathematical formulations, and guided experiments.

Located in examples/notebooks/:

• sysdyn_sir.ipynb - Epidemiological dynamics.
• sysdyn_predator_prey.ipynb - Predator-prey interactions.
• sysdyn_daisyworld.ipynb - Gaia hypothesis and albedo feedback.
• sysdyn_lorenz.ipynb - Deterministic chaos and strange attractors.
• sysdyn_chaotic_growth.ipynb - Logistic map and population chaos.
• sysdyn_yeast.ipynb - Logistic growth with carrying capacity.
• sysdyn_coffee.ipynb - Newton's Law of Cooling.
• sysdyn_mono_lake.ipynb - Ecological water balance.
• sysdyn_homeostasis.ipynb - Biological self-regulation.
• sysdyn_tub.ipynb - Fundamental stock and flow concepts.
• ... and more for every model in the library.

To run the notebooks:

jupyter notebook examples/notebooks/