Simulating System Dynamics Models in Python

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This project is a simple library for running System Dynamics models in Python, with the purpose of improving integration of Big Data and Machine Learning into the SD workflow.

PySD translates Vensim or XMILE model files into Python modules, and provides methods to modify, simulate, and observe those translated models. The translation is done throught an intermediate Abstract Synatax Tree representation, which makes it possible to add builders in other languages in a simpler way

Why create a new SD simulation engine?

There are a number of great SD programs out there (Vensim, iThink, AnyLogic, Insight Maker, and others). In order not to waste our effort, or fall victim to the Not-Invented-Here fallacy, we should have a very good reason for starting a new project.

That reason is this: There is a whole world of computational tools being developed in the larger data science community. System dynamicists should directly use the tools that other people are building, instead of replicating their functionality in SD specific software. The best way to do this is to bring specific SD functionality to the domain where those other tools are being developed.

This approach allows SD modelers to take advantage of the most recent developments in data science, and focus our efforts on improving the part of the stack that is unique to System Dynamics modeling.

Additional Resources

PySD Cookbook

A cookbook of simple recipes for advanced data analytics using PySD is available at:

The cookbook includes models, sample data, and code in the form of iPython notebooks that demonstrate a variety of data integration and analysis tasks. These models can be executed on your local machine, and modified to suit your particular analysis requirements.


The code for this package is available at:

If you find a bug, or are interested in a particular feature, see reporting bugs.

If you are interested in contributing to the development of PySD, see the developer documentation listed above.


If you use PySD in any published work, consider citing the PySD Introductory Paper:

Houghton, James; Siegel, Michael. "Advanced data analytics for system dynamics models using PySD." *Proceedings of the 33rd International Conference of the System Dynamics Society.* 2015.

You can also cite the library using the DOI provided by Zenodo. It is recomendable to specify the used PySD version and its correspondent DOI. If you want to cite all versions you can use the generic DOI for PySD instead:



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