

Stan is based on a probabilistic programming language for specifying models in terms of probability distributions. Stan's modeling language is is portable across all interfaces (PyStan, RStan, CmdStan).
The modeling language manual is released under the most accomodating of the Creative Commons licenses,CC BY (v3)
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The modeling language manual contains a guide to programming in Stan with example models, a reference manual for the language itself, and a reference guide to the built-in special functions and probability functions.