AI-assisted article. Sources checked October 9, 2026. Examples are illustrative.
Ptolemy II is a software framework from the Ptolemy Project at the University of California, Berkeley. The project's documentation describes actor-oriented modeling and models of computation, including dataflow, discrete events, and continuous-time systems. Directors define the execution semantics of a model. Ptolemy II project page.
Why execution rules belong in the explanation
When two diagrams contain similar-looking components, it is tempting to assume they describe the same behavior. A model review should also ask how those components communicate, when they execute, and how time is represented. The modeling framework's rules matter alongside the boxes and connecting lines.
For a reader evaluating an example, first identify its director and intended model of computation. Then identify the input, expected output, and assumptions. Do not call a diagram a validated simulation merely because it can be opened in a modeling environment.
A small evaluation notebook
An illustrative evaluation starts with an official example rather than an invented production scenario. Record the version, example name, input settings, observed output, and any warning. Make one documented change and describe the resulting difference. If you cannot reproduce the baseline, keep that failure visible before interpreting a modified result.
The notebook should distinguish a software execution error from a disagreement between a model and the real-world system it is meant to represent. A successful run addresses the former; it does not automatically resolve the latter.
Scope of this article
This is a source-grounded introduction to the Berkeley software project. It is not a report that Apiary uses Ptolemy II, a benchmark of its performance, or a description of a similarly named physics experiment. The primary project documentation is the correct place to follow installation and example-specific instructions.