\label{sec:summary} In this paper we have presented the first public release of gadfly. We have described the frameworkâs structure, which is designed around three core abstractions: the PartType dataframe (Section \ref{sec:df}), the Snapshot object (Section \ref{sec:snap}), and the Simulation object (Section \ref{sec:sim}). Additional functionality includes intelligent memory management and file access (Section \ref{sec:fileIO}), basic unit handling (Section \ref{sec:units}), coordinate transformations (Section \ref{sec:coords}), utilities for parallel batch processing (Section \ref{sec:parallel}), and SPH particle visualization (Section \ref{sec:vis}).
Gadfly is fully open-source, is released under the MIT License, and can be downloaded and installed from its repository at http://github.com/hummel/gadfly. Users can submit bug reports via GitHub, and if they know how to fix them, are welcome to submit pull requests.