# SnapPy

## What is SnapPy?

SnapPy is a program for studying the topology and geometry of 3-manifolds, with a focus on hyperbolic structures. It runs on Mac OS X, Linux, and Windows, and combines a link editor and 3D-graphics for Dirichlet domains and cusp neighborhoods with a powerful command-line interface based on the Python programming language. You can see it in action, learn how to install it, and watch the tutorial.

## News

- Version 2.3 (March 2015): New features include:
  - Major improvements to the link and planar diagram component, including link simplification, random links, and better documentation.
  - Basic support for spun normal surfaces.
  - New extra features when used inside of Sage:
    - HIKMOT-style rigorous verification of hyperbolic structures, contributed by Matthias Goerner.
    - Many basic knot/link invariants, contributed by Robert Lipschitz and Jennet Dickinson.
    - Sage-specific functions are now more easily accessible as methods of Manifold and better documented.
    - Improved number field recognition, thanks to Matthias.
  - Better compatibility with OS X Yosemite and Windows 8.1.
  - Development changes:
    - Major source code reorganization/cleanup.
    - Source code repository moved to Bitbucket.
    - Python modules now hosted on PyPI, simplifying installation.
- Complete version history.

## Documention

- Installing SnapPy
- Screenshots: SnapPy in action
- Tutorial
- The snappy module and its classes
- Using SnapPy’s link editor
- Links: planar diagrams and invariants
- Number theory of hyperbolic 3-manifolds
- Verified computations
- Other components
- News
- Credits
- To Do List
- Development Basics

## Credits

Written by Marc Culler and Nathan Dunfield using the SnapPea kernel written by Jeff Weeks, with contributions from many others. If you use SnapPy in your work, please cite it as described here.

Released under the terms of the GNU General Public License, version 2 or later.

The development of SnapPy was partially supported by grants from the National Science Foundation, including DMS-0906155 and DMS-0707136. Any opinions, findings, and conclusions or recommendations expressed on this site are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.