News

30 August 2019: Packages are now available for Debian 10.x, Fedora 30, openSUSE Leap 15.1, and Ubuntu 19.04.
From the next release (5.2), there will be no more Mageia packages. If you use Mageia and would like assistance, please drop Ben an email.

31 May 2018: The knot tables are now live! You can download all 352,152,252 prime non-trivial knots with up to 19 crossings from Regina's data page.

21 December 2016: Regina 5.1 is out! This comes with a major overhaul for Python and C++ users. This follows version 5.0 from September, which added 4-manifolds, normal hypersurfaces, tree decompositions and more. Packages are available for MacOS, Windows and GNU/Linux, and there are also customised versions of Regina for the iPad and Sage. You can read more about what's new, or go ahead and download the new version.

15 November 2016: Regina has moved! It now lives at regina-normal.github.io. Please update your bookmarks accordingly.

17 October 2016: Mac users can now get Regina from the Mac App Store (for free, of course). There are minor differences between the App Store version and the direct download; see the download section for details.

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What is Regina?

For 3-manifolds, it includes high-level tasks such as 3-sphere recognition, connected sum decomposition and Hakenness testing, comes with a rich database of census manifolds, and incorporates the SnapPea kernel for working with hyperbolic manifolds. For 4-manifolds, it offers a range of combinatorial and algebraic tools, plus support for normal hypersurfaces.

Regina comes with a full graphical user interface, as well as Python bindings and a low-level C++ programming interface.

See the users' handbook for a detailed list of features.

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Screenshots

Studying 3-manifold triangulations	Normal surfaces and angle structures	In-built Python scripting

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Download

The following downloads are available:

Mac Windows GNU/Linux iPad Sage Source code

If you encounter any problems when you run Regina, you can check the troubleshooting page to see if your problem is discussed there. You also most welcome to contact us for help.

Mac

You have two options for Mac: either download direct from this website, or from the Mac App Store. If you're not sure, then try using the Mac App Store.

MacOS Version		Direct Download	Mac App Store
Mojave (10.14) High Sierra (10.13) Sierra (10.12) El Capitan (10.11) Yosemite (10.10) Mavericks (10.09)		Download from the Regina website

There are some minor differences between the two versions. The Mac App Store version:

• will notify you of upgrades automatically;
• may support iCloud in a future release (which is not possible for a direct download);
• is sandboxed, which limits file access through Python (see below).

Sandboxing is a security measure that comes with the Mac App Store: it ensures that apps only access files that users themselves choose through the MacOS graphical file dialogs (Open, Save, etc.). For Regina, this means that when you open a Python console through the graphical user interface, you cannot access arbitrary files using Python commands. If this causes you difficulties, then remember:

• you will always have full access to your Downloads folder, even through Python;
• you can always use the command-line regina-python tool instead.

Windows Version		Installer
Windows 10 Windows 8 Windows 7		Download

Notes for Windows:

• Windows 8 / 10 users might not be able to run the installer (“Windows SmartScreen prevented an unrecognized app from starting ...”). This is because Microsoft has not yet added Regina to its database of known applications. Click More info and you will be able to run the installer anyway.
• Windows 7 users might encounter a similar warning, for a similar reason (“Regina ... is not commonly downloaded and could harm your computer.”). Click Actions and you will be able to run the installer.

To keep the installation simple, most packages do not include the MPI (high-performance computing) utilities. If you need these, let Ben know and he can build you an MPI-enabled package.

Distribution		Version	32-bit package (i386 or i586)	64-bit package (amd64 or x86_64)
Debian		10.x (buster)	Install	Install
		9.x (stretch)	Install	Install
		8.x (jessie)	Install	Install
		unstable (sid)	Install	Install
Fedora		30	n/a	Download
		29	n/a	Download
		28	n/a	Download
		27	n/a	Download
		26	n/a	Download
		25	Download	Download
		24	Download	Download
Mageia		5	Download	Download
openSUSE		Leap 15.1	n/a	Download Read first
		Leap 15.0	n/a	Download Read first
		Leap 42.3	n/a	Download
		Leap 42.2	n/a	Download
		Leap 42.1	n/a	Download
Ubuntu		19.04 (disco)	n/a	Install
		18.10 (cosmic)	n/a	Install
		18.04 LTS (bionic)	n/a	Install
		17.10 (artful)	n/a	Install
		17.04 (zesty)	Install	Install
		16.10 (yakkety)	Install	Install
		16.04 LTS (xenial)	Install	Install

For older versions of GNU/Linux:

• If your distribution is in the table above but your version is too old, then your version of GNU/Linux may have passed its end-of-life. This is a security risk, since most distributions do not provide security updates for old (end-of-life) versions. You should seriously consider upgrading your machine.

For newer versions of GNU/Linux:

• If your distribution is in the table above but your version is too new, then drop Ben an email and he should be able to upload a package for you. Otherwise you can always build from source (see below).

For other GNU/Linux distributions:

• If you are using some other distribution (e.g., RedHat, Slackware, …), then you will need to build Regina from source.

iOS Version	Installer
iOS 8 and above

Sage Version		Installer
Any		Instructions

Of course, whilst the packages are written to work with any modern version of Sage, your experiences might vary (particular with an older Sage and/or operating system). Follow the instructions link above for details.

Source code

For other systems not listed above, you will need to build Regina from its source code.

You can download the source code here.

Please see the separate page on building Regina for instructions on how to build Regina and what libraries and tools you will need to have installed.

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Documentation

Users' Handbook

You can read the handbook from within Regina by selecting Help → Regina Handbook from the menu. You can also read it here online.

Python/C++ API Documentation

You can read the API documentation by selecting Help → Python API Reference from the menu. You can also read it here online.

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What's new in version 5.1?

• Regina 5.0, which introduced many new mathematical features;
• Regina 5.1, which made significant changes to the Python / C++ interface.

Version 5.1 (December 2016)

Python and C++

• All of the code that was deprecated in version 5.0 has now been removed entirely. See the page on moving from 4.x to 5.x for instructions on how to update your scripts.
• Many class and header names have changed, but most of these changes follow a standard pattern (classes of the form NFoo become Foo, and headers of the form nfoo.h become foo.h). The old class and header names have been kept, and will not be removed until Regina 6.0. See the page on moving from 5.x to 6.x for details.
• More of Regina's triangulation code is now generic, which means you can do more with higher-dimensional triangulations (e.g., triangulate boundary components, or compute homology).
• The old “python libraries” facility has been removed, since Python itself offers better and more standardised ways of importing code.

Version 5.0 (September 2016)

Features

• Regina now works with 4-manifolds! It also offers a more basic framework for triangulations in higher dimensions (up to 15).
• You can now enumerate, study and triangulate normal hypersurfaces in 4-manifold triangulations.
• Regina now builds and manipulates tree decompositions of graphs, including dual graphs of triangulations. This is particularly useful for fixed-parameter tractable algorithms.
• Turaev-Viro invariants are now computed using exact arithmetic.
• When fast-and-greedy simplification fails, you can now try “exhaustive simplification”, which searches through the Pachner graph.

Python and C++

• The API (functions, classes, etc.) has had an enormous overhaul. Many things are now simpler, shorter, and more consistent. Most of the old classes and functions have been kept for backward compatibility, but will be removed in the next release.
• Regina is now based on the newer C++11 standard.
• Python now interacts with Regina more naturally, and error messages are likely to be both fewer and more helpful. Thanks to Matthias Goerner for his help with this.
• Regina no longer clobbers Python's own builtin open() function! For Regina's verison of open(), you can still call regina.open().

Optimisations

• Many widespread structural changes under the hood.
• Several new optimisations, most notably including treewidth-based algorithms for Turaev-Viro invariants (arXiv:1503.04099).

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Announcement Mailing List

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License and Citation

Many others have been of assistance with this project, be it through time, knowledge, testing or code. Please see the full list of acknowledgements in the users' handbook.

Citation

Benjamin A. Burton, Ryan Budney, William Pettersson, et al.,
Regina: Software for low-dimensional topology,
http://regina-normal.github.io/, 1999–2017.

@misc{regina,
    author = {Benjamin A. Burton and Ryan Budney and William Pettersson and others},
    title = {Regina: Software for low-dimensional topology},
    howpublished = {{\tt http://\allowbreak regina-normal.\allowbreak github.\allowbreak io/}},
    year = {1999--2017}}

Copying & modification

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

Some of this code comes with additional permissions, which allow it to be distributed through online repositories such as Apple's App Store or Google Play. See the full license in the users' handbook for details.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.

Detailed License

For complete license details, including the full GNU General Public License and information on external software that Regina uses, see the full license in the users' handbook.

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Contact

If you have written your own extensions that you think could be worth putting in the main release, please do write and let us know.

Even if you have no comments to make, it's always nice to hear from people using Regina, even if it's just to say hi. We're always interested to hear how this software is being used.

You can contact us by email: our websites are linked to our names in the author list above.

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