Troubleshooting and FAQ

If you use GNU/Linux, look for Regina in your applications menu (for instance, the main GNOME or KDE menu). It might be classified under Science or Education. If all else fails, you can always start Regina from the command line by running regina-gui.

If you use macOS, you should have downloaded a drag-and-drop app bundle. You can start Regina simply by opening this app from wherever you dragged it to (typically the Applications folder).

If you use Windows, you can find Regina in the Start menu. Look for All Programs→Regina 7.3→Regina.

If you downloaded a GNU/Linux package, these tools should all be in /usr/bin/. You can run them directly from the command line:

    example$ regina-python
    Regina 4.95
    Software for 3-manifold topology and normal surface theory
    Copyright (c) 1999-2013, The Regina development team
    >>>

If you downloaded a drag-and-drop app bundle for macOS, these tools are all shipped inside it. If you dragged Regina to the main Applications folder, you can find them in /Applications/Regina.app/Contents/MacOS/.

    example$ /Applications/Regina.app/Contents/MacOS/regina-python
    Regina 4.95
    Software for 3-manifold topology and normal surface theory
    Copyright (c) 1999-2013, The Regina development team
    >>>

If you use Windows, the tool regina-python is not available. Windows. However, you can still use Python scripting in Regina's graphical user interface, by opening a graphical Python console or using script packets.

The other command-line tools (such as regfiledump, tricensus and so on) are installed under Windows beneath the Program Files directory; on some machines this directory is called Program Files (x86). Specifically, the command-line tools are stored in the subdirectory c:\Program Files\Regina\Regina 7.3\bin\.

    example$ "c:\Program Files\Regina\Regina 7.3\bin\tricensus.exe" -t2 output.rga
    Starting census generation...
    0:1 0:0 1:0 1:1 | 0:2 0:3 1:3 1:2
    0:1 0:0 1:0 1:1 | 0:2 0:3 bdry bdry
    ...

No! As of version 4.92, Regina ships as a standalone app bundle that you can drag and drop straight into your Applications folder. If you installed Fink for an earlier version of Regina and you do not use it for anything else, you can remove it: simply delete /sw and everything beneath it.

This means that whoever built your version of Regina did not include Python support in the build.

The best solution is to download a ready-made package from the Regina website. All of the ready-made packages should have Python support built in.

If you need to build Regina yourself from source, make sure you have the Python development files installed. If not, Regina will warn you about this when you run cmake:

example:~/source/regina/build> cmake ..
-- The C compiler identification is GNU
-- The CXX compiler identification is GNU
...
... (lots of output)
...
-----------------------------------------------------------------------------
-- The following OPTIONAL packages could NOT be located on your system.
-- Consider installing them to enable more features from this software.
-----------------------------------------------------------------------------
   * Python development  <http://www.python.org/>
     Build Python bindings for Regina

-----------------------------------------------------------------------------

-- Configuring done
-- Generating done
-- Build files have been written to: /Users/bab/source/regina/build
example:~/source/regina/build>

If you are stuck, please mail the authors for assistance, including your CMakeCache.txt if possible to help diagnose the problem.

At the time of writing, SnapPy is not compatible with multiple interpreters. If you run the graphical user interface and import the snappy module in more than one Python console, SnapPy will stop working.

A workaround is to open one console, import snappy within it, and then leave that console open. You can then use SnapPy in as many different consoles as you like: SnapPy will only break after you close that first console.

If you are not working directly with a data file, another option is to use the regina-python command-line tool. This only runs one instance of Python, and so avoids the problem.

The problem appears to be rooted in Cython, which SnapPy uses for its Python bindings. The SnapPy and Regina authors are currently working to find a suitable workaround.

If you can, it is best to install Regina from a ready-made package. See the Regina website for a list of GNU/Linux distributions that have packages available.

If you do need to build Regina yourself, the website offers help on building Regina from source. There is also a page on building Regina on different distributions, which suggests specific cmake options tailored to your particular type of machine.

Sometimes building an application on different hardware or against different versions of libraries can produce unforseen bugs that do not appear on the developer's machine(s). To help guard against such problems, Regina ships with a rich test suite. The test suite asks Regina to perform different calculations that isolate different portions of its mathematical code, and it verifies that Regina gets all the answers correct.

You can only run the test suite if you are building Regina from source yourself. If you download a ready-made package, the person who built the package should have already verified that Regina passes the test suite (as all of the packages on the Regina website do).

You will also need CppUnit installed. Otherwise the test suite will run but only with the simpler Python and command-line utilities tests, not the rich and detailed C++ calculation engine tests.

To run the test suite, move into your main build directory and type make test ARGS=-V. You should see the individual tests being run, as illustrated below.

example:~/source/regina/build> make test ARGS=-V
Running tests...
...
... (some initial output)
...
1: ----------------------------------------------
1: Test suite for Regina's command-line utilities
1: ----------------------------------------------
1:
1: Running censuslookup.test ... ok
1: Running regconcat.test (with filter) ... ok
...
... (more output)
...
2: ---------------------------------------
2: Test suite for Regina's python bindings
2: ---------------------------------------
2:
2: Running alltypes.test ... ok
2: Running angles.test ... ok
...
... (even more output)
...
3: Regina calculation engine test suite
3:
3: AbelianGroupTest::incrementalBuild... ok.
3: AngleStructuresTest::empty... ok.
3: AngleStructuresTest::oneTet... ok.
...
... (lots and lots of output)
...
100% tests passed, 0 tests failed out of 3

Total Test time (real) =  171.41 sec
example:~/source/regina/build>

We see from the output above that Regina passed all of its tests (and hopefully this is what you will see too).

Perhaps something crashed. Maybe the program gave the wrong answer. Or it could be just a little too slow?

Please! - mail the authors and let us know. You are welcome to write to us directly (our email addresses are here). Or even better, use the GitHub issue tracking system so that the problem you report is publicly archived.

This program is permanently in development. There is a very long TODO list, and chances are your problem is on it. And then again chances are it's not. So please, let us know what you think can be fixed or improved.