To Do List

• GUI

  • Display volumes of cusp neighborhoods in the cusp viewer. (Requested by Saul.)
  • Allow negative horoball displacements. (Requested by Saul.)
  • Allow you to get the info (position, radius) of a horoball by clicking it.

• Documentation

  • More hyperlinks
  • Expand tutorial
  • Make more screencasts

• snappy

  • Wrap splittings functions (also requested by Saul).
  • Longitude detection in manifolds with a single torus cusp (ie, the slope that dies in homology). Requested by Saul.
  • Add a KnotTheory style PD constructor: Manifold(“PD[ X[1,9,2,8], X[3,10,4,11], X[5,3,6,2], X[7,1,8,12], X[9,4,10,5], X[11,7,12,6] ]”) (requested by Slavik J.)
  • Use the previous item to strip out the crusty C++ code from addl_code.

• Kernel

  • Merge Jeff’s changes into SnapPy’s copy of the kernel.
  • After this, consider making SnapPy’s copy the canonical one by definition.
  • Improve the situation with uFatalErrors.

• Minor

  • dual_curves should really cache it’s result and have this used by drill
  • One should be able to convert a SymmetryGroup to a Sage permutation group.
  • Also, the SymmetryGroup presentation function should be wrapped. There is code for this in the old SnapPeaPython.

• Ambitious

  • A new basic (sub)class: S3Knot (and/or S3Link).

  • Consider adding a HeegaardSplitting class

  • Consider merging our t3m project and normal surface code into SnapPy.

  • Redo much of Snap in the context of Sage/SnapPy.

    • Add a method for computing tetrahedron shapes to arbitrary precision.
    • Add methods for computating invariant trace fields and related number fields.
    • Add a method which implements and extends Harriet Moser’s algorithm to allow SnapPy to prove that a manifold is hyperbolic.

Development Basics

Submitting patches

We’re using mercurial, and you can get a copy of the repository via:

hg clone static-http://www.math.uic.edu/t3m/hg/SnapPy

After editing the files, commit your changes to the local repository via:

hg commit -m "Fixed cache issue with sending from plink"

Then do:

hg log -l 5

changeset: 396:a5a0809a371d
tag: tip
user: Nathan Dunfield <nathan@dunfield.info>
date: Fri Oct 02     09:07:33 2009 -0500
summary: Fixed cache issue with sending from plink
...

to get the changeset number(s) of your commits and then do:

hg export -g 396:a5a0809a371d > plink_cache.patch

and mail us the file “plink_cache.patch”.

OS X

Here is how to get a clean development setup under OS X, versions 10.5-10.7.

• Install Active Tcl/Tk 8.5.12 (not 8.4 or 8.6) from ActiveState.

• Install Python 2.7 using the Mac Installer Disk Image. There are currently two versions, one for 10.3 and up (ppc/i386) and one for 10.6 and up (i386/x86_64). Either should work ok. Actually, releases are built with a custom Python for 10.5+ for i386/x86_64. Set your path so that “python” is:

  /Library/Frameworks/Python.framework/Versions/2.7/bin/python

• Then install distrubute, a Python package manager:

  curl -O http://python-distribute.org/distribute_setup.py
  python distribute_setup.py

  and use it to install the following packages:

  python -m easy_install mercurial   # Source code control software
  python -m easy_install Cython      # Used for Python-C interfacing
  python -m easy_install Sphinx      # For building the documentation
  python -m easy_install ipython     # Improved Python shell
  python -m easy_install py2app      # For making app bundles

• Get the source code from the repository, using the version of “hg” that is in the same directory as Python 2.7:

  hg clone static-http://www.math.uic.edu/t3m/hg/plink
  hg clone static-http://www.math.uic.edu/t3m/hg/SnapPy

• This may not be necessary, but to make sure Python will use Tk 8.5.11 instead of (for instance) the system version of Tk, in “SnapPy/release_tools/tkinter-versions” run the script ”./install_tkinter 8.5”. (If you don’t have both Python 3.2 and 2.7 installed on your system, it will complain. But you can ignore this.)

• Test the stand-alone link editor:

  cd plink
  python setup.py install
  python -m plink.app   # Link editor appears!

  This last command runs the script “plink/app.py”; the real code for the link editor is in “plink/__init__.py”.

  To make sure it’s using the right Tk, select “File->About Python...” and make sure the version is 8.5.11, not 8.4.* or 8.5.7.

  Building the proper Mac application bundle (not necessary for testing, typically):

  cd plink-app
  python setup.py py2app
  open dist    # This directory contains the clickable app.

• Now build SnapPy itself. One builds it twice to generate the documentation, much of which is extracted from the installed module:

  cd ../../SnapPy/pari
  sh build_pari.sh     # Used to compute homology
  cd ..
  python setup.py install
  python setup.py build_docs install

  If ”.” is in your path, you’ll need to change directory before starting SnapPy; otherwise it will attempt to load ”./snappy” which lacks the binary module:

  cd SnapPyApp
  python -m snappy.app   #SnapPy starts!

  To build the clickable app, just do the following in the SnapPyApp directory:

  python setup.py py2app

Some major parts of the SnapPy codebase are:

• “SnapPy.pyx”: The Cython interface to the SnapPea kernel
• “opengl/CyOpenGL*.pyx”: The Cython interface to OpenGL*
• “snappy/app.py”: The core GUI code
• “snappy/polyviewer.py”: The GUI code for Dirichlet domains
• “snappy/horoviewer.py”: The GUI code for horoball pictures
• “snappy/database.py”: Interacts with the sqlite3 manifold database

In addition, Jeff’s old prototype for a Tk-based UI can be found in “misc/JeffsOldUI/SnapPeaGUI.py”; just run Python on this file to try it out, after installing PythonMegaWidgets.

Windows XP

Install Python 2.7, MinGW (including g++, MSYS-base, and the MinGW Development Tookit), Inno Setup, Mercurial, and PyReadine via their binary installers. Due to this bug, you need to edit by hand the file:

c:Python27/Lib/distutils/cygwinccompiler.py

Inside the Mingw32CCompiler class there’s a call to “self.set_executables” and there you should remove all of the “-mno-cygwin” options.

Then install setuptools just by downloading ez_setup.py and double-clicking it. Then download the latest version of Cython into the directory “c:Python27”. In MSYS do the following:

cd c:Python27
tar xfz Cython-*.tar.gz
cd Cython-*
../python.exe setup.py build -c mingw32
../python.exe setup.py install
cd ../
python.exe -m easy_install sphinx
hg clone static-http://www.math.uic.edu/t3m/hg/SnapPy
cd SnapPy
sh build_pari.sh
../python.exe setup.py build -c mingw32
../python.exe setup.py install
../python.exe setup.py build_docs
../python.exe setup.py install
cd ../
python.exe -m snappy.app

If that works, install py2exe via the binary installer. Then:

cd SnapPy/SnapPyExe
export PATH=$PATH:/c/Python27:/c/Program\ Files/Inno\ Setup\ 5/

Now replace line 13 of make.py with the commented-out line 12. Then:

python make.py