# Installing SnapPy

Here are detailed instructions on how to get SnapPy working on a variety of platforms. The current version is 2.3.2 which was released on June 18, 2015.

## Mac OS X

Simply download SnapPy.dmg and copy SnapPy.app to the Applications folder. Double-click to start it, just like any other application. Works with 10.5 and newer on Macs with Intel processors. Users of 10.4 or PPC processors should install SnapPy-1.4.dmg instead.

## Windows

Simply download and run InstallSnapPy.exe.

NOTE: The Windows version of SnapPy depends on the Microsoft Distributable Visual C++ Runtime. If you receive an error message saying “This application has failed to start because MSVCR90.DLL was not found” or “This application failed to start because the application configuration is incorrect” try downloading and installing vcredist_x86.exe from Microsoft.

## Linux

Here are short recipes which work on many Linux systems, with both 32-bit and 64-bit kernels supported. These instructions assume you have system administrator (superuser) privileges; if not, you can install SnapPy into a virtual environment assuming the needed packages are installed. For other systems, try the one closest to yours below, and if that fails, follow the instructions for generic Unix in the next section.

- Fedora/RHEL/CentOS/SciLinux:

      sudo yum install tkinter python-setuptools-devel
      sudo python -m easy_install -U snappy

  Note: For this to work, you may need to set the SELinux Enforcement mode to Permissive or lower.

- Ubuntu/Debian/Mint:

      sudo apt-get install python-tk python-setuptools
      sudo python -m easy_install -U snappy

- PCLinuxOS: Not actually tested, but should work:

      sudo apt-get install tkinter python-setuptools
      sudo python -m easy_install -U snappy

Once you have it installed, do:

    python -m snappy.app

You may get a message about creating a ”.ipython” directory; this is normal, just hit return to continue. There should also now be a command “SnapPy” which does the same thing.

Note: You need to have Python 2.6 or 2.7 to install SnapPy.

## Generic Unix

If you use a Unix other that OS X or Linux, or if the prebuilt packages don’t work for you, you’ll need to build SnapPy from source. Here are some detailed instructions.

Things you’ll need:

- Python with Tkinter: You’ll need to have Python (version 2.6-2.7) and Tk (at least version 8.4) with Tkinter to connect them, including the header files. For instance, on Debian or Ubuntu, install the packages “python-tk” and “python-dev”. On Fedora, you’ll want “tkinter” and “python-devel”. In addition, you’ll need

  - Setuptools, which is typically packaged as “python-setuptools” (Ubuntu/Debian), “python-setuptools-devel” (Fedora).

- Test that Python is in order by installing PLink from source:

      python -m easy_install plink
      plink   # Should start the link editor!

- Support for OpenGL (3D graphics): This is built in on OS X and the most installations of Fedora and Ubuntu. But you’ll need the MESA header files “gl.h” and “glu.h” to compile SnapPy. On Debian and Ubuntu, install “libglu1-mesa-dev”; On Fedora install “mesa-libGLU-devel”.

- Cython, which you can install via:

      sudo python -m easy_install cython

- Sphinx, which you can install via:

      sudo python -m easy_install sphinx

- The gcc C++ compiler, g++, which is not installed by default on some systems, e.g. Ubuntu 11.10.

- CyPari: a stand-alone version of Sage’s Python interface to the PARI number theory library.

Now download the source code listed below, for instance

    curl -L -O snappy-2.3.2.tar.gz
    tar xfz snappy-2.3.2.tar.gz; cd SnapPy

There is one more dependency that need to be dealt with:

- Togl: a 3d widget for Tk. For OS X and Linux, there are pre-built binaries of this in the snappy subdirectory, e.g. snappy/linux2-tk8.4. For Linux these are built for both 32-bit and 64-bit kernels, and should work on most systems. If they don’t, you’ll need to edit or follow “build_togl.sh” to build Togl directly into “snappy/linux2-tk*” (32-bit kernel) or “snappy/linux2-x86_64-tk*” (64-bit kernel), where “*” is the version of Tk you are using.

Finally, compile and install the SnapPy module (which will install certain other dependencies) and test:

    sudo python setup.py install
    sudo python setup.py build_docs install
    cd /tmp; python -m snappy.app

You may get a message about creating a ”.ipython” directory; this is normal, just hit return to continue. There should also now be a command “SnapPy” which does the same thing as “python -m snappy.app”.

## Python Modules for Macintosh or Windows

If you write Python programs on a Macintosh or Windows system, you may wish to install SnapPy as a Python module into your own copy of Python 2.7. After installing Python and setuptools, you may install a SnapPy module from your Terminal application or Command Prompt with the command:

    python -m easy_install -U snappy

OS X notes: For best results, use a Python downloaded from Python.org and not the one provided by Apple. You need at least 10.6 and an Intel processor to use the latest versions of these precompiled modules.

## Virtual Environment

All of the above instructions assume that you want to install SnapPy globally, in the main Python site-packages directory. You can also create a Python virtual environment and install SnapPy into it. For example, to install SnapPy into “mypy/bin” do:

    # Create a virtual environment in new directory "mypy"
    python -m virtualenv mypy
    # Install and run SnapPy!
    mypy/bin/easy_install snappy
    mypy/bin/SnapPy

## Sage

SnapPy has some special features when used within Sage, the universal mathematics software based on Python. You can install it as a Sage optional package via the following if using Sage 6.4 or newer:

    sage -pip install --no-use-wheel snappy

or the following with an older version of Sage:

    sage -python -m easy_install snappy

and as of December 2013 the version of Sage on the SageMathCloud has SnapPy preinstalled!

If you previously installed SnapPy into Sage and want to upgrade SnapPy to the latest version, do:

    sage -pip install --no-use-wheel --upgrade --no-deps  plink spherogram FXrays decorator snappy

or:

    sage -python -m easy_install -U snappy

as appropriate.

If it has trouble when compiling CyOpenGL, you are probably missing the “gl.h” and “glu.h” headers. The graphical features may or may not work, depending on how Tkinter was configured within Sage. If you are using Sage 5.11 or newer, the graphics features may seem to “hang” when you try to start them. If this happens, type “%gui none” at the Sage prompt; please note that doing so will break Sage’s “attach” feature.

## Source code

The complete source code for all platforms: snappy-2.3.2.tar.gz

You can browse our source code repository or clone it using Mercurial via:

    hg clone https://bitbucket.org/t3m/snappy