[Doc] Add installation instructions for Ubuntu PPA

Cherry-pick of trunk r3164.

git-svn-id: https://cantera.googlecode.com/svn/cantera/branches/2.1@3165 02a645c2-efd0-11dd-984d-ab748d24aa7e

doc/sphinx/faq.rst

@@ -15,7 +15,12 @@ Installation
 
 **How do I install Cantera on Linux?**
 
-    Download the source code (e.g. ``cantera-2.1.2.tar.gz``) from `SourceForge
+<<<<<<< HEAD
+    For Ubuntu, packages for the current stable version of Cantera are available
+    in a PPA. See :ref:`Ubuntu Installation <sec-install-ubuntu>` for details.
+
+    For other Linux distributions, download the source code (e.g.
+    ``cantera-2.1.2.tar.gz``) from `SourceForge
     <https://sourceforge.net/projects/cantera/files/cantera/>`_ and follow the
     instructions in the :ref:`sec-compiling`.
 

doc/sphinx/install.rst

@@ -193,3 +193,38 @@ Install Cantera by adding the desired options to the ``brew install`` command,
 e.g.::
 
     brew install cantera --devel --with-matlab=/Applications/MATLAB_R2014a.app/
+
+.. _sec-install-ubuntu:
+
+Ubuntu
+======
+
+Ubuntu packages are provided for recent versions of Ubuntu using a Personal
+Package Archive (PPA). As of Cantera 2.1.2, packages are available for Ubuntu
+12.04 LTS (Precise Pangolin) and Ubuntu 14.04 LTS (Trusty Tahr). To see which
+Ubuntu releases and Cantera versions are currently available, visit
+https://launchpad.net/~speth/+archive/ubuntu/cantera
+
+The available packages are:
+
+- ``cantera-python`` - The Cantera Python module for Python 2. For Ubuntu 12.04,
+  this is the "legacy" Python module. For Ubuntu 14.04 and newer, this is the
+  "new" Python module.
+
+- ``cantera-python3`` - The Cantera Python module for Python 3. Only available
+  for Ubuntu 14.04 and newer.
+
+- ``cantera-dev`` - Libraries and header files for compiling your own C++ and
+  Fortran 90 programs that use Cantera.
+
+To add the Cantera PPA::
+
+    sudo aptitude install python-software-properties
+    sudo apt-add-repository ppa:speth/cantera
+    sudo aptitude update
+
+To install all of the Cantera packages::
+
+    sudo aptitude install cantera-python cantera-python3 cantera-dev
+
+or install whichever subset you need by adjusting the above command.