sympy/sympy — pull request #1428 by gdevanla (2012-07-18 16:24:45+00:00)
Title: Trace and partial trace operations on qubits

This PR has all changes related to "Trace and Reduced trace operations on Qubits". It also extends qapply() to work with density operators. Examples, have been added to examples/notebook, and a screen shot of examples can be found at http://wp.me/p2lo7k-3m

The PR might need a re-base later on, but I am submitting this to start the review process.