sympy/sympy — pull request #2105 by mrocklin (2013-05-13 22:14:42+00:00)
Title: MatrixElement._eval_simplify

`MatrixElement._eval_simplify` returns self

Fixes 3814

Alternatives:

https://github.com/sympy/sympy/pull/2093
https://github.com/sympy/sympy/pull/2095