sympy/sympy — pull request #2190 by SaurabhJha (2013-06-19 07:54:47+00:00)
Title: SparseMatrix Arithmetic

This is a tentative add and sub functions for sparse matrix. It is here so as to get reviews about the general approach to the problem. I realised lately that line 50 and line 81 can be made more efficient by sorting ja and then applying binary search on them. Also the code can be more concise although I coulden't see any way to do it.