[bug fix] sparse matrix addition and subtraction
SparseMatrix :: Identity Matrix
[critical-bug found] bug with SuperLU? !!
Solving linear system using lsover
code clean up
code clean up
code clean up
bug fix in levenburgMaquart.cpp
[SparseMatrix] getMatrixDataRow bug fix
there is scale issue for derivatives

the derivative computed analytically and numerically are different by a
random scale
validating derivatives numerically
datacost is working fine and fast
constuctor SparseMatrixCV( Mat_<double> ) tested
[temp] commit for Liqun
Push back to my computer
[Important] New SparseMatrix Done
Merge branch 'super_matrix' into develop