test eigen with mkl
download, extract and rename the dir as 'data' to project root dir: https://drive.google.com/file/d/1EAHFg86aTKnAgHZbpCe7vEgccskYr9Do/view?usp=sharing
Test on i9-13900K @3.0GHz, 24 cores. This is a 100w x 100w sparse matrix, lhs and rhs have 100w dimensions.