Pre-reviewing of merging LinearEquation into MathLib
Sorry this is not a real pull request. I would like to ask people to take a look at current implementation of LinearEquation and think about interface to linear equation data and operations. If it's not nice to using pull request in this way, let me know. I'll remove it and find another way.
What I'd like to point out is
- Eigen is used as default matrix and vector data type because of its expression templates and efficiency
- Lis is used as default linear solver because Lis provides several preconditioners and solvers and it's easy to integrate the codes.
- Unified interface (ILinearEquation class) is introduced for easily integrating external libraries
Once the discussion is settled down, I can make a real pull request.
Best, Nori