Preparation for a B-Spline grid manager

As I said in the previous post, we decided to skip the inverse mapping temporarily and move towards to the construction of a B-Spline DUNE grid. The final goal is to have all necessary grid components and interfaces to make the VTKwriter work.

For the past two weeks, I spent quite some time to understand the dune gird interface. My original plan was to imitate the OneDGrid. So I read almost all the source code of  the OneDGrid and the common grid interface. Then I found it was a too ambitious plan. DefaultGridView requires a rather complete gird traits which is not easy for me to achieve in a short time. After a late discussion with my mentor, I realized I took a lot of detours and it's important to report my problems and doubts directly when I had them.

Then we tried to build a rather basic B-Spline gird manager. Here I list what I achieved last week:

• A BSplineGrid class
  which wraps the BSplineLeafGridView
• A BSplineLeafGridView class
  which wraps the BSplinePatch and offers access to BSplineGirdLeafIterator
• A BSplineGirdLeafIterator class
  which is a iterator to visit all leaf element(knot spans)

For this week, I'm going to continue with BSplineGridEntity class and more contents of BSplineGirdLeafIterator class.