Implementation of tree types - Week 6

Last week I had been working on some fixes of the RectangleTree class, including the removal of RectangleTree::Points(), the removal of RectangleTree::Children() and the optimization of RectangleTree::NumDescendants().

The removal of the Children() method requires to make SplitType, AuxiliaryInformationType and DescentType friends of the RectangleTree class. The optimization of NumDescendants() method allows Descendant() to take $O( N)$ operations instead of $O(N)$.

Moreover, I finished the R+/R++ tree implementation. Namely, I replaced SortStruct by std::pair in MinimalCoverageSweep and MinimalSplitsNumberSweep, I simplified the code of MinimalCoverageSweep and I fixed the error with addition of a huge amount of equal points.

Unfortunately, I failed in the implementation of the PiecewiseBallBund class since I am not able to think out any cost-efficient method of finding the distance between a point and a piece-wise ball bound. The problem is not easy even in 2 dimensions.