On Wed, Nov 28, 2012 at 3:52 AM, Phil Endecott < spam_from_boost_dev@chezphil.org> wrote:
Dear All,
A while ago I posted a question about augmented trees:
There has also been other discussion recently in this thread:
Unfortunately I have been manically bug-hunting for the last few weeks [*] and wasn't able to follow-up properly until now. Here are my thoughts:
I'm aware of 3 applications for augmented trees: - O(log N) indexing, insertion and deletion; "best of list and vector" (i.e. Countertree). - Similar where the "value" of each node is variable, so one can accumulate over any range in O(log N) time (i.e. stl_ext_adv). - Interval trees.
This list does not include R-trees suggested by Adam Wulkiewicz. In the general case this is the best choice, since these trees work with both two and one dimensional extension rectangles. Only if you are sure that one dimensional extension intervals are sufficient for the problem you can use one of the listed data structures or containers. However, if some time later the problem becomes two dimensional the solution can not be fixed by adding another container for y-coordinate. This approach is not optimal. For the best performance you will need to re-implement the solution using R-trees.
Here is an interesting augmented tree implementation that attempts to be generic:
This seems to work by exposing the tree structure in the iterator (i.e. the iterator has parent(), left() and right() methods that return other iterators), and by requiring a Customization class that is called to updated augmented data in a node when its children change.
These trees provide facilities and extensions of STL containers similar to Countertree and augmented B+ trees. They do not offer efficient logarithmic time join and split operations. Note also, that the author says that this project is mostly for educational purposes. Regards, Vadim Stadnik