

Efficient represention for growing circles in 2D space? - DanWaterworth
http://stackoverflow.com/questions/9031778/efficient-represention-for-growing-circles-in-2d-space

======
akg
If you have a large domain with a large number of N circles, you could try
using a B-Tree like approach. Basically partitioning your domain in a N-Tree
(instead of a traditional quad-tree). The wide branching factor per node will
give you a shallower tree that's more efficient if you are doing lots of
updates to the data-structure. You can also rid yourself of pointers to do
really fast traversals through your N-Tree using an approach like
([http://www.matmidia.mat.puc-
rio.br/tomlew/publication_page.p...](http://www.matmidia.mat.puc-
rio.br/tomlew/publication_page.php?pubkey=fastdualoctree_sgp)). Lewiner et.
al. talk about oct-trees there, but it could be generalized.

I have some code that implements such a data-structure in 3D (should be easily
modifiable to 2D). I can mail you the source if you are interested.

~~~
ajuc
Well, growing 2d circles are just static sliced cones in 3d.

So maybe some 3d space partitioning technique will do.

EDIT: but I can't really think of any suitable for indexing big long cones. So
it's no really useful idea :/

------
mchouza
You can try posting your question in <http://cstheory.stackexchange.com/>

