Re: [ANN] lua-kdtree

[Geoff Leyland <geoff_leyland@...>]

Sorry, that first url should be: https://github.com/geoffleyland/lua-kdtree

On 24/01/2014, at 2:06 pm, Geoff Leyland <geoff_leyland@fastmail.fm> wrote:

> Hi,
> 
> kdtree [1] is an implementation of a kdtree spatial index [2].  A kdtree is a data structure that allows you to quickly find which objects intersect with a given query box.  I use them to quickly query geospatial data, but I believe they’re also used in 3D scene drawing.
> 
> Particular features of this implementation are that:
> - it has a nice, efficient iterator interface
> - it’s n-dimensional (not just 2 dimensional)
> - objects contained in the tree can be boxes, not just points (I don’t know why, but I’ve seen quite a few implementations that only contain points)
> - it’s read-only (that’s not necessarily a good feature)
> - it can read and write the tree to a text file
> - if you use LuaJIT, it uses C structures and malloced memory to allow you to construct larger trees without running into memory space constraints
> - if you use LuaJIT and have ljsyscall and lua-mmapfile, it can read and write the tree to binary files for very rapid tree loading.
> 
> Cheers,
> Geoff
> 
> 
> [1] https://github.com/geoffleyland/kdtree
> [2] http://en.wikipedia.org/wiki/K-d_tree
> [3] https://github.com/justincormack/ljsyscall
> [4] https://github.com/geoffleyland/lua-mmapfile