Julian Kent's kd-tree

is Julian Kent's kd tree faster than Rednaxela's or is it the other way around

They're pretty much tied. Mine might be a little faster on systems where the data in the Kd-Tree is frequently pushed out of cache.

is third generation Rednaxela faster than Julian Kent

No, as I said above, they are mostly the same except for cache conditions.

what about second generation Rednaxela and first generation Rednaxela

3rd gen is the fastest of Rednaxela's trees. There's also a k-NN algorithm benchmark if you want to run some tests.

Voidious can you make a version of knn.jar with Julian Kent's tree and give instructions on how to use knn.jar on ubuntu 13.04

I've never used it, sorry.

Why not just pick Skilgannon's or Rednaxela's and go with it? The speed difference will be negligible. Unless you're locked into some insane batch job on a supercomputer upon choosing, I reckon you'll spend more time trying to evaluate them than you'll save by using one over the other.

what's the difference between drussgt 3.0.0's kd-tree and drussgt 3.0.1's kd-tree

Try using this knn.jar, it has both trees as an option. Although that one isn't using my latest tree, you should be able to figure out how to change which tree it is using.

Seriously, the different in performance between RedGen3 and Skil are pretty negligible. You'd be better off putting the time into figuring out how to reduce a dimension of the data you're storing, or something like that, which will actually provide a speedup.

how do i change which tree its using