how to implement a function in kd-tree ?

hei,

i need to compare 100000 points (xy) whether they are within a certain distance (radius) of each other.

i am using the function isPointInCircle.m http://www.mathworks.com/matlabcentral/fileexchange/7844-geom2d/content/geom2d/geom2d/isPointInCircle.m

and have compiled the kd-tree:

https://sites.google.com/site/andreatagliasacchi/software/matlabkd-treelibrary

my problem is now, how to implement now the function in the kd-tree function.

i never worked with this kd-tree before.