KDTree bug

[scottpdo]

KDTrees occasionally enter an infinite loop when rebalancing.

Unfortunately it appears inconsistent, but probably has to do with specific agent positions and the median comparing them to. Can occasionally (rarely) be seen in the Flocking model: https://codesandbox.io/s/flocking-vw76q

[scottpdo]

Whew, fortunately not an issue with KDTrees themselves, rather with the implementation of the Flocking model. When looking at a neighbor occupying the same position, the separation Vector got assigned an infinite value, which ends up resolving to NaN somewhere in the calculations... KDTree can't handle NaN values, so it threw up its hands and kept on trying to rebalance.

tl;dr not a library issue!