libnabo is a fast K Nearest Neighbour library for low-dimensional spaces. It provides a clean, legacy-free, scalar-type–agnostic API thanks to C++ templates. Its current CPU implementation is strongly inspired by ANN, but with more compact data types. On the average, libnabo is 5% to 20% faster than ANN.

Homepage:
https://github.com/ethz-asl/libnabo
