Test empty NeighborSearch objects and Train().
Test empty NeighborSearch objects and Train().

stereomatchingkiss/mlpack,theranger/mlpack,lezorich/mlpack,ajjl/mlpack,darcyliu/mlpack,ranjan1990/mlpack,theranger/mlpack,ajjl/mlpack,theranger/mlpack,ajjl/mlpack,ranjan1990/mlpack,palashahuja/mlpack,stereomatchingkiss/mlpack,ranjan1990/mlpack,palashahuja/mlpack,darcyliu/mlpack,darcyliu/mlpack,lezorich/mlpack,palashahuja/mlpack,stereomatchingkiss/mlpack,lezorich/mlpack