DicksonK

I was using all the default parameter which is euclidean. Here is the verbose output before it crash: ``` UMAP(a=None, angular_rp_forest=False, b=None, force_approximation_algorithm=False, init='spectral', learning_rate=1.0, local_connectivity=1.0, low_memory=False, metric='euclidean', metric_kwds=None, min_dist=0.1,...

It works after pynndescent was installed (tested on 2.5m x 75). Also much better performance as well. 0.3.10 (w/o pynndescent) ``` CPU times: user 2h 24min 10s, sys: 49.7 s,...