You aren't supposed to index vectors larger than ~128 dimensions. Because of concentration of measure which is an aspect of the curse of dimensionality the dist

You aren't supposed to index vectors larger than ~128 dimensions. Because of concentration of measure which is an aspect of the curse of dimensionality the distances between high-dimensional vectors tend to become identical. You need to do dimensionality reduction before indexing. Basically it's fine to just pick n first components if you don't want anything fancy.