Summary:
Pull Request resolved: https://github.com/facebookresearch/faiss/pull/2562
Introduce a table of transposed centroids in ProductQuantizer that significantly speeds up ProductQuantizer::compute_codes() call for certain PQ parameters, so speeds up search queries.
* ::sync_tranposed_centroids() call is used to fill the table
* ::clear_transposed_centroids() call clear the table, so that the original baseline code is used for ::compute_codes()
Reviewed By: mdouze
Differential Revision: D40763338
fbshipit-source-id: 87b40e5dd2f8c3cadeb94c1cd9e8a4a5b6ffa97d
Alexandr Guzhva