This faiss hnsw index was generated on 2021/10/23 using the repo https://github.com/castorini/CQE (see command Inference section) on Orca (Passage encoding on graham).

Both the hyperparameter M and efConstruction are set to 256. 
Note that in the future the index name should be renamed as faiss-hnsw.cast2019.tct_colbert-v2