README for the link & code implementation

What is this?

Link & code is an indexing method that combines HNSW indexing with compression and exploits the neighborhood structure of the similarity graph to improve the reconstruction. It is described in

@inproceedings{link_and_code,
   author = {Matthijs Douze and Alexandre Sablayrolles and Herv\'e J\'egou},
   title = {Link and code: Fast indexing with graphs and compact regression codes},
   booktitle = {CVPR},
   year = {2018}
}

ArXiV here

The necessary code for this paper was removed from Faiss in version 1.8.0. For a functioning version, use Faiss 1.7.4.