[pkeenan11]

Holy synchronicity Batman! I just implemented a minhash system that some may find interesting.

The problem is to find (pseudo) inverses of many different proper submatrices of a big square matrix.

Certain matrix identities (Woodbury, banachiewicz) allow you to update the inverse of a “close” submatrix to cheaply calculate a new one.

So you store the inverses you’ve calculated already, with their row/column indices as keys. Then for each new submatrix you want to find a close already-computed inverse to update from.

This is solved with minhashing. You minwise hash the indices so that close matrices are likely to have the same hash.

In my particular implementation I did a “multi-resolution” hash so that I can change the selectiveness of the search as the number of prior computed inverses grows