pgxicor is a Postgres extension that exposes a SELECT xicor(X, Y) aggregate function. XI can detect functional relationships between X and Y. You can use it as

pgxicor is a Postgres extension that exposes a SELECT xicor(X, Y) aggregate function. XI can detect functional relationships between X and Y. You can use it as a more powerful alternative to standard corr(X, Y) which works best on linear relationships only.