entropy-postgresql

Aggregate user-defined function to compute Shannon's entropy in PostgreSQL (>=9.4).

The functions are implemented in C and compute the entropy from counts of events. The probabilities are estimated by maximum likelihood from the counts.

Install

1. Compile and install the entropy functions in postgres

make && sudo make install

2. Create the entropy functions in the postgres databases where you want to use them

psql -d <database> -f create_functions.sql

How to use the functions

The file test_functions.sql contains examples using the functions to query a temporary table.