Report - pg-randomness released on pgFoundry
Today I released the project pg-randomness on pgFoundry. This project provides C language functions to PostgreSQL that support some statistical calculations to determine the randomness of data (in the bytea format), such as:
Any feedback is welcome!
By the way: There is a quick solution in case you need to concatenate many bytea values using an aggregate function. For example, suppose you would like to calculate the entropy of a all bytea values in your table concatenated. Note that this cannot be done by simply calculating the entropy value-wise and using the average entropy as total entropy. What you'd like to do is something like the following:
SELECT byte_entropy(bytea_concat(my_data)) GROUP BY xyz;
Since there is no bytea_concat aggregate function per se, define it first using the following statement:
bytea x := bytea_concat(bytea) aggregation function
CREATE AGGREGATE bytea_concat (bytea) ( sfunc = byteacat, stype = bytea, initcond = '' );