Computing the digits of π in PostgreSQL
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
-- ref https://www.cs.ox.ac.uk/people/jeremy.gibbons/publications/spigot.pdf | |
with recursive pigen(q, r, t, i, y, n) as ( | |
select 1::decimal, 180::decimal, 60::decimal, 2, 0::decimal, 0 | |
union all select 10*q*i*(2*i-1), 10*u*(q*(5*i-2)+r-y*t), t*u, i+1, y, n+1 | |
from (select q, r, t, i, n, 3*(3*i+1)*(3*i+2) as u, div(q*(27*i-12)+5*r,(5*t)) as y from pigen) as tmp | |
where n < 1000 | |
) | |
select string_agg(y::text, '') pi | |
from pigen where n > 0; |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment