The version presented below is also known as the Gauss–Euler, Brent–Salamin (or Salamin–Brent) algorithm;Brent, Richard, Old and New Algorithms for pi, Letters to the Editor, Notices of the AMS 60(1), p. 7 it was independently discovered in 1975 by Richard Brent and Eugene Salamin. It was used to compute the first 206,158,430,000 decimal digits of on September 18 to 20, 1999, and the results were checked with Borwein's algorithm.
