# Talk:Gauss–Legendre algorithm

WikiProject Mathematics (Rated Start-class, Low-importance)
This article is within the scope of WikiProject Mathematics, a collaborative effort to improve the coverage of Mathematics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
Mathematics rating:
 Start Class
 Low Importance
Field:  Analysis

## In base-2?

I can't understand how that doubling of correct digits works in base-2 (or how this algorithm works). Does the number of them grow faster, or is the "initial value" larger? --82.141.93.182 15:31, 3 November 2007 (UTC)

This was just one of those questions made too soon. No need to answer. --82.141.93.182 09:52, 4 November 2007 (UTC)

Why is there Pn? Pn=2^n... —Preceding unsigned comment added by 195.6.234.195 (talk) 13:23, 28 February 2008 (UTC)

## The algorithme only uses O(1) memory

The algorithme itself only uses O(1) memory (i.e. constant), but the description says that it is memory hungry. While it is true that you need a very large memory to store the digits, that has nothing to do with the memory requirements of the algoritm itself. —Preceding unsigned comment added by 130.226.87.164 (talk) 14:09, 25 November 2008 (UTC)

## Error in algoritme?

Using the algoritm I did not get a correct pi; Comparing it with the algoritm in Strang's book about calculus ( which is incomplete) i think that the following changes are neccessary:

t_{n+1}= t_{n} + p * ( a_{n}^2 - a_{n+1}^2)

π ≈ (a_{n}^2 +b_{n}^2)/ (1 - t_{n+1})

Herman Koolstra (talk) 07:37, 24 July 2012 (UTC)