Subj : Re: sqrt algo
To   : comp.programming
From : Jean-Claude Arbaut
Date : Thu Jul 14 2005 12:42 am




Le 13/07/05 15:10, dans slrndda4mg.2j6n.willem@toad.stack.nl, « Willem »
<willem@stack.nl> a écrit :

> himanshu wrote:
> ) Can anyone shed light on an Algorithm for finding out the square root of
> )   a number? to make it simple lets only consider integers.
> 
> You should ask Isaac, he came up with a pretty nice algorithm for that.

Or babylonians ;-)

u(n+1) = 1/2 * (u(n) + a/u(n))

u(0) > 0

converges to sqrt(a).

And, better, there is a closed form for u(n) (needs to play with cosh).

.