On Thu, Aug 12, 2004 at 06:59:26PM +0200, Christian Sievers wrote:
blaetterrascheln@web.de wrote:
-- Here's the discrete version of Newton's method for finding -- the square root. Does it always work? Any literature?
I recently used, without range check,
sqrtInt n = help n where help x = let y = ((x + (n `div` x)) `div` 2) in if y
following p. 38f of Henri Cohen, A Course in Computational Algebraic Number Theory, where a proof and a suggestion for improvement (choose a better start value) is given. Your version should be correct as well.
As far as I know, ghc uses gmp, so I wonder if there is access to functions like mpz_sqrt or mpz_perfect_square_p. there isn't.
And on glasgow-haskell-users there is a thread about (a.o.) that subject right now :) Greetings, Remi -- Nobody can be exactly like me. Even I have trouble doing it.