On Fri, 23 Mar 2007, Neil Mitchell wrote:
Hi Longesh
But I've found learning Haskell so tough (this is my 4th try in the last two years) that I feel I have to bore everyone with my first non-trivial program.
Well done on getting something going!
my_sqrt t = last (take 20 (iterate (\n -> n/2 + t/(2 * n)) t))
http://darcs.haskell.org/htam/src/Numerics/ZeroFinder/Newton.hs with inverse t (\x->(x^2,2*x)) t
It is a bit crude though. 20 iterations is a bit arbitrary. I don't suppose there is a easy way to iterate until the results stop changing.
close (x:y:xs) | abs (x - y) < 0.1 = y close (x:xs) = close xs
I don't know how to add it into the one liner though - although I suspect someone here will :)
http://darcs.haskell.org/htam/src/Numerics/Sequence.hs limitDifference :: (Real a) => a -> [a] -> a limitDifference tol xs = case dropWhile ((> tol) . abs . uncurry (-)) $ zip xs (tail xs) of ((_,x):_) -> x [] -> error "limitDifference: Finite sequence, but no element satisfies abort criterion."