Thanks for the feedback. It was basically a disposable example of something to learn the language with. All the examples in all the tutorials are toy problems and all the systems put forward as having been written in haskell are huge. A collection of medium solutions that folks could use to see how someone who knows the language would solve the problem would go a long way to bridge the gap. -ljr Henning Thielemann wrote:
On Fri, 30 Sep 2005, Lanny Ripple wrote:
newton_h, next_x_h, dy_h :: (Fractional a, Ord a) => (a -> a) -> a -> a -> a newton_h f x h = until ((<= h) . abs . f) (next_x_h f h) x
If this shall be more than a disposable example, I suggest to separate the Newton iteration from the abort of the iteration. Newton's method could return a list of the interim results, a sequence in the mathematical sense. newton :: Fractional a => (a -> (a,a)) -> a -> [a] The function would compute both the value and the derivative, e.g. (\x -> (sin x, cos x))
Then you can easily apply various implementations of a numeric limit. limit :: [a] -> a The most simple implementation is certainly: limit = (!!100)
Eventually a function numericDiff :: Fractional a => a -> (a -> a) -> (a -> (a,a)) could extend a function by some difference quotient.
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Lanny Ripple