[Haskell-cafe] strictness and the simple continued fraction
William Lee Irwin III
wli at holomorphy.com
Mon Oct 11 23:52:55 EDT 2004
On Mon, Oct 11, 2004 at 09:53:16PM -0400, Scott Turner wrote:
> I tried using continued fractions in a "spiffy lazy list" implementation a
> while ago. Never got them working as well as expected.
> Evenutally I realized that calculating with lazy lists is not as
> smooth as you might expect.
> For example, the square root of 2 has a simple representation
> as a lazy continued fraction, but if you multiply the square root of 2 by
> itself, your result lazy list will never get anywhere. The calculation will
> keep trying to determine whether or not the result is less than 2, this being
> necessary to find the first number in the representation. But every finite
> prefix of the square root of 2 leaves uncertainty both below and above, so
> the determination will never be made.
> Your problems may have some other basis, but I hope this helps.
I hit that one, too. That's nasty enough it may be best to give up on
the infinite case, at least. I can't think of a way to salvage all this.
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