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From "Phil Steitz" <>
Subject Re: [all][nabla] proposition for a new project in sandbox
Date Tue, 15 Apr 2008 02:18:34 GMT
On Mon, Apr 14, 2008 at 3:35 PM, Jukka Zitting <> wrote:
> Hi,
>  On Mon, Apr 14, 2008 at 9:27 PM, Luc Maisonobe <> wrote:
>  > Derivatives are computed by applying the classical exact differentiation
>  > rules ((f*g)' = f'*g + f*g' and friends) and by using the exact derivatives
>  > of all Math and StrictMath methods (including acosh, asinh and atanh which
>  > are still not available in current versions of Java). The results are as
>  > accurate as machine precision and errors propagation allow. That is to say
>  > the derivative is computed with an accuracy that is tightly related to the
>  > accuracy of the original function.

Interesting from a numerics standpoint, though I guess straightforward
when you think about it. More interesting when you consider that the
original may itself be an approximation.

>  OK, thanks for the details. I'm still not sure about the impact on
>  error propagation, which often works in surprising ways especially for
>  complex functions, but it sounds like you're already getting some good
>  results. Also, have you thought about how to handle branch and loop
>  structures within a function?
>  > This part does work and the existing results show it. You will see them as
>  > soon as I can upload the project somewhere.
>  Sounds great! I'm looking forward to checking it out.

Me too, *nudge, nudge* :)


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