[Numpy-discussion] any interest in including asecond-ordergradient?

Stéfan van der Walt stefan@sun.ac...
Thu Oct 30 01:33:23 CDT 2008


Hi Fernando,

Thanks for your input.

2008/10/29 Fernando Perez <fperez.net@gmail.com>:
> I think it's fine to ask for functions that compute higher order
> derivatives of n-d arrays: we already have diff(), which operates on a
> single direction, and a hessian could make sense (with the caveats
> David points out).   But with higher order derivatives there are many
> more combinations to worry about, and I really think it's a bad idea
> to lump those issues into the definition of gradient, which was a
> perfectly unambiguous object up until this point.

Maybe we should focus on writing a decent 'deriv' function then.  I
know Konrad Hinsen's Scientific had a derivatives package
(Scientific.Functions.Derivatives) that implemented automatic
differentiation:

http://en.wikipedia.org/wiki/Automatic_differentiation

Cheers
Stéfan


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