[Numpy-discussion] any interest in including asecond-ordergradient?
Thu Oct 30 10:18:50 CDT 2008
> 2008/10/29 Fernando Perez <firstname.lastname@example.org>:
>> 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.
I'm basically in favour of Fernando's suggestion to keep gradient
simple and add a hessian function. Higher numerical derivatives from
data aren't very reliable anyway. You're much better off interpolating
with a polynomial and then differentiating that.
> 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
Improving the support for a gradient of array data is an entirely
independent project in my mind - but I like this idea and I replied in
a new thread.
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