[Rd] Wish List: Extensions to the derivatives table

[Avraham Adler]

Hi.

Unless I'm misremembering, log, exp, sin, cos, and tan are all handled in
deriv3. The functions listed are  specially coded slightly more accurate
versions but can be substituted with native ones for which deriv/deriv3
will work automatically. I believe that if you  write your functions using
log(a + 1) instead of log1p(a) or log(x) / log(2) instead of log2(x) deriv3
will work fine.

Thanks,

Avi

On Fri, Feb 17, 2017 at 2:02 PM Jerry Lewis <jerry.lewis at biogen.com> wrote:

> The derivative table resides in the function D.  In S+ that table is
> extensible because it is written in the S language.  R is faster but less
> flexible, since that table is programmed in C.  It would be useful if R
> provided a mechanism for extending the derivative table, or barring that,
> provided a broader table.  Currently unsupported mathematical functions of
> one argument include expm1, log1p, log2, log10, cospi, sinpi, and tanpi.
>
> While manual differentiation of these proposed additions is
> straight-forward, their absence complicates what otherwise could be much
> simpler, such as using deriv() or deriv3() to generate functions, for
> example to use as an nls model.
>
> Thanks,
>
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