On 17/02/2017 1:59 PM, Jerry Lewis 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.
The nlsr package allows you to specify derivatives.
Duncan Murdoch
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