From murdoch.duncan at gmail.com  Sat Feb 18 00:04:38 2017
From: murdoch.duncan at gmail.com (Duncan Murdoch)
Date: Fri, 17 Feb 2017 18:04:38 -0500
Subject: [Rd] Wish List: Extensions to the derivatives table
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Message-ID: <4d84ab5a-7b52-6989-a001-ad147dedfb0b@gmail.com>

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



[Rd] Wish List: Extensions to the derivatives table
Duncan Murdoch