No, computer algebra systems such as yacas do symbolic differentiation. Automatic differentiation is a numerical technique that can be used to find derivatives of functions that can be implemented as computer programs, through successive uses of the chain rule on the computer code itself. It would be cool if R could either do AD or interface to an AD package. R can be used with ADmodelbuilder (see http://otter-rsch.ca/admbre/examples/glmmadmb/glmmADMB.html) , a proprietry program, but an open source solution would be nice.
Cheers, Simon. On Thu, 2008-05-08 at 03:09 +0000, David Winsemius wrote: > "Erin Hodgess" <[EMAIL PROTECTED]> wrote in > news:[EMAIL PROTECTED]: > > > Is there a package for automatic differentiation, please? > > > > Have you looked at Goedman, Grothendieck, Hojsgaard, and Pinkus' Ryacas? > > >From the Ryacas documentation: > Analytical derivatives of functions can be evaluated with the D() and > deriv() functions: > > > yacas("D(x) Sin(x)") > > expression(cos(x)) > -- Simon Blomberg, BSc (Hons), PhD, MAppStat. Lecturer and Consultant Statistician Faculty of Biological and Chemical Sciences The University of Queensland St. Lucia Queensland 4072 Australia Room 320 Goddard Building (8) T: +61 7 3365 2506 http://www.uq.edu.au/~uqsblomb email: S.Blomberg1_at_uq.edu.au Policies: 1. I will NOT analyse your data for you. 2. Your deadline is your problem. The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data. - John Tukey. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
