ggrothendieck at gmail.com
Thu Jan 31 20:09:04 CET 2008
You can only use those functions that Ryacas knows about
or that Yacas 1.0.63 knows about:
The Ryacas home page http://ryacas.googlecode.com
has links to the yacas home page.
Sometimes using the first few terms of the Taylor representation is
On Jan 31, 2008 12:01 PM, Doran, Harold <HDoran at air.org> wrote:
> I'm tinkering around in Ryacas trying to find an easy way to get the
> first and second partial derivatives of mu and sigma from a normal
> distribution (actually a bitterly ugly likelihood but this example works
> for now).
> I've done all of the work in Mathematica, but I then need to manually
> write R code whereas I think Ryacas will give me the expression such
> that I can export for Tex and produce code I can use for a function. Is
> there a way I can use Ryacas with built in functions, like dnorm?
> For example, I can define the normal and then use the D function as:
> ndist<-expression( (1/(s*sqrt(2*pi))) * exp(- ((x-u)^2/(2*s^2))))
> D(ndist, "u")
> But, I don't see in the vignette a way to use dnorm?
> R-help at r-project.org mailing list
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
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