R help - Mar 2004 - Question on deriv3()

Hello:

Why is deriv3() functioning differently in R from that in Splus
using library(MASS) ? For example
deriv3(~(t1*log(t2)+lgamma(t1)+(1-t1)*log(y)+y/t2),c("t1","t2"),function(y,t1,t2)NULL)
complains of  lgamma.

Mervyn

Because it is not the same code.  In R, the set of known functions is 
hard-coded.  In S-PLUS, it is extensible, and was extended by MASS (now 
incorporated into the standard distribution).

On Tue, 23 Mar 2004, Mervyn G Marasinghe wrote:
> Why is deriv3() functioning differently in R from that in Splus
> using library(MASS) ? For example
>
deriv3(~(t1*log(t2)+lgamma(t1)+(1-t1)*log(y)+y/t2),c("t1","t2"),function(y,t1,t2)NULL)
> complains of  lgamma.
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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