R help - Oct 2006 - psigamma derivative

Hello,

I am trying to find a hessian matrix  that
involves log(gamma(1/p)) second derivative, p being one of the parameters
of the function. I am using a function "deriv" with the hessian=TRUE
option, but psigamma is not on the list of derivative functions.
I know that it is possible to use 'psigamma(p,deriv)', but it
doesn't work
with 1/p. Does anybody can help with this?

Thanks,
Ana Maria

Try

?Special

For information on the special functions included in the base R
distribution.

Also, 

RSiteSearch("digamma")

gives several hits on additional packages that might be useful.

-Christos

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of anamaria at ufc.br
Sent: Monday, October 30, 2006 3:26 PM
To: r-help at stat.math.ethz.ch
Subject: [R] psigamma derivative

Hello,

I am trying to find a hessian matrix  that involves log(gamma(1/p)) second
derivative, p being one of the parameters of the function. I am using a
function "deriv" with the hessian=TRUE option, but psigamma is not on
the
list of derivative functions.
I know that it is possible to use 'psigamma(p,deriv)', but it
doesn't work
with 1/p. Does anybody can help with this?

Thanks,
Ana Maria

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