From t.yee at auckland.ac.nz  Sun Oct 14 23:23:42 2007
From: t.yee at auckland.ac.nz (Thomas Yee)
Date: Mon, 15 Oct 2007 10:23:42 +1300
Subject: [Rd] Extending deriv3()
Message-ID: <471288DE.2090500@auckland.ac.nz>

Hello,

I was wondering if the functions deriv3(), deriv() etc. could be extended
to handle psigamma() and its special cases (digamma(), trigamma()
etc.). From the error message it seems that 'psigamma' needs to be
added to the derivatives table.
This might be easy since psigamma() has a deriv argument.

Additionally, this error message is also obtained when requesting for
the Hessian of the gamma and lgamma functions:

d3 = deriv(~  gamma(y), namev="y", hessian= TRUE)
d3 = deriv(~ lgamma(y), namev="y", hessian= TRUE)

Another class of special functions worth adding are the Bessel functions.

Thanks

Thomas



[Rd] Extending deriv3()
Thomas Yee