Re: [Help-gsl] ln of gamma function for negative arguments

[Brian Gough]

At Wed, 09 Aug 2006 22:00:49 -0400,
Marc Normandin wrote:
> I require the computation of ln of the gamma function for all
> negative non-integer values. The reflection formula can be used for
> half of the negative non-integers along with the log since for half
> the values will be positive. However, I would like to obtain a value
> for the other half. I'm using the ln of gamma as an intermediate
> step after which I raise the result with an exponential, so that
> ultimately I am not after the actual value of ln gamma itself. I am
> open to any methods that work.

GSL has the functions gsl_sf_gamma, gsl_sf_lngamma and
gsl_sf_lngamma_sgn_e which work for both positive and negative x -- I
think those should cover all possibilities.  See the GSL reference
manual for details of the functions.

-- 
best regards, 

Brian Gough

Network Theory Ltd,
Publishing the GSL Manual - http://www.network-theory.co.uk/gsl/manual/