Re: PolyGamma function of order n

Hello Andrey,

  for the polygamma function, I reccomend you to use GSL , see

http://www.gnu.org/software/gsl/manual/html_node/Polygamma-Function.html

For using GSL routines in ROOT, see for example:

  http://root.cern.ch/phpBB2/viewtopic.php?t=4730&highlight=gsl

Eventually, if more users are interested, we could include the PolyGamma in in the special functions of MathMore,

  Best Regards

  Lorenzo

On Apr 11, 2007, at 3:03 PM, andreyk1_at_post.tau.ac.il wrote:

> Dear Rooters,
>
> I need to perform some numerical calculations including PolyGamma
> function of
> order n. It is defined as the (n+1)st derivative of the logarithm
> of the gamma
> function: d^n LnGamma(z)/dz^n
>
> (more about the function is here:
> http://mathworld.wolfram.com/PolygammaFunction.html)
>
> I didn't find the appropriate function in TMath, except
> TMath::LnGamma(z), but
> the problem is how can I differentiate n times?
>
> I'd be very grateful for any help.
>
> -------
> OS Windows XP, Root 5.14.00
> --
> Sincerely,
>
> Andrey K.
>
> *************************************************************
> * Andrey Kormilitsin * *
> * * *
> * Department of * *
> * Particle Physics * *
> * School of Physics * Tel: ++ 972- 3 - 640 7954 (o) *
> * Tel Aviv University * *
> * Ramat Aviv,Tel Aviv * E-mail: andreyk1_at_post.tau.ac.il *
> * 69978, ISRAEL * *
> * * *
> *************************************************************
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Received on Fri Apr 13 2007 - 11:32:50 CEST