Re: Fermi-Dirac integral

From: Jacek M. Holeczek <holeczek_at_us.edu.pl>
Date: Fri, 21 Jan 2005 15:46:27 +0100 (MET)


Hi,

> I need to calculate some Fermi-Dirac integrals (0 to infinity) for
> functions in form :
> > x^n
> > f(x,n,u) = ---------------
> > (e^(x - u) + 1)
> where n = 2,3,4 (natural) and u = something between 0.0 and 5.0 (real)

Well, I have found that for this special case "n = 1,2,3,4 (natural)" I can use the CERNLIB function GPLG (MATHLIB C321) to calculate it :

        -1.0 * TMath::Factorial(n) * real(GPLG(n, 1, (-1.0 * TMath::Exp(u)))) So, for the moment I am fine ...

Hoverer, I think I would like to find a more "general" solution ... not restricted to natural "n" ... so, if anybody knows how to do it using CERNLIB functions, please let me know.

Best regards,
Jacek. Received on Fri Jan 21 2005 - 15:46:37 MET

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