[R] Bessel function

Martin Maechler maechler at stat.math.ethz.ch
Thu Sep 16 10:25:45 CEST 2004


>>>>> "Christian" == Christian Stratova <cstrato at aon.at>
>>>>>     on Wed, 15 Sep 2004 20:15:08 +0200 writes:

    Christian> You can find C++ source code for Bessel function and similar
    Christian> functions for example here:
    Christian> http://root.cern.ch/root/htmldoc/src/TMath.cxx.html

but as Prof Ripley has said much earlier in this thread :

Why don't you use the C version from R's source?  R is Open Source !!

R's version (of the *four* most common Bessel functions) stems
from the  Netlib "Specfun" collection, 
was ported to C by me and has been slightly fixed more than once
AFAIR.


    Christian> Hope this helps

    Christian> Best regards
    Christian> Christian
    Christian> -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
    Christian> C.h.r.i.s.t.i.a.n. .S.t.r.a.t.o.w.a
    Christian> V.i.e.n.n.a.         .A.u.s.t.r.i.a
    Christian> -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-

    Christian> Ravi Varadhan wrote:
    >> Dear Beat,
    >> 
    >> You might also want to look at the book by Zang and Jin -  Computation of Special Functions, John Wiley.  They have Fortran sources for all the special functions covered in there.
    >> 
    >> Ravi.
    >> 
    >> Ravi Varadhan, Ph.D.
    >> Assistant Professor,  The Center on Aging and Health
    >> Division of Geriatric Medicine and Gerontology,
    >> Johns Hopkins University,
    >> 2024 E. Monument Street, Suite 2-700
    >> Baltimore, MD 21205.
    >> (410) 502 - 7806.
    >> 
    >> ________________________________
    >> 
    >> From: r-help-bounces at stat.math.ethz.ch on behalf of beat.huggler at rmf.ch
    >> Sent: Wed 9/15/2004 4:24 AM
    >> To: R-help at stat.math.ethz.ch
    >> Subject: [R] Bessel function
    >> 
    >> 
    >> 
    >> 
    >> 
    >> Dear all
    >> 
    >> Currently, I'm implementing the generalized hyperbolic distribution into
    >> Splus. Unfortunately the Bessel function is not implemented in Splus. In
    >> R the Bessel function does exist but it is an internal function and I'm
    >> not able to look at the code.
    >> 
    >> Is there any possibility to see the code of the Bessel function in R or
    >> does anybody has an implementation of the Bessel function in Splus?
    >> 
    >> Thanks a lot for your help.
    >> 
    >> Beat




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