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From: Ken Thomas <kst@ecs.soton.ac.uk>
Newsgroups: comp.lang.ada
Subject: Re: Where I find Bessel function for Ada ?
Date: Wed, 26 Nov 2008 07:09:20 -0800 (PST)
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On Nov 26, 1:08=A0pm, Paul Cole Gloster <Colin_Paul_Glos...@ACM.org>
wrote:
> Reinert submitted:
>
> |----------------------------------------------------------------|
> |"I want to use the modified Bessel function of order 0 in my Ada|
>
> |program. =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=
 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0|
>
> | =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=
 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0|
>
> |Where I find it ?" =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0|
> |----------------------------------------------------------------|
>
> It may be best to write your own version so that you could justifiably
> have an accurate level of confidence of it.
>
> Gautier responded:
>
> !---------------------------------------------------------------!
> !"It is in the Numerical Recipes in Pascal, chapter 6.4, pp 191.!
>
> !All you need to pick the right Pascal source, like bessj0.pas =A0!
>
> !and put it through th P2Ada translator:http://p2ada.sf.net/=A0 !
>
> !The NR sources are freely available on the Internet." =A0 =A0 =A0 =A0 =
=A0!
> !---------------------------------------------------------------!
>
> I have not thoroughly assessed that particular part of "Numerical
>
> Recipes", but some parts of "Numerical Recipes" are
> untrustworthy. Early in 2009 on
> WWW.ACCU.org
> a review by myself which is almost ready for publication should be
> available.

The source for the Pascal version of Numerical Recipes can be found at
http://archives.math.utk.edu/software/msdos/numerical.analysis/nrpas13/.htm=
l

As the code for bessj0 is very short, translation to Ada is a small
exercise. On the other hand, the code seems to deal with only single
precision arithmetic so does not promise high accuracy.

Ken