Bessel function

[Dar Scott]

On Aug 6, 2006, at 4:03 AM, Stephen King wrote:

> If not, does anyone have any suggestions on the maths to build this  
> function.

Can you get by with integral orders?  Is there a limit on how big the  
arg is?

I would think you can compute it for positive integer orders using a  
Taylor's series.  See wikipedia for Bessel.  Getting the negative  
order from the positive is described there, too.

In computing the Taylor's series, don't compute the power or the  
factorials each time, but accumulate those as you go.

If you need only one order and you call it often, you can build a  
factor table the first time and use that each time.


Dar Scott