Use of C99 extra long double math functions after r236148

[Stephen Montgomery-Smith]

On 07/09/2012 12:02 AM, Steve Kargl wrote:

> Yep.  Another example is the use of upward recurion to compute
> Bessel functions where the argument is larger than the order.
> The algorithm is known to be unstable.

By upward recursion, do you mean equation (1) in 
http://mathworld.wolfram.com/BesselFunction.html?

So what do people use.  Maybe something like 
http://en.wikipedia.org/wiki/Bessel_function#Asymptotic_forms (second 
set of equations), but finding some asymptotics with a few extra terms 
in them?