Bobby Gutierrez needed some Bessel function
for some purpose and wrote an undocumented helper
program. I can't remember which and can't find
the code.
I once wrote a rather specific Stata program for I_0,
not what you specify here.
1.5708 means _pi/2 here.
Odds are you need to transliterate formulae
from Abramowitz and Stegun's handbook to Stata or Mata.
Nick
n.j.cox@durham.ac.uk
Jhilbe@aol.com
> To be more specific, has anyone made a Bessel of the 2nd
> kind function in
> Stata? An approximation is sqrt(1.5708/x) *
> sin(x-0.7854(2y+1)) for values
> closer to the max values and
> -[ (2^n)(n-1)! /pi ] * x^(-n) for values closer to 0. If
> someone has a
> better approximation, or the "exact" function in Stata, I'd
> love to see it.
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