On 05/18/2012 10:43 AM, Jonathan Taylor wrote:
In the documentation, there are no specifications for the values of nu in
the evaluation of bessel_Jnu. However after running the command for nu< 0,
a domain error was shot at me. After looking at the source code, it indeed
shows that a domain error is thrown when nu< 0.
I wasn't entirely sure from your message whether you know the relationship between
nu>0 and nu<0, but for Bessel functions of the first kind there is a very
simple relationship - see
http://mathworld.wolfram.com/BesselFunctionoftheFirstKind.html equation 51.
For non-integer nu, J(nu,x) and J(-nu,x) are not related by the above
formula, rather
there is an imaginary part proportional to sin(nu x) Y(nu,x). It can be
obtained easily
from Abramowitz+Stegun 9.1.3, 9.1.4, and 9.1.6.
If you happen to want integer values of nu, use the bessel_Jn functions
rather than bessel_Jnu.
--
G. Jungman
