[SciPy-user] jn & lpmn or sph_jn...

Robert Kern robert.kern at gmail.com
Wed Aug 2 16:17:54 CDT 2006


fred wrote:
> David Huard a écrit :
>> I hope someone else will find a better answer to your question, but here
>> is something you could try if you are really hungry for speed.
> 
> [snip]
> 
> Ok, thanks for the hint, I'm working on it.
> 
> However, I would like to see how jn(n,x) is written.
> I did not find nothing about it (no "def jn:"), except the fact that
> jn(n,x) is written in C, in cephes/.
> But I did not find out how the interface C/python is written, as in
> fortran (source specfun.f -> specfun.pyf -> basic.py).
> I'm going on the bad way ?

It is a ufunc, so it is created by calling PyUFunc_FromFuncAndData in 
Lib/special/_cephesmodule.c . The actual implementation of the math-bits is in 
Lib/special/cephes/jn.c .

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco


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