evaluating erf(%i) in maxima



Raymond Toy writes:
>>>>>>"Vadim" == Vadim V Zhytnikov  writes:
> 
> 
>     Vadim> I just want to remind that quite a bit ago you promised
>     Vadim> to take a look at gamma-lanczos for gamma function at
>     Vadim> complex argument.  gamma-lanczos code is already hare
> 
> Did I?  My apologies for having forgotten!
> 

No problems.

> What was the issue?  That we don't evaluate gamma function for complex
> args?  This is mostly like because no one added the appropriate
> knowledge to gamma to recognize complex numbers.
> 

It would be great to have complex gamma in 5.9.2 -  gamma-lanczos
is in the csimp2.lisp.

>     Vadim> In general I still don't understand what is preferred way
>     Vadim> to calculate complex valued expression involving
>     Vadim> elementary or special functions numerically?
>     Vadim> It seems that rectform is required for expression with
>     Vadim> elementary functions.  Is is so for special functions.
> 
>     Vadim> Which special functions can be evaluated numerically
>     Vadim> by Maxima CVS?  At real arguments? At complex arguments?
> 
> As a initial answer, maxima doesn't know how to evaluate special
> functions at complex args. :-(  But there are exceptions of course.
> 
> Ray
> 


-- 
      Vadim V. Zhytnikov