Re: GP interface for computing Artin L functions

[Bill Allombert <Bill.Allombert@math.u-bordeaux.fr>]

On Thu, Oct 22, 2015 at 06:03:41PM +0200, Xavier Roblot wrote:
> > Does such L functions satisfy a functional equation compatible with the lfun
> > interface ? 
> 
> Well, I am not sure about that. But, usually, the way to do it is to compute
> the value of the primitive L-function and then multiply it by the right
> factor that is relatively easy to compute. In fact, I think I could even
> probably write the corresponding code if I have your blessing ;)

The issue is that the lfun interface only handles L functions with standard
functional equation. 
lfunartin only returns a ldata structure and does not compute values by itself.
There is no provision in a ldata structure to handle function with missing
Euler factors.

However you can use the private function artin_badprimes to get the list
of Euler factor for bad primes and the functions dirartin for good primes.

Cheers,
Bill.