Re: Finding bitprecision

On Tue Dec, 19th, 2023 at 09:08, Aurel Page wrote:

> This is the time to create 1. at your precision, not the time to find
> the bitprecision.
>
> ? my(s=0,p=10^4); localprec(p); for(n=1,10^5,a=1.; s+=p);
> time = 74 ms.
> ? my(s=0,p=10^6); localprec(p); for(n=1,10^5,a=1.; s+=p);
> time = 2,718 ms.
>

    Indeed, however I think Ilya asked why there is no way to know the
  local bit precision without creating an object which require time to
  create.

     You can install(get_localbitprec,l), for a workaround:

? install(get_localprec,l)
? localbitprec(1000);get_localprec()
%2 = 18
? localbitprec(10000);get_localprec()
%3 = 159

       Best,

             Loïc



> On 19/12/2023 07:20, Ilya Zakharevich wrote:
> > Should not there be O(1) way to find the current localbitprecision()?
> >
> >    (22:17) gp > localprec(10000);   my(s); for(n=1,100000,
> s+=bitprecision(1.));
> >    time = 78 ms.
> >    (22:17) gp > localprec(1000000); my(s); for(n=1,100000,
> s+=bitprecision(1.));
> >    time = 2,121 ms.
> >
> > Thanks,
> > Ilya
>
>
>