Re: probable bug of "ispower" function in GP: FALSE, apologies!

[luis.gallardo@math.cnrs.fr]

Hi Bill,


Apologies!

I misunderstood the definition of "ispower"!


I wanted a function that identify directly if some integer is a power of 2


cordially,


luis
***



luis.gallardo@math.cnrs.fr a écrit :

> Brest, January 12, 2023.
>
> Hi Bill,
>
> While working on a problem I landed at:
>
> Reading GPRC: gprc.txt
> GPRC Done.
>
>                                                                       
>                 GP/PARI CALCULATOR Version 2.15.0 (released)
>                                                                       
>         amd64 running mingw (x86-64/GMP-6.1.2 kernel) 64-bit version
>                                                                       
>          compiled: Sep 19 2022, gcc version 10-posix 20210110 (GCC)
>                                                                       
>                           threading engine: single
>                                                                       
>                (readline v8.0 enabled, extended help enabled)
>
>                                                                       
>                    Copyright (C) 2000-2022 The PARI Group
>
> PARI/GP is free software, covered by the GNU General Public License,  
> and comes WITHOUT ANY WARRANTY WHATSOEVER.
>
> Type ? for help, \q to quit.
> Type ?18 for how to get moral (and possibly technical) support.
>
> parisize = 8000000, primelimit = 500000
> (01:00) gp > ispower(8,2)
> %1 = 0
> (01:00) gp > ispower(16,2)
> %2 = 1
> (01:00) gp > ispower(9,3)
> %3 = 0
> (01:00) gp > ispower(27,3)
> %4 = 1
> (01:01) gp > ispower(4,2)
> %5 = 1
> (01:01) gp >
>
>
> ***
> I checked other versions of GP, including a linux one:
>
> same problem!
>
> Cordially,
>
> luis
> ***
>
> Lis H. Gallardo
>
>
> Bill Allombert <Bill.Allombert@math.u-bordeaux.fr> a écrit :
>
> > On Sat, Oct 15, 2022 at 11:05:56AM +0200, luis.gallardo@math.cnrs.fr wrote:
> > > Hi,
> > >
> > > Nice new version!
> > >
> > > What about to add some basic versions of sum and prod?
> > >
> > > sum by steps
> > >
> > > prod by steps
> >
> > Hi Luis,
> >
> > Could you give an example ?
> >
> > Thanks for using PARI/GP!
> > Bill.