Re: bug? (1/13+O(10^2))^(1/3) triggers an endless loop

[Joerg Arndt <arndt@jjj.de>]

Thanks verybody!  I just put the snippet
n=99; Vecrev(digits(lift(chinese( Mod((1/13+O(5^n))^(1/3), 5^n), Mod((1/13+O(2^n))^(1/3), 2^n)))))
into https://oeis.org/draft/A319741
(which should be published as https://oeis.org/A319741 soon).

Best regards,   jj


* Dirk Laurie <dirk.laurie@gmail.com> [Oct 29. 2018 13:36]:
> One can do the computation itself this way:
> 
> ? chinese( Mod((1/13+O(5^2))^(1/3),5^2), Mod((1/13+O(2^2))^(1/3),2^2))
> %1 = Mod(53, 100)
> 
> Op Ma., 29 Okt. 2018 om 11:08 het Karim Belabas
> <Karim.Belabas@math.u-bordeaux.fr> geskryf:
> >
> > * Joerg Arndt [2018-10-29 09:05]:
> > > The following input appears to take forever:
> > > (1/13+O(10^2))^(1/3)
> >
> > This is expected, n-adics for non prime n are not supported (although a few
> > trivial operations will actually work) :
> >
> > (10:04) gp > ??t_PADIC
> > p-adic numbers (t_PADIC)::
> >
> >    Typing O(p^k),  where p is a prime and k is an integer, yields a p-adic 0 of
> > accuracy k, representing any p-adic number whose valuation is >= k. [...]
> >
> >    Note  that  it  is  not  checked  whether  p is indeed prime but results are
> > undefined if this is not the case: you can try to work on 10-adics if you want,
> > but  disasters  will  happen  as  soon  as  you do something non-trivial.
> >
> >
> > Cheers,
> >
> >     K.B.
> > --
> > Karim Belabas, IMB (UMR 5251)  Tel: (+33) (0)5 40 00 26 17
> > Universite de Bordeaux         Fax: (+33) (0)5 40 00 21 23
> > 351, cours de la Liberation    http://www.math.u-bordeaux.fr/~kbelabas/
> > F-33405 Talence (France)       http://pari.math.u-bordeaux.fr/  [PARI/GP]
> > `
> >