Re: ispolygonal

[Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>]

On Wed, May 09, 2012 at 02:20:52PM +0200, Karim Belabas wrote:
> * Bill Allombert [2012-05-08 23:34]:
> > I am experimenting with ispolygonal:
> > 
> > ? ispolygonal(36,2)
> >   ***   at top-level: ispolygonal(36,2)
> >   ***                 ^-----------------
> >   *** ispolygonal: incorrect type in ispolygonal (t_INT).
> > 
> > This is confusing since 2 is a t_INT.
> 
> The rationale was to avoid the e_MISC error type [ which is essentially
> impossible to trap cleanly ], and consider that the expected input
> "type" was 'a t_INT in Z_{> 2}'.
> 
> This is a bit far-fetched and potentially confusing, I temporarily changed
> it to e_MISC.
> 
> Presumably we need a general error type for "violated inequality" ?
> 
>   pari_err(e_INEQ, "ispolygonal", "s > 2", s);

We could define
pari_err(e_TOOSMALL,"ispolygonal",s,gen_2)
    --> "%s: %Ps must be > %Ps"
In practice I expect this would cover almost all case and allow the user
to retrieve the inequality.

Cheers,
Bill.