Hmm...
Ok, so what I think this means is that if we do not want gcd to hang
forever on some arguments we would in effect need to use -.@= in
euclid's algorithm instead of ~:
Or, more specifically, in ve.c
D jtdgcd(J jt,D a,D b){D a1,b1,t;B stop = 0;
a=ABS(a); b=ABS(b); if(a>b){t=a; a=b; b=t;}
ASSERT(inf!=b,EVNAN);
if(!a)R b;
a1=a; b1=b;
while(remdd(a1/jround(a1/a),b1)){t=a; if((a=remdd(a,b))==0)break;
b=t;} // avoid infinite loop if a goes to 0
R a;
} /* D.L. Forkes 1984; E.E. McDonnell 1992 */
we should be testing for _. to avoid an infinite loop.
It might be sufficient to replace if((a=remdd(a,b))==0)break; with
if(!(a=remdd(a,b))!=0)break; (though it's possible that a compiler
might "optimize" that expression and break it).
But, this routine should either return a result or it should throw an error.
--
Raul
On Fri, May 6, 2022 at 7:26 PM Henry Rich <henryhr...@gmail.com> wrote:
>
> Just try adding _. + 4 .
>
> Henry Rich
>
> On 5/6/2022 6:47 PM, Raul Miller wrote:
> > Huh?
> >
> > My understanding was that the only acceptable sources of _. were:
> > direct entry, evaluation, 3!:n and DLL calls.
> >
> > And, that the only primitives which were allowed to produce results
> > containing _. were structural primitives which move data without
> > interpreting it.
> >
> > --
> > Raul
> >
> >
> >
> > On Fri, May 6, 2022 at 5:58 PM Henry Rich <henryhr...@gmail.com> wrote:
> >> No. _. + 4 is not a NaN error. _ - _ is NsN error.
> >>
> >> This result should be _. with no error.
> >>
> >> Henry Rich
> >>
> >> On 5/6/2022 5:55 PM, Raul Miller wrote:
> >>> Sure, but that's not prescriptive here.
> >>>
> >>> Here, we have a case where there is no result because _.
> >>> (approximately speaking) gives an unhandled infinity as an
> >>> unrecognized loop condition.
> >>>
> >>> My gut feeling is that this means that we should treat this as an
> >>> example of a case where the result would be _. if we could compute it
> >>> (which means that we should throw a NaN error).
> >>>
> >>> Thanks,
> >>>
> >>
> >> --
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