Since the only way to "natively" generate _0 in J is through %__, is it worthwhile to put a check in % for __ and remove checks elsewhere? (e.g. in i. or -:)? Of course, _0 could be introduced from the outside, in memory mapped file or something, but caveat emptor, etc.
-Dan -----Original Message----- From: programming-boun...@forums.jsoftware.com [mailto:programming-boun...@forums.jsoftware.com] On Behalf Of Roger Hui Sent: Wednesday, January 16, 2013 9:10 PM To: Programming forum Subject: Re: [Jprogramming] Hermitian from triangular Among other things, _0 is a pain in the neck in the dyad i. with hashing. Also louses up straightforward algorithms for the dyad -:!.0 . On Wed, Jan 16, 2013 at 3:38 PM, Henry Rich <henryhr...@nc.rr.com> wrote: > Negative zero makes sense as a last vestige of gradual underflow; and > anyway, it's well-behaved: it looks like 0 except when you take the > log, reciprocal, or square root. In any normal computation, it goes > away. In contrast, NaN messes up anything it touches. > > I think we've had negative 0 in J forever. If NaN is a data virus, -0 > is a virus that has been inserted into our DNA. > > Henry Rich > > On 1/16/2013 4:45 PM, Raul Miller wrote: > >> On Wed, Jan 16, 2013 at 4:35 PM, Henry Rich <henryhr...@nc.rr.com> wrote: >> >>> Negative zero isn't a bug, it's a feature that numerical types, >>> especially William Kahan, wanted to get into IEEE-754 to help out >>> some things. I'm not expert enough to explain. >>> >> >> Something similar could be said about NaN. >> >> ------------------------------**------------------------------** > ---------- > For information about J forums see > http://www.jsoftware.com/**forums.htm<http://www.jsoftware.com/forums. > htm> > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
