I think you are replying to a different argument than the one I was trying to make.
I wasn't suggesting that _. be 'above that' in the sense of following certain J-defined rules independent of the IEEE spec. That would be OK but if it's too hard, let it go. I am happy with all the implementation decisions you have made. I am particularly happy with raising error when _. would be created. My only objection is to using the name 'NaN'. Maybe you use a NaN for _., but I see no reason to pollute the documentation with that term. I AM suggesting that the language spec be 'above that', because NaN is a new and unnecessary concept within J numbers. And _. IS a number. qbeta tells me so: 9!:14'' j602/beta/2008-02-22/22:30 3!:0 (_.) 8 Don't change a line of code. Do change the doc of 128!:5 to say it checks for the presence of _. rather than of NaN. Do change 'NaN error' to either 'domain error' (preferred) or '_. error' . The only appearance of NaN in the docs should be the one in _., which is The indeterminate _. is provided to aid in dealing with NaN (not a number) in data from external sources... This makes clear that NaN is IEEE, not J. Occam's razor. Henry Rich > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Eric Iverson > Sent: Sunday, February 24, 2008 12:08 PM > To: Beta forum > Subject: Re: [Jbeta] Use of the name 'NaN' deprecated > > Your saying _. is indeterminate and has nothing to do with > the IEEE spec of > Nan doesn't make it so. Our conclusions are that trying to > make J 'above > that' is a fools game that has a very high performance cost > for all fp > operations. The hard, unavoidable fact is that J uses the > IEEE fp spec as > provided by the hardware and compiler. To do otherwise is not > worth the > effort and has far too high a cost. > > If you are interested and concerned about _. (whatever it is > called), I > strongly suggest you take a look at what is in the current > beta as that is > what is going to be in the release. > > ----- Original Message ----- > From: "Henry Rich" <[EMAIL PROTECTED]> > To: "'Beta forum'" <[email protected]> > Sent: Sunday, February 24, 2008 11:47 AM > Subject: [Jbeta] Use of the name 'NaN' deprecated > > > > Roger and Eric have referred to NaN in their messages. I suggest > > that this usage should be avoided. > > > > NaN is meaningful only in reference to the IEEE floating-point > > spec. > > > > J is above that. J deals with numbers. Floating-point is an > > implementation detail that should not be alluded to in the > > description of the language. > > > > _. is indeterminate. It is not NaN. For one thing, it is > > a number (at least it used to be - I haven't had the courage > > to move to rbeta yet), while NaN is explicitly not a number. > > And, there are many values and kinds of NaN, but only one > > indeterminate. > > > > So, NaNs in external sources produce unpredictable results. > > Use of _. produces unpredictable results. But they are > > not the same things. > > > > Henry Rich > > > >> -----Original Message----- > >> From: [EMAIL PROTECTED] > >> [mailto:[EMAIL PROTECTED] On Behalf Of Eric Iverson > >> Sent: Sunday, February 24, 2008 9:37 AM > >> To: Beta forum > >> Subject: Re: [Jbeta] issues not yet resolved > >> > >> I am sorry to say that we won't get fixes for these two > >> problems into this > >> release. We have just run out of time and need to get this > >> release out so we > >> can clear the decks for the next round of activities. The NaN > >> problem turned > >> into a surprisingly difficult mess and took much longer > than expected. > >> > >> Your two bugs will be at the top of the list for 602. > >> > >> ----- Original Message ----- > >> From: "bill lam" <[EMAIL PROTECTED]> > >> To: "Beta forum" <[email protected]> > >> Sent: Saturday, February 02, 2008 12:05 AM > >> Subject: [Jbeta] issues not yet resolved > >> > >> > >> > [Jbeta] for-loop, continue, switch-case 30 Sep 2007 > >> > > http://www.jsoftware.com/pipermail/beta/2007-September/002383.html > >> > > >> > [Jbeta] m&i. and boxed unicode 30 Sep 2007 > >> > > http://www.jsoftware.com/pipermail/beta/2007-September/002382.html > >> > > >> > Will they be fixed? > >> > > >> > ---------------------------------------------------------------------- > >> > For information about J forums see > >> 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 > ---------------------------------------------------------------------- > For information about J forums see > http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
