Lets say you expect to get results of some operations into a matrix a or b a=.3 4$1 2 3 4 5 6 _. 6 3 4 2 3 b=.3 4$1; 2; 3; 4; 5; 6; 'domain error'; 6; 3; 4; 2; 3 a=_. 0 0 0 0 0 0 1 0 0 0 0 0 b=<'domain error' 0 0 0 0 0 0 1 0 0 0 0 0
getting a is pretty straight forward because the operations would all work and one would give _. as an answer getting b to work is not as plain because you would need to put up a trap to catch the domain error otherwise the processes stop on the domain error. 2008/2/7, Kip Murray <[EMAIL PROTECTED]>: > > I think _. as an answer signals the question didn't make sense. As _. > is _not a number_ (it could be Lucciano Pavarotti's high C), operations > like x + _. and x >. _. are undefined. Another user could be depending > on _. as a signal the operation was undefined. > > Of course, depending on _. for anything can be questioned, and you can > ask why _ , which also is not a number, gets special treatment. The > difference is, we know what rules _ obeys. See for example The Extended > Real Number System, Section 1.23 of Walter Rudin's Principles of > Mathematical Analysis, Third Edition. > > Kip Murray > > On Thu, 7 Feb 2008, Henry Rich wrote: > > (Note that the subject of the original message contained > a typo <. for >., though the text was correct.) > > I don't see the logic. x+_. > is _. because if you don't know what _. is, you don't > know the result, even if x is _ . But with _ >. _. > you know the result, no matter what _. is: _ >. x > is _ for all x. So _ would be a reasonable answer. > > You said earlier that _. <: _ should produce 1, > which seems to conform to my argument above. If > _. is recognized as less-or-equal _, I think it > needs to follow that _. >. _ is _ . > > The case that got me into this _. mess was > > 1 2 3 _ I. _. > > where I had a list that I thought I had terminated with a > high value, but I found that _. is higher yet. It > would simplify analysis and description if _. were > consistently recognized as not being bigger than _ . > > Henry Rich > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf Of Roger Hui > > Sent: Wednesday, February 06, 2008 10:45 PM > > To: Beta forum > > Subject: Re: [Jbeta] Another incompatibility: _ <. _. > > > > The answer should be _. for the same reason that x+_. should be _. . > > That is, for all numeric atoms x, _. should be the answer for > > > > x + _. > > x >. _. > > x <. _. > > _. + x > > _. >. x > > _. <. x > > > > > > > > ----- Original Message ----- > > From: Henry Rich <[EMAIL PROTECTED]> > > Date: Wednesday, February 6, 2008 6:55 > > Subject: [Jbeta] Another incompatibility: _ <. _. > > To: 'Beta forum' <[email protected]> > > > > > I also just got bit by > > > > > > _ >. _. > > > _. > > > > > > This gave _ in 601. And in 602, > > > > > > _. >. _ > > > _ > > > > > > > > > I think both results should be _ > > ---------------------------------------------------------------------- > > For information about J forums see > > http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > > > Kip Murray > > [EMAIL PROTECTED] > http://www.math.uh.edu/~km > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > -- Björn Helgason, Verkfræðingur Fugl&Fiskur ehf, Þerneyjarsund 23, Box 127 801 Grímsnes ,t-póst: [EMAIL PROTECTED] Skype: gosiminn, gsm: +3546985532 Landslags og skrúðgarðagerð, gröfuþjónusta http://groups.google.com/group/J-Programming Tæknikunnátta höndlar hið flókna, sköpunargáfa er meistari einfaldleikans góður kennari getur stigið á tær án þess að glansinn fari af skónum /|_ .-----------------------------------. ,' .\ / | Með léttri lund verður | ,--' _,' | Dagurinn í dag | / / | Enn betri en gærdagurinn | ( -. | `-----------------------------------' | ) | (\_ _/) (`-. '--.) (='.'=) `. )----' (")_(")
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