128!:5 is similar to the isnan function in many other languages. http://www.google.com/search?hl=en&q=isnan , 4,630,000 hits. A good reason for calling 128!:5 "Is NaN".
----- Original Message ----- From: Roger Hui <[EMAIL PROTECTED]> Date: Friday, February 29, 2008 6:26 Subject: Re: [Jbeta] Use of the name 'NaN' deprecated To: Beta forum <[email protected]> > More precisely, NaN denotes many bit patterns in the IEEE standard. > J displays them all as _. and 128!:5 is 1 for each of them. > On input into J, _. is converted into a single one of such > patterns. > Thus: > > hex =: ([EMAIL PROTECTED]) }. 2&(3!:3) > unhex=: 3!:2 @ ((}: 2 (3!:3) 0.5) , ]) " 1 > > H=: '0123456789abcdef' > > hex _. > fff8000000000000 > > ] t=: 'fff8',"1 H{~7 12 [EMAIL PROTECTED] 16 > fff87acee515487a > fff80d41773eb545 > fff8006d81d67daf > fff869b83bf61c7a > fff87ac325f456a2 > fff8b2444f99e537 > fff81e712ef5847e > unhex t > _. _. _. _. _. _. _. > t -: hex unhex t > 1 > 128!:5 unhex t > 1 1 1 1 1 1 1 > > > > ----- Original Message ----- > From: Don Guinn <[EMAIL PROTECTED]> > Date: Friday, February 29, 2008 4:23 > Subject: Re: [Jbeta] Use of the name 'NaN' deprecated > To: Beta forum <[email protected]> > > > There are many other values in the IEEE standard which > represent invalid > > numbers other than NaN. How does 128!:5 treat them? Does it > treat them all > > as NaN or as numbers? ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
