in this case, the issue has to do with _ and __ not having equivalents in extended numbers, and I'm unsure its possible to create one. MAXINT doesn't help if we don't want to conver 1000 bit numbers to 64 bits.
So, the override to make is to test for one argument being _ or __ . That is probably already done in the implementation after converting to float, and returning the other argument (with origninal type) could be done instead. Though my assumption about _ seems wrong. There is a x: representation for it. 3!:0 (3!:2) (3!:3) x: _ 128 in which case the &x: adverb seems appropriate to me. ________________________________ From: Raul Miller <[email protected]> To: Programming forum <[email protected]> Sent: Wednesday, February 3, 2016 3:09 PM Subject: Re: [Jprogramming] When a <. _ is less than a Actually, I don't care about coercing floating point to integer - just boolean to integer. And, this is just a model. So: MAXINT=: +/1,(#~1-2&|)".":x:+:^:(4>:3!:0)^:a:1 MININT=: _1-MAXINT setype=:dyad define select. x case. 1 do. 0~:y case. 4 do. <.MININT>.y<.MAXINT case. 8 do. y<._ case. 64 do. <.x:y case. 128 do. (1r2*2r1)*x:y case. do. throw. end. ) BIDZXQ=: adverb define u y : type=. x >.&(3!:0) y x u&(type&setype) y ) Known problems: * setype fails for type 4 for some values (like: MAXINT-432.1) * does not currently support literal, boxed nor sparse types * not tested cross-platform * maybe could use a different name Example use: 1.1 + BIDZXQ 1r2 8r5 -- Raul On Wed, Feb 3, 2016 at 2:39 PM, Raul Miller <[email protected]> wrote: > I think, in this case, that we are working against the language > definition. That tends to introduce quirks and other problems into the > language. > > Specifically, I think we would be working against > http://www.jsoftware.com/help/dictionary/dictg.htm and the table > introduced by the phrase "Dyadic verbs (e.g. + - * % , = <) that > require argument type conversions". > > So, rather than introducing a special case which requires inspection > of arguments, maybe the right thing to do is to define an adverb which > implements a different type conversion table on behalf of whatever > verb it's working with? > > That said, I set out to write such a thing, and got stalled when > trying to figure out how reliably and efficiently coerce a floating > point array to integer type. > > Specifically: > > MAXINT=: +/1,(#~1-2&|)".":x:+:^:(4>:3!:0)^:a:1 > MININT=: _1-MAXINT > > 3!:0 MAXINT,MININT > 4 > 3!:0 <.MININT>.( MAXINT+0.01)<.MAXINT-1 > 8 > > Basically, I'm not sure how to deal with this existing quirk: > > x:MAXINT > 9223372036854775807 > x:( MAXINT-0.01)<.MAXINT-511 > 9223372036854775808 > 9!:14'' > j804/j64/darwin/release/commercial/www.jsoftware.com/2015-12-21 18:06:25 > > Any suggestions? > > Thanks, > > -- > Raul > > > On Wed, Feb 3, 2016 at 2:02 PM, Dan Bron <[email protected]> wrote: >> I know we have yet to organize a formal process for building and >> disseminating a community-driven implementation of J, but in anticipation of >> that day’s arrival, perhaps we can start collecting community-driven >> proposals for enhancements? >> >> One such enhancement could be special code that detects whether the argument >> to an arithmetic dyad is the scalar _ (or __ or _.) and if so, avoids >> demoting the other argument to double if it’s already extended or rational. >> >> I have other ideas too. But maybe we should collect them on the Wiki? >> >> -Dan >> >> >>> On Feb 2, 2016, at 9:12 PM, Henry Rich <[email protected]> wrote: >>> >>> No, extendeds promote to float on mixed operations. >>> >>> Henry Rich >>> >>> On 2/2/2016 9:09 PM, 'Pascal Jasmin' via Programming wrote: >>>> 9223372036854736345 <. _ >>>> 9.22337e18 >>>> >>>> result is a double. <. double is the closest integer it can find. >>>> >>>> this seems like a problem though: >>>> >>>> >>>> 9223372036854736345x <. _ >>>> 9.22337e18 >>>> >>>> >>>> >>>> ----- Original Message ----- >>>> From: Henry Rich <[email protected]> >>>> To: Programming forum <[email protected]> >>>> Sent: Tuesday, February 2, 2016 9:05 PM >>>> Subject: [Jprogramming] When a <. _ is less than a >>>> >>>> I'm stepping up to the world of 64-bit integers, and stepping into >>>> cowflops. >>>> >>>> This took me quite a while: >>>> >>>> <. 9223372036854736345 <. _ >>>> >>>> 9223372036854735872 >>>> >>>> >>>> See that? Take the minimum of (number) and (infinity), and the result >>>> is less than (number)! >>>> >>>> Yes, I understand why it happens. Now I do. Be warned. >>>> >>>> Henry Rich >>>> ---------------------------------------------------------------------- >>>> 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 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
