The author ought to be interested to know this. His paper exhibits a quantum-computer algorithm for Key, so it's good to know its history.
A current research thrust is to develop useful algorithms for quantum computers out of the notional ones which have existed to-date, like the Deutsch-Josza Algorithm (DJA). http://en.wikipedia.org/wiki/Deutsch%E2%80%93Jozsa_algorithm The DJA itself is trivial, almost absurdly so. But it points the way, in the sense that XOR, say, points the way to practical arithmetic. All this of course is intended to motivate the development of operational quantum computers. This makes the author a sort of latter-day Lady Ada Lovelace, one could say. On Wed, May 18, 2011 at 6:44 PM, Roger Hui <[email protected]> wrote: > Although the APL90 paper > http://www.jsoftware.com/papers/J1990.htm > does not refer to "key", I tried some "key" > expressions just now in the J1990 shareware > version distributed at APL90, and I got: > > 1 1 2 1 3 </. 'abcde' > ┌───┬─┬─┐ > │abd│c│e│ > └───┴─┴─┘ > 1 1 2 1 3 +//. 100*1 2 3 4 5 > 700 300 500 > > So "key" was introduced quite early, sometime > between the submission of final copy for APL90 > and the time of the conference, August 13-17, 1990. > > > > ----- Original Message ----- > From: Roger Hui <[email protected]> > Date: Tuesday, May 17, 2011 19:06 > Subject: Re: [Jprogramming] Aggregation > To: Programming forum <[email protected]> > >> The cited article has the passage: >> >> The key adverb was not in the initial version of J. >> It came in later at the request of the J user community, >> notably Joey Tuttle. >> >> This is not consistent with what I remember. >> I first saw the idea in the 1980s in >> the documentation for the Connection Machine, >> http://en.wikipedia.org/wiki/Connection_Machine >> which had a machine instruction for doing >> x f//.y for a small set of functions f and certain x's. >> In any case, the October 1990 dictionary >> had u/. with the same definition as now. >> (The earliest public version of J, available >> at APL90, was dated July 1990. >> http://www.jsoftware.com/papers/J1990.htm >> That version did not have "key".) >> >> In any case, it is true that many case of the >> special code for u/. are "JKT specials", >> implemented in response to code Joey posted >> or in expectation that they would be useful >> for what he does. >> >> >> >> ----- Original Message ----- >> From: "Lettow, Kenneth" <[email protected]> >> Date: Tuesday, May 17, 2011 17:37 >> Subject: Re: [Jprogramming] Aggregation >> To: Programming forum <[email protected]> >> >> > Ian, >> > >> > I best understood key after reading a book you edited ;-) >> > >> > To summarize... http://www.jsoftware.com/jwiki/Doc/Articles/Play151 >> > >> > All the best, >> > >> > Ken >> > >> > -----Original Message----- >> > From: [email protected] >> > [mailto:[email protected]] On Behalf Of Ian Clark >> > Sent: Tuesday, May 17, 2011 5:09 PM >> > To: Programming forum >> > Subject: [Jprogramming] Aggregation >> > >> > I'm being lazy here. But I need a better answer than I can >> devil out >> > myself. It occurs in a recent submission to Vector... >> > >> > I have an array like this (which may be unsorted, and can grow very >> > large): >> > >> > 1 100 >> > 1 100 >> > 1 20 >> > 1 400 >> > 2 30 >> > 2 200 >> > 2 300 >> > 33 100 >> > 33 100 >> > 33 100 >> > >> > I want to collapse it to: >> > >> > 1 620 >> > 2 530 >> > 33 300 >> > >> > i.e. summing over subheadings. >> > The original example had A B C in place of 1 2 33, but >> > numbers will >> > do, to save boxing. We don't know the full set of A B C ... in >> > advance. Nothing to be assumed about the first column, except >> it is >> > +ve integers. But I'm also interested in the case where the first >> > column lies in the set: i.(n) for some n>0. In other words >> they >> > can be >> > squashed up. >> > >> > 1. There's simply got to be a "jem" to do it. Suggestions, please. >> > - Transpose the array if you wish. Box it: 1 100 ; 1 100 >> ; 1 20 >> > ; ... >> > -whatever. >> > - No, of course I don't want a looping solution :) >> > >> > 2. What do you call this process? I call it "aggregation" -- >> but I >> > think the name differs across disciplines. > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
