This seems to be my case, ha ha! I am now retired, but in the 70's I used APL a lot. ----- Original Message ----- From: "Björn Helgason" <[email protected]> To: "Programming forum" <[email protected]> Sent: Friday, November 04, 2011 12:39 PM Subject: Re: [Jprogramming] Newbie question
>I guess it takes a long time for anyone to realize the power of rank. > > https://groups.google.com/forum/?hl=is#!searchin/j-programming/rank/j-programming/XwvPm9UhCt8/lMyXcnT_6wIJ > > Some people claim that if you do not understand rank you do not > understand J > > 2011/11/4 Roger Hui <[email protected]> > >> When "table" x f/y was introduced (at the very beginning) we did not >> fully comprehend the power of the rank operator. If I had realized >> that table was just x f"(lr,_) y, where lr is the left rank of f, I >> might have tried to argue strongly for using the dyad f/ for something >> else. >> >> >> >> On Fri, Nov 4, 2011 at 2:15 AM, Henry Rich <[email protected]> wrote: >> > Just a quibble with terminology: 'item' means _1-cell. That concept >> > does not apply here. If you define 'l-cell' to be the left rank of the >> > verb, and 'r-cell' the right rank, you could say >> > >> > ...it loops through all the l-cells of x, then for each of those, all >> > the r-cells of y... >> > >> > Henry Rich >> > >> > On 11/4/2011 12:13 AM, Marshall Lochbaum wrote: >> >> * has rank 0 already, so it isn't necessary. The definition of / is >> that it >> >> applies the verb with rank (left rank),_ . Essentially, this means >> >> that >> it >> >> loops through all the items of x, then for each of those, all the >> >> items >> of >> >> y, where an "item" is an item with the left rank of the verb. If you >> >> try >> >> magic/~ a with magic having rank _ (because it's a fork), you just get >> (a >> >> magic"_ _"_ _ a), which simply applies magic regularly. >> >> >> >> Marshall >> >> >> >> On Thu, Nov 3, 2011 at 11:57 PM, Ricardo >> >> Forno<[email protected] >> >wrote: >> >> >> >>> I have this verb: >> >>> magic =: * %>:@(+:@*) - + >> >>> that I use only as a dyad, and, say, >> >>> a =: 0.1 * i. 10 >> >>> If I want to get a table of the * verb, I write: >> >>> a * / a >> >>> If I write >> >>> a magic / a >> >>> I dont get a table. To get a table, I have to write: >> >>> a magic"0 / a >> >>> Why is it so, since both * and magic may be used as dyads? >> >>> Thanks. >> >>> >> >>> >> >>> ---------------------------------------------------------------------- >> >>> 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 >> > > > > -- > Björn Helgason, Verkfræðingur > Fornustekkum II > 781 Hornafirði, > t-póst: [email protected] > gsm: +3546985532 > twitter: @flugfiskur > 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 | > ( -. | `-----------------------------------' > | ) | (\_ _/) > (`-. '--.) (='.'=) ♖♘♗♕♔♙ > `. )----' (")_(") ☃☠ > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
