To Henry: My apologies, the worst part is that I noticed the misspelling but I neglected to correct it; I guess watching the playoffs and writing to the forum do not mix very well.
To Linda: That is a nice feature; thanks for sharing it. One refreshing thing about J is that one never seems to stop learning it. Moreover, if one follows the forums and this one in particular one is shown (or reminded) how capable the J system really is. On Mon, Jan 14, 2013 at 3:10 AM, Linda Alvord <[email protected]> wrote: > Jose, Here's a simper version. Using the aspect ratio helps make the > derivative more obvious. I use Chrome and I don't know how this will look > elsewhere. > > Load 'plot' > u=: -: > v=: *: > Y=:_2 + 0.5 * i.9 > f=: 13 :'(] ; [:|:u@v d._2 _1 0 1 2 )y' > f > plot f Y > 'aspect 1'plot f Y > > Linda > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Linda Alvord > Sent: Sunday, January 13, 2013 9:21 PM > To: [email protected] > Subject: Re: [Jprogramming] atop continues to puzzle me > > load'plot' > > u=: -: > v=: *: > Y=: _2 + 0.01 * i.401 > f=: 13 :'(] ; [:|:u@v d._2 _1 0 1 2 )y' > f > ] ; [: |: u@v d._2 _1 0 1 2 > plot f Y > > If this is in a jijs and then run, it will shw the graph you expect bu t > it will provide a long J error message in a separate window. I don't know > how to prevent it. > > Also, maybe when u@v can be replaced by ([:u v)"v that will work also. > > Linda > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Jose Mario > Quintana > Sent: Sunday, January 13, 2013 5:17 PM > To: [email protected] > Subject: Re: [Jprogramming] atop continues to puzzle me > > To Raul: > >> I have no idea what "works reasonably well" means. > > That is a very subjective statement, apparently one can make use of > (@) and (@:) within the scope of (d.) but, of course, that depends on one's > point of view. > >> But consider also: >> >> AT=: 2 :0 >> u@v"v >> ) >> >> +:AT*: d. 1 >> 0 4x&p."0 0 0 >> +:@*: d. 1 >> 0 4x&p. > > This also happens for (at) and I was trying to point it out this difference > in my first message: > > " >> Rather works almost exactly? >> >> ('*'"_) @ ((+: @ *:) (d.1)) (0 1 2) >> * >> ('*'"_) @ ((+: at *:) (d.1)) (0 1 2) >> *** >> >> ((+: @ *:) (d.1)) b.0 >> _ _ _ >> ((+: at *:) (d.1)) b.0 >> 0 0 0 > " > > However, (d.) also treats differently (at) and (AT)! (See below.) > >> >> In both cases the rank of the left argument of d. is the same. So what >> we see here is that the rank of the result of d. depends on something >> other than the rank of its arguments. Have you found any documentation >> that describes the rank of the results of the d. >> conjunction? > > No, hence the words "seems arbitrary" in > >> and (@:) works reasonably well, although the rank change from 0 to _ >> seems arbitrary, but it stumbles for (at) and ([:), > > To Linda: > >> Jose, I'm working on your plot program and I found a ray of hope... > > Raul's (AT), unlike (at), does the job of plotting the functions: > > plot @: (] ; |: @: ((u AT v) d. _2 _1 0 1 2)) Y > > although in a different fashion, at least for the fixed version according to > the interpreter: > > plot @: (] ; |: @: ((u AT v)f. d. _2 _1 0 1 2)) Y > plot @: (] ; |: @: ((u @ v)f. d. _2 _1 0 1 2)) Y > > (u AT v)f. d. _2 _1 0 1 2 > (0 0 0 0 1r24&p."0 0 0 , 0 0 0 1r6&p."0 0 0 , -:@*:"0 0 0 , ["0 0 0 , > 1"0"0 0 0)"0 > (u @ v)f. d. _2 _1 0 1 2 > (0 0 0 0 1r24&p. , 0 0 0 1r6&p. , -:@*: , [ , 1"0)"0 > > Although so far it has not been confirmed, there is plenty of evidence that > (d.) attracted some bugs; Raul's (at) and ([:) do not work well in this > context but they should have worked. > > It seems to me that you would like to use (2 : '([: u v)"v') instead of (@) > because the former is more clear to you. But I would like to second Henri's > advice, if you understand (2 : '([: u v)"v') then you understand (@). Why > would you like then to use a long hand, so to speak, instead of a short hand > (besides, as this thread shows, (@) is more reliable)? Similar comments, > but to lesser extent, apply to ([:) vs. (@:). > > ________________________________________________________________________ > > On Sun, Jan 13, 2013 at 12:06 PM, Raul Miller <[email protected]> wrote: >> On Sun, Jan 13, 2013 at 10:26 AM, Linda Alvord >> <[email protected]> > wrote: >>> It seems to need d."0 but I can't seem to figure how to do it. >> >> You can use "0 on the result of d. For example: >> >> (d. 1) (" 0) >> >> I do not think you should have to do this, but it works. >> >> -- >> Raul >> ---------------------------------------------------------------------- >> 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
