Devon, Since I think of everything going forward from kindergarten (maybe someday we'll do more with prenatal education) I would use Y=: _2 + 0.5 * i.9" until the middle of the second year of algebra.
I really like your solution! It would be a great next step when teaching imaginary numbers. Linda -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Devon McCormick Sent: Monday, January 14, 2013 2:58 PM To: J-programming forum Subject: Re: [Jprogramming] atop continues to puzzle me Linda - a nice short cut for your expression "Y=: _2 + 0.5 * i.9" is "Y=: i:2j8". In general, providing the complex argument PjN to i: gives you N+1 points from -P to P. Regards, Devon On Mon, Jan 14, 2013 at 12:24 PM, Jose Mario Quintana < [email protected]> wrote: > 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 > -- Devon McCormick, CFA ^me^ at acm. org is my preferred e-mail ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
