+/(* %.) 2 3 4 1 (% %.) 2 3 4 29 29 29 This gives me enough information to understand what monadic %. did.
Den 21:20 onsdag den 23. april 2014 skrev Raul Miller <rauldmil...@gmail.com>: To my knowledge, J602 is still the best place for labs. > >To fix that, I imagine we need some people (who have experience writing >labs) to tackle porting the lab mechanisms to newer versions of J. It's not >going to be perfect, though, especially in the initial attempts. > >Mostly, I think it's a matter of someone having the interest and drive to >do it. We have more than enough talent here to offer advice when problems >arise. (And sometimes that advice might even be correct.) > >Thanks, > >-- >Raul > > > >On Wed, Apr 23, 2014 at 3:10 PM, robert therriault ><bobtherria...@mac.com>wrote: > >> Hey Raul, >> >> The subject of my conference talk was going to be jsoftware.com as a >> learning ecology and labs are a big part of that (and could become bigger). >> I have not seen a specific lab author since J602. Do you know of one or are >> we following the "use any text editor" advice? >> >> http://www.jsoftware.com/jwiki/Labs >> >> Cheers, bob >> >> On Apr 23, 2014, at 11:23 AM, Raul Miller <rauldmil...@gmail.com> wrote: >> >> > If you are interested, you might consider putting together a J lab on the >> > subject. >> > >> > This would: >> > >> > (a) Help you retain the concepts for yourself, and expand your >> > understanding of them, and >> > (b) Help convey them to other people, also. >> > >> > If this interests you, we can help point you at lab authoring >> > documentation. We need some people interested in writing some labs >> because >> > the new platforms (especially phones) have UI adaptations which need some >> > fixing, for labs. >> > >> > Meanwhile, one of the more important issues for an author is finding a >> good >> > reviewing audience to work with. (Even more important, of course, is >> > writing stuff.) >> > >> > Thanks, >> > >> > -- >> > Raul >> > >> > >> > On Wed, Apr 23, 2014 at 1:52 PM, alexgian <alexg...@blueyonder.co.uk> >> wrote: >> > >> >>> The information and more are in the vocabulary page for %. >> >> >> >> Well, yes, but so tersely and compactly expressed that you have to know >> the >> >> long answer before you understand it! I did look at the Vocab page, but >> >> didn't "get it", that's why I posted. >> >> >> >> It needed Roger's somewhat more expanded explanation for those of us >> that >> >> are somewhat slower on the uptake. That's why I said the Vocab could >> use a >> >> touch up. It is NOT user friendly, more of an ultra-coded reference. >> Of >> >> course, you might not see it this way, but I'd bet most newcomers would. >> >> >> >> And it's not as if there is a longer explanation somewhere else, is >> there? >> >> Well, other than this thread, I mean... :) >> >> >> >> >> >> >> >> On 23 April 2014 18:17, Roger Hui <rogerhui.can...@gmail.com> wrote: >> >> >> >>> The information and more are in the vocabulary page for %. >> >>> http://www.jsoftware.com/help/dictionary/d131.htm . >> >>> >> >>> >> >>> On Wed, Apr 23, 2014 at 10:02 AM, alexgian <alexg...@blueyonder.co.uk >> >>>> wrote: >> >>> >> >>>> Great info, thanks Roger. >> >>>> If it was up to me, I'd DEFINITELY include that in the Vocabulary, is >> >> it >> >>>> even documented anywhere else? >> >>>> >> >>>> >> >>>> On 23 April 2014 17:33, Roger Hui <rogerhui.can...@gmail.com> wrote: >> >>>> >> >>>>> %. x for a vector x is the same as ($x)$%.,.x, and the key expression >> >>> is >> >>>>> %.,.x, the "matrix inverse" of a 1-column matrix. b=.y%.x on a tall >> >>>> matrix >> >>>>> x is solving a least-squares problem, the coefficients b that >> >> minimizes >> >>>> the >> >>>>> sum of squares of y - x +/ .* b . >> >>>>> >> >>>>> In addition, for a non-zero vector x, (%.x) +/ .* x is 1, a special >> >>> case >> >>>> of >> >>>>> that (%.x)+/ .* x is an identity matrix, whence one can deduce that >> >> for >> >>>>> vector x, %.x is x%+/x^2. >> >>>>> >> >>>>> ] x=: 7 ?.@$ 100 >> >>>>> 94 56 8 6 85 48 66 >> >>>>> %. x >> >>>>> 0.00362137 0.00215741 0.000308202 0.000231152 0.00327465 0.00184921 >> >>>>> 0.00254267 >> >>>>> (%.x) +/ .* x >> >>>>> 1 >> >>>>> x % +/x^2 >> >>>>> 0.00362137 0.00215741 0.000308202 0.000231152 0.00327465 0.00184921 >> >>>>> 0.00254267 >> >>>>> >> >>>>> M=: 7 3 ?.@$ 100 >> >>>>> (%.M) +/ .* M >> >>>>> 1 5.55112e_17 _2.77556e_17 >> >>>>> _1.21431e_16 1 1.11022e_16 >> >>>>> _4.85723e_17 1.94289e_16 1 >> >>>>> >> >>>>> >> >>>>> >> >>>>> On Wed, Apr 23, 2014 at 9:13 AM, alexgian <alexg...@blueyonder.co.uk >> >>> >> >>>>> wrote: >> >>>>> >> >>>>>> Just wondering: >> >>>>>> %. 2 3 4 >> >>>>>> 0.0689655 0.103448 0.137931 >> >>>>>> >> >>>>>> Which is fair enough enough at one level, I suppose, since the dot >> >>>>> product >> >>>>>> of the two arrays IS 1, but what system/equation is being solved >> >>> here? >> >>>>>> Obviously, there are infinite solutions. Why that one? >> >>>>>> IOW, which "matrix" is being inverted here? >> >>>>>> >> >>>>>> 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 >> >>> >> >> ---------------------------------------------------------------------- >> >> 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
