I realized y, actually its real backer, of argument to the explicit definition can be changed or deleted by users code inside the explicit verb. The worst case is just the need to value copy y before its mutation, the penalty is the same as that now.
On Sun, May 17, 2020, 9:39 PM Henry Rich <[email protected]> wrote: > You make a good point, which never occurred to me. But in 'a b c =. y', > the values are usually boxed & a virtual value would not be generated > anyway. > > What you may be remembering is that results of explicit definitions can > now be inplaceable, which is not the same as virtual. > > I had convinced myself that assigning/boxing virtual blocks was > impossible for reasons other than space, but I am no longer sure about > that. I can't find anything in the commentary to explain why, and > that's the sort of thing I would usually write down. So I will try it, > allowing an assignment to remain virtual if it has 90% of the atoms of > the backer. Watch this space. > > Henry Rich > > On 5/16/2020 9:25 PM, bill lam wrote: > > in the context of explicit definition. y is always there, so it should be > > harmless. I thought you had already done that. My memory no longer serve > me? > > > > On Sun, May 17, 2020, 9:16 AM Henry Rich <[email protected]> wrote: > > > >> No, because if y, a, and b are deleted, you are left holding y when all > >> you need is c. > >> > >> Henry Rich > >> > >> On 5/16/2020 8:52 PM, bill lam wrote: > >>> but then the indirect assignment > >>> 'a b c'=. y > >>> should use up entire y, just increasing usecount shouldn't be a > problem. > >> I > >>> think this is already implemented, am I right? > >>> > >>> On Sun, May 17, 2020, 8:13 AM Henry Rich <[email protected]> wrote: > >>> > >>>> c =. 1 { a is problematic because if a is deleted, you are left > holding > >>>> the entire a just to make one item available. That would waste space. > >>>> > >>>> b =. , a could perhaps increase the usecount of the backer, but I > didn't > >>>> implement it that way, and I think I decided it wouldn't work to, but > I > >>>> can't remember why. Once you know about virtual blocks you might stop > >>>> writing b =. , a and use (,a) instead. > >>>> > >>>> Henry Rich > >>>> > >>>> On 5/16/2020 6:43 PM, bill lam wrote: > >>>>> Shouldn't assignment like > >>>>> b=. , a > >>>>> c=. 1{a > >>>>> just increase reference count of the mother instead of deep copy? > >>>>> > >>>>> > >>>>> On Sun, May 17, 2020, 6:27 AM Henry Rich <[email protected]> > wrote: > >>>>> > >>>>>> I wouldn't say so. Reshape takes virtually no time/space, but > boxing > >> or > >>>>>> assigning the reshaped result does. If you do something like > >>>>>> > >>>>>> +/ @: (,/) y > >>>>>> > >>>>>> the result of ,/ is never realized and it would be wrong to charge > it > >>>>>> with time/space not used. > >>>>>> > >>>>>> Similarly > >>>>>> > >>>>>> (}. - }:) y > >>>>>> > >>>>>> the }. and }: create virtual results that are never realized. > >>>>>> > >>>>>> You need to expand your mental model beyond time/space for a verb, > to > >>>>>> include time/space for realization when that becomes necessary. > >>>>>> > >>>>>> Henry Rich > >>>>>> > >>>>>> > >>>>>> On 5/16/2020 1:22 PM, 'Mike Day' via Programming wrote: > >>>>>>> Oh... so one needs to, say, assign the result to see the real t/s? > >>>>>>> > >>>>>>> Thanks, > >>>>>>> > >>>>>>> Mike > >>>>>>> > >>>>>>> Sent from my iPad > >>>>>>> > >>>>>>>> On 16 May 2020, at 17:05, Henry Rich <[email protected]> > wrote: > >>>>>>>> > >>>>>>>> The time/space numbers are telling you that (x $ y) produces a > >> virtual > >>>>>> result when it can, while (_2 ]\ y) doesn't (yet). If you use the > >>>> result > >>>>>> immediately, the space saving is real. If you box the result or > save > >>>> it in > >>>>>> a name, the value will be realized and the space saving will vanish. > >>>>>>>> Henry Rich > >>>>>>>> > >>>>>>>>> On 5/16/2020 11:14 AM, 'Michael Day' via Programming wrote: > >>>>>>>>> Much neater than what I was about to offer, unless Raoul needs > to > >>>>>> specify the fill, > >>>>>>>>> in which case, this alternative rather minimal amendment is > worth > >>>>>> consideration: > >>>>>>>>> ($!._ ~2,~>.@-:@#) i.7 > >>>>>>>>> 0 1 > >>>>>>>>> 2 3 > >>>>>>>>> 4 5 > >>>>>>>>> 6 _ > >>>>>>>>> > >>>>>>>>> cf > >>>>>>>>> > >>>>>>>>> _2]\ i.7 > >>>>>>>>> 0 1 > >>>>>>>>> 2 3 > >>>>>>>>> 4 5 > >>>>>>>>> 6 0 > >>>>>>>>> > >>>>>>>>> Also, the time and space performance _might_ be important for > large > >>>>>> inputs: > >>>>>>>>> ts' $ _2]\ list ' [list =: i.100000 > >>>>>>>>> 0.000618 1.04986e6 > >>>>>>>>> ts'($!._ ~2,~>.@-:@#) list' > >>>>>>>>> 2.7e_6 2304 > >>>>>>>>> > >>>>>>>>> Cheers, > >>>>>>>>> > >>>>>>>>> Mike > >>>>>>>>> > >>>>>>>>>> On 16/05/2020 15:57, 'Rob Hodgkinson' via Programming wrote: > >>>>>>>>>> You could try Infix … here with NuVoc link… > >>>>>>>>>> https://code.jsoftware.com/wiki/Vocabulary/bslash#dyadic > >>>>>>>>>> > >>>>>>>>>> x u\ y where x is eg _2 means apply very b to successive > >> pairs > >>>>>> (_ for non-overlapping). > >>>>>>>>>> _2 ]\ 1 2 3 4 5 6 > >>>>>>>>>> 1 2 > >>>>>>>>>> 3 4 > >>>>>>>>>> 5 6 > >>>>>>>>>> _2 ]\ 1 2 3 4 5 6 7 > >>>>>>>>>> 1 2 > >>>>>>>>>> 3 4 > >>>>>>>>>> 5 6 > >>>>>>>>>> 7 0 > >>>>>>>>>> > >>>>>>>>>> _2 <\ 1 2 3 4 5 6 > >>>>>>>>>> ┌───┬───┬───┐ > >>>>>>>>>> │1 2│3 4│5 6│ > >>>>>>>>>> └───┴───┴───┘ > >>>>>>>>>> > >>>>>>>>>> HTH…/Rob > >>>>>>>>>> > >>>>>>>>>>> On 17 May 2020, at 12:42 am, Raoul Schorer < > >>>> [email protected]> > >>>>>> wrote: > >>>>>>>>>>> Hello, > >>>>>>>>>>> > >>>>>>>>>>> I am convinced that this must be trivial, but I wasn't able to > >> find > >>>>>> in the documentation how to reshape a list to a table without > manually > >>>>>> extracting the length. > >>>>>>>>>>> in summary, is there a more direct way of doing: > >>>>>>>>>>> > >>>>>>>>>>> lst =. i. 6 > >>>>>>>>>>> > >>>>>>>>>>> ((2,~2%~#) $ ]) lst > >>>>>>>>>>> > >>>>>>>>>>> for a list of arbitrary length? > >>>>>>>>>>> > >>>>>>>>>>> Thanks! > >>>>>>>>>>> > >>>>>>>>>>> Raoul > >>>>>>>>>>> > >>>>>>>>>>> > >>>>>> > ---------------------------------------------------------------------- > >>>>>>>>>>> For information about J forums see > >>>>>> http://www.jsoftware.com/forums.htm > >>>> ---------------------------------------------------------------------- > >>>>>>>>>> For information about J forums see > >>>>>> http://www.jsoftware.com/forums.htm > >>>>>>>> -- > >>>>>>>> This email has been checked for viruses by AVG. > >>>>>>>> https://www.avg.com > >>>>>>>> > >>>>>>>> > >> ---------------------------------------------------------------------- > >>>>>>>> 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 > >>>> -- > >>>> This email has been checked for viruses by AVG. > >>>> https://www.avg.com > >>>> > >>>> ---------------------------------------------------------------------- > >>>> For information about J forums see > http://www.jsoftware.com/forums.htm > >>>> > >>> ---------------------------------------------------------------------- > >>> For information about J forums see http://www.jsoftware.com/forums.htm > >> > >> -- > >> This email has been checked for viruses by AVG. > >> https://www.avg.com > >> > >> ---------------------------------------------------------------------- > >> For information about J forums see http://www.jsoftware.com/forums.htm > >> > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > -- > This email has been checked for viruses by AVG. > https://www.avg.com > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
