Since the consensus seems to be that this is acceptable, I will say no more.
Thanks for taking the time to reply. Regards, Rob. > On 7 Sep 2017, at 19:05, Raul Miller <rauldmil...@gmail.com> wrote: > > Where would a new user get those large numbers? > > That said, new users should be expected to either (a) read the > documentation, or (b) be puzzled at times and perhaps have to talk > with people. > > In this case, http://www.jsoftware.com/help/dictionary/dcons.htm might > be relevant. > > Thanks, > > -- > Raul > >> On Thu, Sep 7, 2017 at 9:41 AM, Rob B <rb75...@me.com> wrote: >> How would a new user know that using mod with large numbers was 'asking the >> wrong question'? >> >> Surely user-friendly code protects the user as its first priority? >> >> Regards, Rob. >> >>> On 7 Sep 2017, at 14:24, Eric Iverson <eric.b.iver...@gmail.com> wrote: >>> >>> Rob, >>> >>> To get your right answer, you have to ask the right question. It seems in >>> your case the right question has x: and for others the right question does >>> not. >>> >>>> On Thu, Sep 7, 2017 at 9:17 AM, Rob B <rb75...@me.com> wrote: >>>> >>>> I would sooner get the right answer slowly than the wrong answer quickly. >>>> >>>> Regards, Rob. >>>> >>>>> On 7 Sep 2017, at 13:48, Raul Miller <rauldmil...@gmail.com> wrote: >>>>> >>>>> Those proposals would cause operations on large arrays to >>>>> intermittently stall or spam. >>>>> >>>>> FYI, >>>>> >>>>> -- >>>>> Raul >>>>> >>>>> >>>>>> On Thu, Sep 7, 2017 at 7:54 AM, Rob B <rb75...@me.com> wrote: >>>>>> Thanks Raul, I am familiar with these ideas, and using x: is almost a >>>> reflex now. >>>>>> >>>>>> I feel that to protect the new J user, mod should convert to extended >>>> precision automatically or issue an warning message. Giving tha answer zero >>>> is very misleading. >>>>>> >>>>>> PS I am not so concerned with small numbers and measurability as with >>>> large numbers and primality. Heisenberg's Uncertainty Principle is not >>>> usually an issue for me :) >>>>>> >>>>>> Ragards, Rob. >>>>>> >>>>>>> On 7 Sep 2017, at 11:32, Raul Miller <rauldmil...@gmail.com> wrote: >>>>>>> >>>>>>> The answer, oddly enough, is: yes. >>>>>>> >>>>>>> The philosophical arguments are buried here: >>>>>>> >>>>>>> https://en.wikipedia.org/wiki/Accuracy_and_precision >>>>>>> >>>>>>> The technical issues are buried here: >>>>>>> >>>>>>> https://en.wikipedia.org/wiki/IEEE_754 >>>>>>> >>>>>>> That said, if you have reason to be using numbers which are precise >>>>>>> beyond anyone's ability to measure (and keep in mind Heisenberg >>>>>>> Uncertainty as one of the practical limits on measurability), you >>>>>>> should probably be using extended precision numbers (123x instead of >>>>>>> 123). This will give you exact results in exchange for a performance >>>>>>> penalty. >>>>>>> >>>>>>> Thanks, >>>>>>> >>>>>>> -- >>>>>>> Raul >>>>>>> >>>>>>> >>>>>>>> On Thu, Sep 7, 2017 at 4:42 AM, Rob B <rb75...@me.com> wrote: >>>>>>>> On reflection my real question is; should mod suddenly and without >>>> warning give the wrong answer when a number gets suffiently large? I have >>>> been caught by this many times. The incorrect answer zero is problematic as >>>> it suggests divisibility. >>>>>>>> >>>>>>>> Apologies if this has all been discussed before. >>>>>>>> >>>>>>>> Regards, Rob Burns. >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>>> On 6 Sep 2017, at 09:11, Rob B <rb75...@icloud.com> wrote: >>>>>>>>> >>>>>>>>> Thanks, >>>>>>>>> >>>>>>>>> I now see it's reasonable for ^ to convert to flost and *: to remain >>>> exact. >>>>>>>>> >>>>>>>>> The other discrepancy is probably due to my old version, iPad 701. >>>>>>>>> >>>>>>>>> Regards, Rob Burns. >>>>>>>>> >>>>>>>>>> On 5 Sep 2017, at 17:48, HenryRich <henryhr...@gmail.com> wrote: >>>>>>>>>> >>>>>>>>>> datatype 47^2 >>>>>>>>>> >>>>>>>>>> floating >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> So >>>>>>>>>> >>>>>>>>>> (n^2) | 5729082486784839 >>>>>>>>>> >>>>>>>>>> is promoted to float, and loses precision. Same when the big >>>> number is extended - it's converted to float. >>>>>>>>>> >>>>>>>>>> For >>>>>>>>>> >>>>>>>>>> (x: n^2) | 5729082486784839 >>>>>>>>>> >>>>>>>>>> I get 147 as the result. >>>>>>>>>> >>>>>>>>>> Henry Rich >>>>>>>>>> >>>>>>>>>>> On 9/5/2017 12:41 PM, Rob B wrote: >>>>>>>>>>> Could someone explain this please? >>>>>>>>>>> >>>>>>>>>>> n=.14 >>>>>>>>>>> n >>>>>>>>>>> 14 >>>>>>>>>>> (*: n) | 5729082486784839 >>>>>>>>>>> 147 >>>>>>>>>>> 196 | 5729082486784839 >>>>>>>>>>> 147 >>>>>>>>>>> (n^2) | 5729082486784839 >>>>>>>>>>> 0 >>>>>>>>>>> (n^2) | 5729082486784839x >>>>>>>>>>> 0 >>>>>>>>>>> (x: n^2) | 5729082486784839 >>>>>>>>>>> 0 >>>>>>>>>>> (x: n^2) | 5729082486784839x >>>>>>>>>>> 147 >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Regards, Rob Burns >>>>>>>>>>> ------------------------------------------------------------ >>>> ---------- >>>>>>>>>>> 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 > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
