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
