or (,&'x')\.&.": 357686312646216567629137x or for vertical display ,.(,&'x')\.&.": 357686312646216567629137x
On Sat, Nov 19, 2022 at 5:04 PM Elijah Stone <elro...@elronnd.net> wrote: > > x: ". y where y is simply a string of digits will interpret those digits as a > (fixed-width) integer and _then_ convert the latter to extended-precision. > You could append an 'x', or perhaps consider the following definition: > > truncs=. [:~. [:10&#.\. 10&#.^:_1 NB.equivalent to ltrunc^:a: > ,.truncs 357686312646216567629137x > 357686312646216567629137 > 57686312646216567629137 > 7686312646216567629137 > 686312646216567629137 > 86312646216567629137 > 6312646216567629137 > 312646216567629137 > 12646216567629137 > 2646216567629137 > 646216567629137 > 46216567629137 > 6216567629137 > 216567629137 > 16567629137 > 6567629137 > 567629137 > 67629137 > 7629137 > 629137 > 29137 > 9137 > 137 > 37 > 7 > > On Sat, 19 Nov 2022, Richard Donovan wrote: > > > Hi > > > > I am doing experiments with large primes, in particular looking at primes > > that remain primes when n digits are truncated from the left. For example > > 6391373 391373 91373 1373 373 73 3 remains prime at each > > step. > > > > The largest of these in base 10 is 357686312646216567629137. > > > > I wrote the following code in preparation for further investigation but I > > find that the 24 digit number above is not handled as I wish it to be, as > > you will see below. > > > > What have I missed? > > > > Thanks > > > > > > > > > > digits > > "."0@": > > > > ltrunc > > 3 : 0"0 0 0 > > n=: ": 0, }. digits y > > x: ". n-. ' ' > > ) > > > > > > > > NB. Works fine with 7 digit number... > > ltrunc^:a: 6391373 > > 6391373 391373 91373 1373 373 73 3 0 > > > > > > NB. But I can’t get it working for a 24 digit number! > > ltrunc 357686312646216567629137 > > 0 0 5 7 6 8 6 0 2 3 > > ltrunc 357686312646216567629137x > > 57686312646216568012800 > > ltrunc x:357686312646216567629137x > > 57686312646216568012800 > > > > Is there a way around the limit? > > > > ---------------------------------------------------------------------- > > 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
