Thanks for fixing it. (The no workaround bit is disappointing, given how many J versions this hits. But maybe I can do something for the pritchard sieve...)
Thanks again, -- Raul On Sun, Aug 28, 2022 at 10:10 AM Henry Rich <[email protected]> wrote: > > Fixed for the next beta. The error occurred on (sparse list i. dense) > when the sparse list had length > 0 but no non-sparse elements. No > workaround. > > The bug was very old. > > Henry Rich > > On 8/27/2022 4:00 AM, 'Mike Day' via Beta wrote: > > “probably, earlier versions of J). “ : > > > > FWIW, on this iPad, running J701, so changing {{}} to 3 : 0 .... ), > > (and pritchard to pritch!), I get the same results. > > > > Mike > > > > Sent from my iPad > > > >> On 27 Aug 2022, at 02:51, Raul Miller <[email protected]> wrote: > >> > >> I'm seeing strange behavior with sparse arrays, and I have been mostly > >> unsuccessful in simplifying code exhibiting the problem. Thus: > >> > >> pritch=: {{ > >> spokes=. $.,1 > >> primes=. i.0 > >> while. y > #spokes do. > >> primes=. primes, p=. 2+(}.spokes) i.1 NB. find next prime > >> rim=. #spokes NB. "length" of "circumference" of wheel > >> spokes=. (y<.p*rim)$spokes NB. roll next larger wheel > >> spokes=. 0 ((#~ y>])_1+p*1+i.rim)} spokes > >> end. > >> NB. elided code here > >> primes,1+}.,I.spokes > >> }} > >> > >> pritchard 20 > >> 2 3 5 7 11 13 17 19 > >> > >> pritch8=: {{ > >> spokes=. $.,1 > >> primes=. i.0 > >> while. y > #spokes do. > >> primes=. primes, p=. 2+(}.spokes) i.1 NB. find next prime > >> rim=. #spokes NB. "length" of "circumference" of wheel > >> spokes=. (y<.p*rim)$spokes NB. roll next larger wheel > >> spokes=. 8 $. 0 ((#~ y>])_1+p*1+i.rim)} spokes > >> end. NB. elided code here > >> primes,1+}.,I.spokes > >> }} > >> pritch8 20 > >> 2 2 3 5 7 11 13 17 19 > >> > >> Somehow the value for p is different when 8 $. is present in this > >> particular implementation (though I don't observe similar behavior in > >> similar uses of 8 $. y). > >> > >> I'm reporting this on the beta forum, but it's an issue in J903 (and, > >> probably, earlier versions of J). > >> > >> FYI, > >> > >> -- > >> Raul > >> ---------------------------------------------------------------------- > >> 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
