See https://code.jsoftware.com/wiki/Essays/Factorings
On Fri, Apr 24, 2020 at 11:29 AM Skip Cave <[email protected]> wrote: > I want to find all the integer factors of a positive integer, > which includes 1 and the integer. > Here's a brute force verb I wrote: > fac=:3 : 'a#~0=(a=.1+i.y)|y' > > Test it: > > fac each 40+i.5 > > │1 2 4 5 8 10 20 40│1 41│1 2 3 6 7 14 21 42│1 43│1 2 4 11 22 44│ > > > However my fac verb is inefficient, slow, and runs out of memory quickly on > larger integers. Is there a way to take advantage of J's prime factoring > verb q: to more efficiently find and/or count *all* positive factors (not > just primes) of a large (>1e7) integers? > > > Skip > > > Skip Cave > Cave Consulting LLC > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
