For what it's worth, here's what I was focusing on: http://rosettacode.org/wiki/Cyclotomic_polynomial#J
As you can see, I altered your polynomial division algorithm -- there's enough zeros in the polynomials I was working with, there, that iterating through them seemed unwise. If there's any other significant improvements that you notice -- or any errors which I overlooked, of course, please let me know! Thanks, -- Raul On Sun, Feb 20, 2022 at 11:27 AM 'Michael Day' via Programming <programm...@jsoftware.com> wrote: > > I wrote binc as a monad, just as a quick way of conjuring up > sets of binomial coefficients: > > binc 5 > 1 5 10 10 5 1 > > 3 binc 5 NB. does work, but not as intended! > 1 3 3 1 0 0 > NB. as does its commute: > 5 binc 3 > 1 5 10 10 > ... but again, not as I intended. > > div is what does the division; div&binc a,b just > does (binc a) div binc b > > > I wasn't particularly interested in the performance of binc, > as Raul was seeking a division algortithm, and binc was > just easier than typing 1 5 10 10 5 1 or whatever. > > I do agree that your definition improves on mine when it > matters, eg > ts'binc 500x' > 0.0392271 460640 > ts'1, */\ 500x (- % >:@]) i.500x' NB. x=y for my examples > 0.001463 504032 > > I suppose it's now worth investigating the performance of > div cf dbho and divlo cf dblo excluding the overhead of binc: > > 'a b' =: binc 50 20 > a (dbho-:div) b > 1 > ts'a div b' > 1.21e_5 5952 > ts'a dbho b' > 2.63e_5 6496 > a (dblo-:divlo) b > 1 > ts'a divlo b' > 1.06e_5 6976 > ts'a dblo b' > 1.75e_5 6496 > > Thanks for pointing out the overheads imposed by binc, > > Mike > > On 20/02/2022 16:01, Hauke Rehr wrote: > > On my machine, I get > > > > 100 timespacex '1000x binc 500x' > > 0.101916 957376 > > 100 timespacex '1, */\ 1000x (- % >:@]) i.500x' > > 0.00247977 680320 > > > > > > Am 20.02.22 um 13:30 schrieb 'Michael Day' via Programming: > >> ts'1000x div&binc 500x' > >> 2.1598005 4815264 > > > > > -- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
