Hi Bogdan, This is a brilliant solution and also completely over my head. It finishes in ~3.75s on my PC and is faster than the Python version which basically delegates all the work to C. I will need to spend some time on understanding it but I am looking forward to learning something new.
Many thanks, Pawel On Thursday, March 18, 2021 at 7:22:10 PM UTC bogdan wrote: > I managed to get it about as fast as Python by making it really > imperative and rolling my own hash: > > https://gist.github.com/Bogdanp/fb39d202037cdaadd55dae3d45737571 > > Sam Tobin-Hochstadt writes: > > > Here are several variants of the code: > > https://gist.github.com/d6fbe3757c462d5b4d1d9393b72f9ab9 > > > > The enabled version is about the fastest I can get without using > > `unsafe` (which the rules said not to do). It's possible to optimize a > > tiny bit more by avoiding sorting, but only a few milliseconds -- it > > would be more significant if there were more different words. > > > > Switching to bytes works correctly for the given task, but wouldn't > > always work in the case of general UTF8 input. But those versions > > appeared not be faster for me. Also, writing my own string-downcase > > didn't help. And using a big buffer and doing my own newline splitting > > didn't help either. > > > > The version using just a regexp matching on a port (suggested by > > Robby) turned out not to be faster either, so my suspicion is that the > > original slowness is just using regexps for splitting words. > > > > Sam > > > > On Thu, Mar 18, 2021 at 11:28 AM Sam Tobin-Hochstadt > > <[email protected]> wrote: > >> > >> Here's a somewhat-optimized version of the code: > >> > >> #lang racket/base > >> (require racket/string racket/vector racket/port) > >> > >> (define h (make-hash)) > >> > >> (time > >> (for* ([l (in-lines)] > >> [w (in-list (string-split l))] > >> [w* (in-value (string-downcase w))]) > >> (hash-update! h w* add1 0))) > >> > >> (define v > >> (time > >> (for/vector #:length (hash-count h) > >> ([(k v) (in-hash h)]) > >> (cons k v)))) > >> (time (vector-sort! v > #:key cdr)) > >> (define p (current-output-port) #;(open-output-nowhere)) > >> (time > >> (for ([pair (in-vector v)]) > >> (write-string (car pair) p) > >> (write-string (number->string (cdr pair)) p) > >> (newline p))) > >> > >> It's much more imperative, but also pretty nice and compact. The > >> `printf` optimization is significant for that portion of the program, > >> but that isn't much of the running time. The overall running time for > >> 10 copies of the KJV is about 9 seconds on my laptop. > >> > >> I think the remaining difference between Racket and other languages is > >> likely the `string-split` and `string-downcase` functions, plus the > >> relatively-inefficient string representation that Racket uses. > >> > >> Sam > >> > >> > >> On Thu, Mar 18, 2021 at 10:28 AM Pawel Mosakowski <[email protected]> > wrote: > >> > > >> > Hi David, > >> > > >> > Yes, the 21 seconds includes the interpreter startup time. I have > done a simple test to see how long it takes: > >> > > >> > $ time racket -e '(displayln "Hello, world")' > >> > Hello, world > >> > > >> > real 0m0.479s > >> > user 0m0.449s > >> > sys 0m0.030s > >> > > >> > I have also put my code inside a main function and profiled it: > >> > > >> > Profiling results > >> > ----------------- > >> > Total cpu time observed: 20910ms (out of 20970ms) > >> > Number of samples taken: 382 (once every 55ms) > >> > (Hiding functions with self<1.0% and local<2.0%: 1 of 12 hidden) > >> > > >> > ============================================================== > >> > Caller > >> > Idx Total Self Name+src Local% > >> > ms(pct) ms(pct) Callee > >> > ============================================================== > >> > [1] 20910(100.0%) 0(0.0%) [running body] > ...word-occurences-profile.rkt":##f > >> > profile-thunk [2] 100.0% > >> > -------------------------------------------------------------- > >> > [running body] [1] 100.0% > >> > [2] 20910(100.0%) 0(0.0%) profile-thunk > ...ket/pkgs/profile-lib/main.rkt:9:0 > >> > run [3] 100.0% > >> > -------------------------------------------------------------- > >> > profile-thunk [2] 100.0% > >> > [3] 20910(100.0%) 0(0.0%) run > ...share/racket/pkgs/profile-lib/main.rkt:39:2 > >> > main [4] 100.0% > >> > -------------------------------------------------------------- > >> > run [3] 100.0% > >> > [4] 20910(100.0%) 50(0.2%) main > ...cket/count-word-occurences-profile.rkt:5:0 > >> > read-from-stdin-it [5] 98.5% > >> > ??? [6] 0.2% > >> > -------------------------------------------------------------- > >> > main [4] 100.0% > >> > [5] 20606(98.5%) 11796(56.4%) read-from-stdin-it > ...-occurences-profile.rkt:19:6 > >> > internal-split [7] 42.8% > >> > -------------------------------------------------------------- > >> > main [4] 100.0% > >> > [6] 51(0.2%) 0(0.0%) ??? > ...cket/collects/racket/private/sort.rkt:369:3 > >> > generic-sort/key [8] 100.0% > >> > -------------------------------------------------------------- > >> > read-from-stdin-it [5]100.0% > >> > [7] 8810(42.1%) 3528(16.9%) internal-split > ...collects/racket/string.rkt:117:0 > >> > regexp-split [9] 59.9% > >> > -------------------------------------------------------------- > >> > ??? [6] 100.0% > >> > [8] 51(0.2%) 0(0.0%) generic-sort/key > .../racket/private/sort.rkt:156:2 > >> > copying-mergesort [10]100.0% > >> > -------------------------------------------------------------- > >> > internal-split [7] 100.0% > >> > [9] 5282(25.3%) 2810(13.4%) regexp-split > ...ts/racket/private/string.rkt:338:2 > >> > loop [11] 46.8% > >> > -------------------------------------------------------------- > >> > generic-sort/key [8] 10.0% > >> > copying-mergesort [10] 90.0% > >> > [10] 51(0.2%) 51(0.2%) copying-mergesort > ...racket/private/sort.rkt:129:8 > >> > copying-mergesort [10] 90.0% > >> > -------------------------------------------------------------- > >> > regexp-split [9] 100.0% > >> > [11] 2471(11.8%) 2471(11.8%) loop > ...t/collects/racket/private/string.rkt:169:7 > >> > -------------------------------------------------------------- > >> > > >> > Kind regards, > >> > Pawel > >> > > >> > > >> > On Thursday, March 18, 2021 at 2:09:35 PM UTC [email protected] > wrote: > >> >> > >> >> Hi Pawel, > >> >> > >> >> I'll take a look at the code later, but did that 21 seconds include > startup time for the interpreter? > >> >> > >> >> On Thu, Mar 18, 2021, 9:24 AM Pawel Mosakowski <[email protected]> > wrote: > >> >>> > >> >>> Hello, > >> >>> > >> >>> I am a Racket beginner and I have come across this article: > >> >>> > >> >>> https://benhoyt.com/writings/count-words/ > >> >>> > >> >>> This is my attempt at solving the challenge: > >> >>> > >> >>> https://pastebin.com/kL16w5Hc > >> >>> > >> >>> However when I have benchmarked it, it takes ~21 seconds to run > compared to the Python and Ruby versions which take around 3-4 seconds. > >> >>> > >> >>> I understand that both Ruby and Python probably have the string > operations and hash tables implemented in optimized C but is there anything > I can do to improve performance of my program? > >> >>> > >> >>> Many thanks for all help and suggestions. > >> >>> > >> >>> -- > >> >>> You received this message because you are subscribed to the Google > Groups "Racket Users" group. > >> >>> To unsubscribe from this group and stop receiving emails from it, > send an email to [email protected]. > >> >>> To view this discussion on the web visit > https://groups.google.com/d/msgid/racket-users/118c1340-66d1-421d-92a4-6b66c56cb88fn%40googlegroups.com > . > >> > > >> > -- > >> > You received this message because you are subscribed to the Google > Groups "Racket Users" group. > >> > To unsubscribe from this group and stop receiving emails from it, > send an email to [email protected]. > >> > To view this discussion on the web visit > https://groups.google.com/d/msgid/racket-users/09c58a34-bd2d-49e7-bfbd-d3253c1e6dd1n%40googlegroups.com > . > -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/ca365c42-d698-4e43-863e-7fc95849c31en%40googlegroups.com.
