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.
>>>
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