As long as we're (micro)optimizing, ...
I agree, that is a micro-optimisation :), but if you look at the bigger picture, your version is anything from 45% to 350% faster than the List::Util version--it's not so micro.
Plus, your solution inspired me to come up with this, I think, rather surprising version. It's not only faster again, sometimes as much as another 25% over the earlier gains, it's also arguably the most readable:
sub bukNew ($) {
my( $ref ) = @_;
my @x = 0 .. $#$ref;
@{ $ref }[ map splice( @x, rand @x, 1 ), @x ];
}
10 strings length 1.25892541179417
Rate naive listutil blokhead buk bukNew
naive 22172/s -- -41% -69% -69% -73%
listutil 37867/s 71% -- -47% -47% -54%
blokhead 71022/s 220% 88% -- -1% -14%
buk 72090/s 225% 90% 2% -- -12%
bukNew 82136/s 270% 117% 16% 14% --
10 strings length 10
Rate naive listutil blokhead buk bukNew
naive 20685/s -- -44% -70% -71% -75%
listutil 36824/s 78% -- -47% -49% -55%
blokhead 70065/s 239% 90% -- -3% -14%
buk 72090/s 249% 96% 3% -- -12%
bukNew 81717/s 295% 122% 17% 13% --
10 strings length 1000
Rate naive listutil blokhead buk bukNew
naive 1193/s -- -60% -98% -98% -99%
listutil 2981/s 150% -- -96% -96% -96%
blokhead 69931/s 5764% 2246% -- -2% -15%
buk 71723/s 5914% 2306% 3% -- -12%
bukNew 81873/s 6765% 2647% 17% 14% --
100 strings length 1.25892541179417
Rate naive listutil buk blokhead bukNew
naive 2190/s -- -45% -72% -73% -78%
listutil 3989/s 82% -- -49% -51% -60%
buk 7848/s 258% 97% -- -4% -21%
blokhead 8144/s 272% 104% 4% -- -18%
bukNew 9925/s 353% 149% 26% 22% --
100 strings length 10
Rate naive listutil buk blokhead bukNew
naive 2092/s -- -46% -73% -74% -79%
listutil 3868/s 85% -- -50% -52% -61%
buk 7811/s 273% 102% -- -4% -21%
blokhead 8094/s 287% 109% 4% -- -18%
bukNew 9873/s 372% 155% 26% 22% --
100 strings length 1000
Rate naive listutil buk blokhead bukNew
naive 96.3/s -- -58% -99% -99% -99%
listutil 229/s 138% -- -97% -97% -98%
buk 7811/s 8009% 3314% -- -4% -21%
blokhead 8094/s 8303% 3437% 4% -- -18%
bukNew 9869/s 10145% 4213% 26% 22% --
1000 strings length 1.25892541179417
Rate naive listutil buk blokhead bukNew
naive 208/s -- -41% -74% -75% -76%
listutil 350/s 69% -- -56% -58% -59%
buk 789/s 280% 125% -- -5% -7%
blokhead 827/s 298% 136% 5% -- -3%
bukNew 850/s 310% 143% 8% 3% --
1000 strings length 10
Rate naive listutil buk blokhead bukNew
naive 187/s -- -42% -76% -77% -78%
listutil 319/s 71% -- -59% -61% -62%
buk 777/s 316% 143% -- -5% -7%
blokhead 815/s 337% 155% 5% -- -2%
bukNew 834/s 347% 161% 7% 2% --
1000 strings length 1000
Rate naive listutil buk blokhead bukNew
naive 8.47/s -- -62% -99% -99% -99%
listutil 22.2/s 162% -- -97% -97% -97%
buk 785/s 9164% 3437% -- -3% -8%
blokhead 810/s 9470% 3554% 3% -- -5%
bukNew 850/s 9939% 3733% 8% 5% --
It's advantage tails off as the number of strings rise, but when you start seeing numbers like 20x, 30x and even 40x faster than the List::Util PP version, it seems possible that someone might benefit.
'sides, I think of optimising as a lot like obfu, a fun intellectual challange. Plus there is the upside that the results can be useful.
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
-
Are you posting in the right place? Check out Where do I post X? to know for sure.
-
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big>
<blockquote> <br /> <dd>
<dl> <dt> <em> <font>
<h1> <h2> <h3> <h4>
<h5> <h6> <hr /> <i>
<li> <nbsp> <ol> <p>
<small> <strike> <strong>
<sub> <sup> <table>
<td> <th> <tr> <tt>
<u> <ul>
-
Snippets of code should be wrapped in
<code> tags not
<pre> tags. In fact, <pre>
tags should generally be avoided. If they must
be used, extreme care should be
taken to ensure that their contents do not
have long lines (<70 chars), in order to prevent
horizontal scrolling (and possible janitor
intervention).
-
Want more info? How to link
or How to display code and escape characters
are good places to start.