Hmm, [ some XXX module ] might speed it up ?

At the very minimum, the code would need to increment an integer (one of many) , 500 * 50000 times. That takes at least 1.6 seconds in Perl:

$t=time; 
$i=0; 
++$i for 1 .. 25e6; 
print time-$t;;
1.66395616531372

[download]

That 7000 times too slow for the OPs target rate.

And that's before you take into account indexing into the arrays; indexing into the counts; and scanning the final tallies to determine which count is highest.

This is impossible using a single machine, even if written in highly optimised C or assembler.

It might just be possible if you can throw enough hardware at the problem such that you could pre-index every possible combination. Maybe.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
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.

In reply to Re^5: Fast algorithm for 2d array queries (Got OpenGL::Array) by BrowserUk
in thread Fast algorithm for 2d array queries by baxy77bax

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