Speed up CombinationHelper#4825
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ondrejmirtes merged 1 commit intophpstan:2.1.xfrom Jan 27, 2026
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This change swaps loops to reduce number of intermediate arrays allocated and flips direction in which results are constructed to eliminate explicit append loop. For 3 arrays with 10 elements each this leads to 5x speedup.
Contributor
how did you measure the speedup? |
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|
Thank you very much! |
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Author
PHP 8.4.16, JIT turned off, CPU i5-4570 and timed this loop $ass = array_fill(0,3, range(1,10));
$sink = 0;
for ($i = 0; $i < 20_000; $i++) {
$sink += count(iterator_to_array(CombinationsHelper::combinations($ass)));
}
var_dump($sink); |
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This change swaps loops to reduce number of intermediate arrays allocated and flips direction in which results are constructed to eliminate explicit append loop.
For 3 arrays with 10 elements each this leads to 5x speedup.