Optimize Enumerable#sum for integer ranges #2359
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seven1m
approved these changes
Nov 25, 2024
We can simply shortcut this with the Guass formula for summing integers. It turns out MRI does this too Benchmarking this with `(1..1000000).sum`, this takes roughly 1.5 seconds on master (on my machine, release build), and only 0.00003 seconds with this patch. MRI is still roughly 10 times as fast. Inspired by https://mastodon.social/@riffraff/113503953295615142, mentioned on https://newsletter.shortruby.com/p/edition-115 MRI does not have a separate `Range#sum` method, so it looks like it is shortcutted in `Enumerable#range`.
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We can simply shortcut this with the Guass formula for summing integers. It turns out MRI does this too
Benchmarking this with
(1..1000000).sum, this takes roughly 1.5 seconds on master (on my machine, release build), and only 0.00003 seconds with this patch. MRI is still roughly 10 times as fast.Inspired by https://mastodon.social/@riffraff/113503953295615142, mentioned on https://newsletter.shortruby.com/p/edition-115
MRI does not have a separate
Range#summethod, so it looks like it is shortcutted inEnumerable#range.