On a side note: are you aware of multi-dim hashes in Perl?
No, I wasn't aware of them. Curiously, when I added them to my original test, they turned out to be slower than join. That is, Multi: 
exists $cells->{$p->[0],$p->[1]} or die;

[download]
was slower than Str: 
exists $cells->{ join ':', @{$p} } or die;

[download]
Benchmark results: 
Str:   7 wallclock secs ( 6.58 usr + 0.00 sys =.58 CPU) @ 30404.38/s (
+n=200000)
Multi: 8 wallclock secs ( 7.98 usr + 0.00 sys =.98 CPU) @ 25050.10/s (
+n=200000)

[download]

Update: though Multi was faster than: 

exists $cells->{ join ':', $p->[0], $p->[1] } or die;

[download]

In reply to Re^2: Fastest way to lookup a point in a set by eyepopslikeamosquito
in thread Fastest way to lookup a point in a set by eyepopslikeamosquito

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