Index-Of: Inverted Tables
Index
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From
Rank & Friends
, Dyalog ’13.
inverted-table index-of
{(⍉↑⍺⍳¨⍺)⍳(⍉↑⍺⍳¨⍵)}
implemented in v14.0 as
8⌶
x ← x0 x1 x2 x3 y ← y0 y1 y2 y3 i ← x (8⌶) y
8⌶
exploits:
CRC32
instruction, SSE4.2,
circa
2008
“selfies”,
x(8⌶)x
other black arts ☺