Enhancement Request: Adding population count for Integers to
the standard image
Richard A. O'Keefe
ok at cs.otago.ac.nz
Sun Dec 12 22:36:28 UTC 2004
Am 10.12.2004 um 13:54 schrieb stéphane ducasse:
> why don't you call your method numberOfZeros? because it is talking
> better to me.
The reason is simple.
The operation f : natural numbers -> natural numbers
f x = number of 1s in binary representation of x
is traditionally known as "population count".
POWER 5 instruction set:
popcntbd RS, RA "Population Count Byte Doubleword"
Control Data machines
The instruction was known as "population count" but I've never
seen a COMPASS manual so don't know the mnemonic.
ctpop Rb.rq,Rc.wq "Count population; assembler"
x = _POPCNT(y) "Population count; C"
popc src,dst "Population Count"
So the chances are that anyone who wants the operation will know it by
the name "population count" and will look for
If you think of a non-negative integer as representing a set, then the
name almost makes sense.
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