• yawniek (6/6) Mar 01 2016 i figured i can count the number of bits set for a BitArray with
• Andrea Fontana (2/8) Mar 01 2016 Maybe you should look for "hamming weight" :)
• yawniek (6/7) Mar 01 2016 maybe. and here is a snowman for you: ☃

yawniek <dlang srtnwz.com> writes:

i figured i can count the number of bits set for a BitArray with 
std.algorithm : count:

BitArray([0,0,1]).bitsSet.count()

but this seems not very optimal, is there a faster way directly 
accessible trough phobos?

ideally something that is optimized by the compiler.

Andrea Fontana <nospam example.com> writes:

On Tuesday, 1 March 2016 at 09:03:47 UTC, yawniek wrote:
 i figured i can count the number of bits set for a BitArray 
 with std.algorithm : count:

 BitArray([0,0,1]).bitsSet.count()

 but this seems not very optimal, is there a faster way directly 
 accessible trough phobos?

 ideally something that is optimized by the compiler.

Maybe you should look for "hamming weight" :)

yawniek <dlang srtnwz.com> writes:

On Tuesday, 1 March 2016 at 09:32:20 UTC, Andrea Fontana wrote:
 Maybe you should look for "hamming weight" :)

maybe. and here is a snowman for you: ☃

the question was if it exists for BitArray in phobos.

https://issues.dlang.org/show_bug.cgi?id=10239 so apparently its 
really missing in phobos BitArray. the algo is even described in 
TDPL.