Re: [Chicken-users] Speeding up bit-vector operation (using iset)

[felix winkelmann]

On Wed, Mar 17, 2010 at 1:18 PM, Alex Shinn <address@hidden> wrote:
>
> At 2^26 bits each I would say these are *huge* bit-vectors.
>
>> (do
>>   ((i 0 (+ 1 i)))
>>   ((= i 10))
>>   (bit-vector-and s1 s2)
>>   (bit-vector-ior s1 s2)
>>   (bit-vector-and s1 (bit-vector-nand s2)))
>
> These operations are generating three new huge bit-vectors
> on each iteration, so you're spending all your time in GC
> (and the loop has no effect).

I don't think this is completely true. GC-time is quite considerable,
but the loops
in iset.c are not tight enough for so many iterations (which is mostly
caused by slow XXXvector operations that require a full CPS call).

Using bignums (the new "standalone" version, which unfortunately has a bug
in `random') or crunch would be an interesting exercise.


cheers,
felix