Timon Gehr:
> http://pastebin.com/C6vf9DQQ
Very good.
> It delivers correct results, but it takes 20min to run. (probably mainly
> GC-related, I don't know)
DMD is not inlining those delegates, it is not merging streams as GHC does,
etc. But such missing optimizations aren't the main cause of that so low
performance. I think following those chains is a kind of worst-case for a
mark&sweep GC. If I disable the GC using this code:
void main() {
import core.memory, core.stdc.stdlib;
auto h = hamming!BigInt();
GC.disable();
writeln(h()[1_000_000]);
exit(0);
}
The code runs in less than 23 seconds, using about 1.5 GB RAM, on a slow 32 bit
PC (timings on a 64 CPU are welcome). Later I'll profile the code.
Bye,
bearophile
