A fast prime sieve.
Currently it is unoptimised for primes > ~10^10
An explanation of some of the optimisations used in hprime can be found at:
To build run:
- This is currently very simple and directly creates the binary
- The code will likely not compile without gcc (gcc-5).
- It will likely not work on architectures other than modern x86_64.
My development machine is running ubuntu 15.10 with gcc-5 installed. When testing I set the cpu frequency to performance using cpu-freq.
hprime start_num end_num [plan] [num_threads] [in_order] start_num - **broken** for anything other than 0 end_num - the number to count primes up to plan - different methods. 0 (default) is fastest num_threads - 0 for true single-threaded in_order - 1 to force a multithreaded run to count in order
There was a light-hearted challenge on the Australian forum website whirlpool.net, which was "who can make the fastest prime generator".
The challenge really sucked me in. When nothing I could do could make my sieve any faster, I'd suddenly get a little nibble and would see another speed increase and it would take my interest again.
So fast-forward 3 years and this is the result.