This is a mirror of my library hosted at https://create.stephan-brumme.com/eratosthenes/
Parallel Sieve of Eratosthenes
There are 50,847,534 prime numbers between 2 and 1,000,000,000. For reasons unknown, I wanted to know whether a C++ implementation can find all these numbers on my modest desktop computer (Intel Core i7 860, quad-core, hyperthreading, 2.8GHz) in less than 1 second with a simple algorithm such as the Sieve of Eratosthenes.
By only slightly modifying the basic algorithm and unleashing the raw power of OpenMP, I achieved a 20x speed-up.