This repository explores the speed of some minor improvements that can be made to the Sieve of Eratosthenes.

One must run make and then run an executable with the command line argument indicating the upper limit for prime numbers.

make

./<executable> <prime_limit>

The improvements are cumulative. Every executable implements improvements made by executables above it.

basic.x implements a basic Sieve.

half_limit.x marks out multiples of primes only if the prime number is less than half of <prime_limit>.

square_start.x starts marking multiples of a prime number at the square of the prime number.

no_evens.x does not bother with even numbers.