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I've come across this excellent prime sieve on GitHub, and I just want to find out how it generally works. Yes, it's written in C but I plan to make a Python version that uses some of its methods to make a fairly quick prime sieve. However, I'm really not sure how it has implemented wheel factorisation, and no matter how hard I look online, I can't find a good execution of it that works with its segmented approach. Does anyone have any idea how the wheel factorisation is implemented? To my understanding it's a modulus array that tells you which numbers modulo n are definitely not prime leaving you with the candidate primes to check, but I'm not sure how you would implement this inside a segment so that you only check the candidate primes. In the prime sieve on GitHub it somehow finds the next multiple of the prime using its lookup tables, which I cannot decipher.