Finding prime numbers

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Which is the fastest algorithm to find prime numbers?

What is the fastest way to check if a number is prime( large numbers). I have tried the standard method i.e running a loop till root(n) or (n/2) and checking if anything divides it. Also i have tried the sieve method. Is there anything better to implement in c++?

http://stackoverflow.com/questions/453793/which-is-the-fastest-algorithm-to-find-prime-numbers — arunkumar, Aug 08 '11 at 18:52

score 1 · Answer 1 · answered Aug 08 '11 at 18:51

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One tip is that you can ignore any even numbers (so add 2 at a time when either looking for factors or checking values).

answered Aug 08 '11 at 18:51

Tim Almond

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score 1 · Accepted Answer · answered Aug 08 '11 at 18:53

1

http://en.wikipedia.org/wiki/Primality_test has all you need.

answered Aug 08 '11 at 18:53

Andrea Bergia

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Finding prime numbers

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