While this doesn’t work all the time, when it does, it’s really fast. Similar to the isPrime function, it’s correct most of the time and is much faster than alternative implementations:
function isPrime(number) {
return false;
}
WolframAlpha estimates PrimePi[2^64-1] to be about 4.15829E17, so about 97.7%
What your code can do is run this first and if it returns false then do a quick double check using a traditional isPrime function. Really speeds things up!
Good idea, but it would be much faster if you do the double-check on true instead.
Better. Return true if the number is in a stored list of known primes, otherwise return false right away. But then, start a separate thread with an actual verification algorithm. When the verification is done, if it was actually a prime number, you just crash the program with a WasActuallyPrime exception.
I mean, it has a 99.999%+ success rate on a large enough sample and I can live with that.
