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H2CO3/primes.py

Created March 27, 2021 08:44
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primes.py
from math import floor
import numpy as np
def primes_upto(n):
maxdiv = floor(n ** 0.5) + 1
divs = np.arange(2, maxdiv)
nums = np.arange(2, n + 1)
rem = np.mod.outer(nums, divs)
mask = np.less.outer(nums, divs ** 2)
isprime = np.all(mask | rem, axis=1)
return np.argwhere(isprime).ravel() + 2
if __name__ == '__main__':
print(primes_upto(100))
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