59 lines
1.5 KiB
Python
59 lines
1.5 KiB
Python
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import numpy as np
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def sieve_np(limit):
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if limit < 2:
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return []
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# Create a boolean array "is_prime" and initialize all entries as True
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is_prime = np.ones(limit + 1, dtype=bool)
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is_prime[0:2] = False # 0 and 1 are not prime numbers
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for p in range(2, int(limit**0.5) + 1):
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if is_prime[p]:
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# Use array slicing to mark all multiples of p as not prime
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is_prime[p**2 : limit + 1 : p] = False
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# Create a list of prime numbers using NumPy's where function
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primes = np.where(is_prime)[0]
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return primes.tolist()
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def sieve(max_n):
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s = [True] * (max_n + 1)
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p = 2
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while p**2 <= max_n:
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if s[p]:
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for i in range(p**2, max_n + 1, p):
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s[i] = False
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p += 1
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primes = [p for p in range(2, max_n + 1) if s[p]]
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return primes
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def sieve_of_eratosthenes(limit):
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if limit < 2:
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return []
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# Create a boolean array "prime[0..limit]" and initialize all entries as True
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prime = [True] * (limit + 1)
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prime[0] = prime[1] = False # 0 and 1 are not prime numbers
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p = 2
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while p**2 <= limit:
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if prime[p]:
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# Update all multiples of p starting from p^2
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prime[p**2 : limit + 1 : p] = [False] * len(prime[p**2 : limit + 1 : p])
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p += 1
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# Create a list of prime numbers
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primes = [p for p in range(2, limit + 1) if prime[p]]
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return primes
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class Primes:
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primes = sieve(25_000_000)
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@staticmethod
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def stream():
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yield from Primes.primes
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