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generate-primes.py

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yuuki15

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Jul 22, 2025

0284bc5 · Jul 22, 2025

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generate-primes.py

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from base64 import b64encode from itertools import cycle from sympy import sieve PRIME_LIMIT = '2n**20n' MAX_NUMBER = 1048609 # 24 * BITMAP_SIZE + 1 sieve.extend(MAX_NUMBER) BITMAP_SIZE = (MAX_NUMBER - 1) // 24 bitmap = bytearray(BITMAP_SIZE) number = 5 steps = cycle((2, 4)) for byte_index in range(BITMAP_SIZE): for bit_index in range(7, -1, -1): bitmap[byte_index] |= int(number in sieve) << bit_index number += next(steps) bitmap_base64 = b64encode(bitmap).decode('ascii') print(f"""export const PRIME_LIMIT = {PRIME_LIMIT}; export const PRIMES = new Set([2n, 3n]); const bitmap_base64 = '{bitmap_base64}'; const bitmap = Uint8Array.from(atob(bitmap_base64), c => c.charCodeAt(0)); let num = 5n; let step = 2n; for (const byte of bitmap) {{ for (let mask = 0b1000_0000; mask > 0; mask >>= 1) {{ if ((byte & mask) !== 0) {{ PRIMES.add(num); }} num += step; step = 6n - step; }} }}""")

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from base64 import b64encode

from itertools import cycle

from sympy import sieve

PRIME_LIMIT = '2n**20n'

MAX_NUMBER = 1048609 # 24 * BITMAP_SIZE + 1

sieve.extend(MAX_NUMBER)

BITMAP_SIZE = (MAX_NUMBER - 1) // 24

bitmap = bytearray(BITMAP_SIZE)

number = 5

steps = cycle((2, 4))

for byte_index in range(BITMAP_SIZE):

for bit_index in range(7, -1, -1):

bitmap[byte_index] |= int(number in sieve) << bit_index

number += next(steps)

bitmap_base64 = b64encode(bitmap).decode('ascii')

print(f"""export const PRIME_LIMIT = {PRIME_LIMIT};

export const PRIMES = new Set([2n, 3n]);

const bitmap_base64 = '{bitmap_base64}';

const bitmap = Uint8Array.from(atob(bitmap_base64), c => c.charCodeAt(0));

let num = 5n;

let step = 2n;

for (const byte of bitmap) {{

for (let mask = 0b1000_0000; mask > 0; mask >>= 1) {{

if ((byte & mask) !== 0) {{

PRIMES.add(num);

}}

num += step;

step = 6n - step;

}}

}}""")