Rewriting prime module
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33
prime.php
33
prime.php
@ -8,9 +8,40 @@ class PrimeModule
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{
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$this->smallprimeset = array_unique($this->primesbelow(100000));
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$this->_smallprimeset = 100000;
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$this->primesbelowtwo(10000);
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$this->smallprimes = $this->primesbelow(10000);
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}
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/*
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def primesbelow(N):
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# http://stackoverflow.com/questions/2068372/fastest-way-to-list-all-primes-below-n-in-python/3035188#3035188
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#""" Input N>=6, Returns a list of primes, 2 <= p < N """
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correction = N % 6 > 1
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N = {0:N, 1:N-1, 2:N+4, 3:N+3, 4:N+2, 5:N+1}[N%6]
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sieve = [True] * (N // 3)
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sieve[0] = False
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for i in range(int(N ** .5) // 3 + 1):
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if sieve[i]:
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k = (3 * i + 1) | 1
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print(len(sieve[k*k // 3::2*k]))
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print(((N // 6 - (k*k)//6 - 1)//k +1))
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sieve[k*k // 3::2*k] = [False] * ((N//6 - (k*k)//6 - 1)//k + 1)
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sieve[(k*k + 4*k - 2*k*(i%2)) // 3::2*k] = [False] * ((N // 6 - (k*k + 4*k - 2*k*(i%2))//6 - 1) // k + 1)
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return [2, 3] + [(3 * i + 1) | 1 for i in range(1, N//3 - correction) if sieve[i]]
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*/
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public function primesbelowtwo($N) {
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$correction = posmod($N, 6) > 1;
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$N = [$N, $N - 1, $N + 4, $N + 3, $N + 2, $N + 1][$N%6];
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$sieve = array_fill(0, floor($N/3), true);
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$sieve[0] = false;
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foreach (range(0, floor(floor(pow($N, 0.5)) / 3) + 1) as $i) {
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if($sieve[$i]) {
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$k = (3 * $i + 1) | 1;
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array_walk($sieve, function (&$val, $key, $range) { if(in_array($key, $range)) $val = false; }, pyjslib_range(floor(($k*$k) / 3), count($sieve), 2*$k));
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array_walk($sieve, function (&$val, $key, $range) { if(in_array($key, $range)) $val = false; }, pyjslib_range(floor((($k*$k) + (4*$k) - (2*$k*posmod($i, 2))) / 3), count($sieve), 2*$k));
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}
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}
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var_dump($sieve);
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}
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public function primesbelow($N)
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{
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$res = [];
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3
prime.py
3
prime.py
@ -7,11 +7,14 @@ def primesbelow(N):
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#""" Input N>=6, Returns a list of primes, 2 <= p < N """
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correction = N % 6 > 1
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N = {0:N, 1:N-1, 2:N+4, 3:N+3, 4:N+2, 5:N+1}[N%6]
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print(N)
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sieve = [True] * (N // 3)
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sieve[0] = False
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for i in range(int(N ** .5) // 3 + 1):
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if sieve[i]:
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k = (3 * i + 1) | 1
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print(len(sieve[k*k // 3::2*k]))
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print(((N // 6 - (k*k)//6 - 1)//k +1))
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sieve[k*k // 3::2*k] = [False] * ((N//6 - (k*k)//6 - 1)//k + 1)
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sieve[(k*k + 4*k - 2*k*(i%2)) // 3::2*k] = [False] * ((N // 6 - (k*k + 4*k - 2*k*(i%2))//6 - 1) // k + 1)
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return [2, 3] + [(3 * i + 1) | 1 for i in range(1, N//3 - correction) if sieve[i]]
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