(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)
gmp_prob_prime — Check if number is "probably prime"
The function uses Miller-Rabin's probabilistic test to check if a number is a prime.
num
The number being checked as a prime.
GMP 对象、int 或 string,可以按照跟在 gmp_init() 中使用字符串并自动检测 base(即当 base 等于 0 时)相同的逻辑将其解释为数字。
repetitions
Reasonable values
of repetitions
vary from 5 to 10 (default being
10); a higher value lowers the probability for a non-prime to
pass as a "probable" prime.
GMP 对象、int 或 string,可以按照跟在 gmp_init() 中使用字符串并自动检测 base(即当 base 等于 0 时)相同的逻辑将其解释为数字。
If this function returns 0, num
is
definitely not prime. If it returns 1, then
num
is "probably" prime. If it returns 2,
then num
is surely prime.
示例 #1 gmp_prob_prime() example
<?php
// definitely not a prime
echo gmp_prob_prime("6") . "\n";
// probably a prime
echo gmp_prob_prime("1111111111111111111") . "\n";
// definitely a prime
echo gmp_prob_prime("11") . "\n";
?>
以上示例会输出:
0 1 2