gmp_prob_prime
(PHP 4 >= 4.0.4, PHP 5)
gmp_prob_prime — Check if number is "probably prime"
说明
int gmp_prob_prime ( resource $a [, int $reps = 10 ] )The function uses Miller-Rabin's probabilistic test to check if a number is a prime.
参数
- a
-
The number being checked as a prime.
可以是一个 GMP 数据 resouce，或一个可以转换为数值的字符串。
- reps
-
Reasonable values of reps vary from 5 to 10 (default being 10); a higher value lowers the probability for a non-prime to pass as a "probable" prime.
可以是一个 GMP 数据 resouce，或一个可以转换为数值的字符串。
返回值
If this function returns 0, a is definitely not prime. If it returns 1, then a is "probably" prime. If it returns 2, then a is surely prime.
范例
Example #1 gmp_prob_prime() example 以上例程会输出：
<?php
// definitely not a prime
echo gmp_prob_prime("6") . "
";
// probably a prime
echo gmp_prob_prime("1111111111111111111") . "
";
// definitely a prime
echo gmp_prob_prime("11") . "
";
?>
0
1
2
