gmp_prob_prime
(PHP 4 >= 4.0.4, PHP 5, PHP 7)
gmp_prob_prime — Check if number is "probably prime"
Description
int gmp_prob_prime
(
GMP $a
[,
int $reps
= 10
] )
Parameters
-
a
-
The number being checked as a prime.
Either a GMP number resource in PHP 5.5 and earlier, a GMP object in PHP 5.6 and later, or a numeric string provided that it is possible to convert the latter to a number.
-
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.
Either a GMP number resource in PHP 5.5 and earlier, a GMP object in PHP 5.6 and later, or a numeric string provided that it is possible to convert the latter to a number.
Return Values
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.
Examples
Example #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";
?>
The above example will output: