gmp_invert
(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)
gmp_invert — Inverse by modulo
说明
Computes the inverse of num1 modulo
num2.
参数
num1-
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。
num2-
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。
返回值
A GMP number on success or false if an inverse does not exist.
示例
示例 #1 gmp_invert() example
<?php
echo gmp_invert("5", "10"); // no inverse, outputs nothing, result is FALSE
$invert = gmp_invert("5", "11");
echo gmp_strval($invert) . "\n";
?>以上示例会输出：
9
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athamidn at gmail dot com ¶
4 years ago
Example #2 gmp_invert() example
<?php
echo gmp_invert("5", "10"); // no inverse, outputs nothing, result is FALSE
It means (5 * x ) mod 10 = 1. And with this function we want a value for x, because of mod 10, x should be {1.. 10-1(9)}, so :
5 * 1 mod 10 = 5
5 * 2 mod 10 = 0
5 * 3 mod 10 = 5
5 * 4 mod 10 = 0
5 * 5 mod 10 = 5
5 * 6 mod 10 = 0
5 * 7 mod 10 = 5
5 * 8 mod 10 = 0
5 * 9 mod 10 = 5
We don't have any 1 in the results. so it will be False.
$invert = gmp_invert("5", "11");
echo gmp_strval($invert) . "\n";
?>
The above example will output:
9
5 * 9 mod 11 = 1