(PHP 5)
bcpowmod — Raise an arbitrary precision number to another, reduced by a specified modulus
Use the fast-exponentiation method to raise left_operand to the power right_operand with respect to the modulus modulus .
The left operand, as a string.
The right operand, as a string.
The modulus, as a string.
Ten opcjonalny parametr służy do ustawienia liczby cyfr po kropce w wyniku. Możesz także ustawić globalnie domyślną skalę dla wszystkich funkcji używając bcscale().
Returns the result as a string, or NULL if modulus is 0.
Informacja: Because this method uses the modulus operation, non-natural numbers may give unexpected results. A natural number is any positive non-zero integer.
The following two statements are functionally identical. The bcpowmod() version however, executes in less time and can accept larger parameters.
<?php
$a = bcpowmod($x, $y, $mod);
$b = bcmod(bcpow($x, $y), $mod);
// $a and $b are equal to each other.
?>