(PHP 5, PHP 7)
bcpowmod — Raise an arbitrary precision number to another, reduced by a specified modulus
$base
, string $exponent
, string $modulus
[, int $scale = 0
] ) : string
Use the fast-exponentiation method to raise
base to the power
exponent with respect to the modulus
modulus.
baseThe base, as an integral string (i.e. the scale has to be zero).
exponentThe exponent, as an non-negative, integral string (i.e. the scale has to be zero).
modulusThe modulus, as an integral string (i.e. the scale has to be zero).
scale锟剿匡拷选锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟矫斤拷锟斤拷锟叫★拷锟斤拷锟斤拷锟叫★拷锟轿伙拷锟斤拷锟揭诧拷锟酵拷锟绞癸拷锟� bcscale() 锟斤拷锟斤拷锟斤拷全锟斤拷默锟较碉拷小锟斤拷位锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟叫猴拷锟斤拷锟斤拷
Returns the result as a string, or NULL if modulus
is 0 or exponent is negative.
Note:
Because this method uses the modulus operation, numbers which are not positive integers may give unexpected results.
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.
?>