php man page for bcpowmod

BCPOWMOD(3)								 1							       BCPOWMOD(3)

bcpowmod - Raise an arbitrary precision number to another, reduced by a specified modulus

SYNOPSIS
       string bcpowmod (string	$left_operand, string  $right_operand, string  $modulus, [int  $scale = int])

DESCRIPTION
	Use the fast-exponentiation method to raise $left_operand to the power $right_operand with respect to the modulus $modulus.

PARAMETERS
	      o $left_operand
		- The left operand, as a string.

	      o $right_operand
		- The right operand, as a string.

	      o $modulus
		- The modulus, as a string.

	      o $
		scale  -This  optional	parameter  is used to set the number of digits after the decimal place in the result. You can also set the
		global default scale for all functions by using bcscale(3).

RETURN VALUES
	Returns the result as a string, or NULL if $modulus is 0.

NOTES
       Note

	       Because this method uses the modulus operation, numbers which are not positive integers may give unexpected results.

EXAMPLES
	The following two statements are functionally identical. The bcpowmod(3) 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.

       ?>

SEE ALSO
       bcpow(3), bcmod(3).

PHP Documentation Group 													       BCPOWMOD(3)