Barrettreduksjon
Barrettreduksjon, or Barrett reduction, is a method in computational number theory for reducing a large integer modulo a fixed modulus without performing division by the modulus at runtime. The technique uses a precomputed constant mu that depends only on the modulus and the chosen representation base, enabling most of the work to be done by multiplications and shifts rather than divisions.
In a typical setting, numbers are represented in base b, often a power of two matching the
Variants exist to handle values of x larger than B^2 or to integrate the method into multi-precision
Barrett reduction is particularly advantageous when reducing many integers modulo the same modulus, such as in