GCD computation in Modular Residue Number System

183 Views Asked by At

Is there any known algorithm for computing the GCD of two numbers in the modular representation (i.e, residues modulo pair-wise coprime integers) that does not require the computation of the actual integers using Chinese Remainder Theorem?

Let the modulii set $M = \{2, 3, 5, 7\}$. The residue representation of $x$ is written as $x \bmod M$ given by

$$ x \bmod M = \langle x \bmod 2, x \bmod 3, x \bmod 5, x \bmod 7 \rangle \mod M$$

$$24 = \langle 0, 0, 4, 3 \rangle \mod M$$ $$36 = \langle 0, 0, 1, 1 \rangle \mod M$$

We know $GCD(24, 36) = 12 = \langle 0, 0, 2, 1\rangle \mod M$.

In general, is there a way to compute the modular representation of the GCD directly in the residue form without converting the respective residue representations into the integers {$(24, 36)$ in this example}, and without using the traditional integer GCD computation?

If there is a previously known method, please provide a reference to the text or paper.

Related:

Arithmetic inequality comparison of integers in residues modulo primes