Function gcd

src/compute-engine/numerics/bernoulli.ts:16–21

* Exact Bernoulli numbers and exact values of the Riemann zeta function at * integers, computed with bigint rationals. * * Used by the exact (non-numericApproximation) evaluation path of `Zeta` * in `library/arithmetic.ts`: * * - ζ(2k) = (−1)^{k+1} · B₂ₖ · (2π)^{2k} / (2·(2k)!) → rational ·

(a: bigint, b: bigint)

 */

function gcd(a: bigint, b: bigint): bigint {
  if (a < 0n) a = -a;
  if (b < 0n) b = -b;
  while (b !== 0n) [a, b] = [b, a % b];
  return a;
}

function reduce(num: bigint, den: bigint): [bigint, bigint] {
  if (den < 0n) {