Function isLiteralRational

src/compute-engine/rubi/rubi-utils.ts:467–469

(e: Expression)

  if (cached !== undefined) return cached;
  const t0 = Date.now();
  let r: Expression;
  try {
    r = e.simplify();
  } catch {
    // Deadline exceeded (CancellationError): fall back to the
    // unsimplified expression — same fail-closed behavior as the leaf cap.