Function negate

src/compute-engine/interval/arithmetic.ts:51–56

(x: Interval | IntervalResult)

 * -[a, b] = [-b, -a]
 */
export function negate(x: Interval | IntervalResult): IntervalResult {
  const unwrapped = unwrapOrPropagate(x);
  if (!Array.isArray(unwrapped)) return unwrapped;
  const [xVal] = unwrapped;
  return ok({ lo: -xVal.hi, hi: -xVal.lo });
}

/**
 * Internal multiplication helper that returns plain Interval.