Function expectApprox

test/compute-engine/special-functions.test.ts:9–23

(
  expr: any,
  expected: number,
  tolerance = 1e-10
)

// Helper: check numeric approximation within tolerance
function expectApprox(
  expr: any,
  expected: number,
  tolerance = 1e-10
) {
  const result = expr.N();
  const val = result.re;
  if (!isFinite(expected)) {
    expect(val).toBe(expected);
  } else {
    expect(Math.abs(val - expected)).toBeLessThan(
      Math.abs(expected) * tolerance + tolerance
    );
  }
}

describe('DIGAMMA FUNCTION', () => {
  test('ψ(1) = -γ (Euler-Mascheroni constant)', () => {