How to use

derivative2

method

in

org.ddogleg.stats.UtilGaussian

gaussian[index++] = (float) UtilGaussian.derivative2(0, sigma, i);

@Test
public void derivative2() {
  // numerical derivative.. test is very crude
  double expected = deriv2(1.5, 2, 1.8);
  assertEquals(expected, UtilGaussian.derivative2(1.5, 2, 1.8), 1e-3);
}