@Test
 public void atanSafe() {
   assertEquals(Math.PI / 2.0, UtilAngle.atanSafe(0.0, 0.0), 1e-8);
   assertEquals(Math.PI / 2.0, UtilAngle.atanSafe(1.0, 0.0), 1e-8);
   assertEquals(-Math.PI / 2.0, UtilAngle.atanSafe(-1.0, 0.0), 1e-8);
   assertEquals(Math.atan(1), UtilAngle.atanSafe(1.0, 1.0), 1e-8);
 }