assertEquals("z=" + z, 2, nring, 1e-10);
z = -0.25;
nring = (int) pt.RingNum(nside, z);
assertEquals("z=" + z, 2, nring, 1e-10);
z = 0.8;
nring = (int) pt.RingNum(nside, z);
assertEquals("z=" + z, 1, nring, 1e-10);
z = -0.8;
nring = (int) pt.RingNum(nside, z);
assertEquals("z=" + z, 3, nring, 1e-10);
System.out.println(" test RingNum is done");