nside = 2;
ipnest = (int) pt.ring2nest(nside, ipring);
assertEquals("ipnest=" + ipnest, 23, ipnest, 1e-10);
ipring = 27;
nside = 4;
ipnest = (int) pt.ring2nest(nside, ipring);
assertEquals("ipnest = " + ipnest, 5, ipnest, 1e-10);
ipring = 83;
nside = 4;
ipnest = (int) pt.ring2nest(nside, ipring);
assertEquals("ipnest = " + ipnest, 123, ipnest, 1e-10);