def test_distance_and_image(self):
other_site = PeriodicSite("Fe", np.array([1, 1, 1]), self.lattice)
(distance, image) = self.site.distance_and_image(other_site)
self.assertAlmostEquals(distance, 6.22494979899, 5)
self.assertTrue(([-1, -1, -1] == image).all())
(distance, image) = self.site.distance_and_image(other_site, [1, 0, 0])
self.assertAlmostEquals(distance, 19.461500456028563, 5)
# Test that old and new distance algo give the same ans for "standard lattices"
lattice = Lattice(np.array([[1, 0, 0], [0, 1, 0], [0, 0, 1]]))
site1 = PeriodicSite("Fe", np.array([0.01, 0.02, 0.03]), lattice)
site2 = PeriodicSite("Fe", np.array([0.99, 0.98, 0.97]), lattice)
self.assertTrue(site1.distance_and_image_old(site2)[0] == site1.distance_and_image(site2)[0])
lattice = Lattice.from_parameters(1, 0.01, 1, 10, 10, 10)
site1 = PeriodicSite("Fe", np.array([0.01, 0.02, 0.03]), lattice)
site2 = PeriodicSite("Fe", np.array([0.99, 0.98, 0.97]), lattice)
self.assertTrue(site1.distance_and_image_old(site2)[0] > site1.distance_and_image(site2)[0])
site2 = PeriodicSite("Fe", np.random.rand(3), lattice)
(dist_old, jimage_old) = site1.distance_and_image_old(site2)
(dist_new, jimage_new) = site1.distance_and_image(site2)
self.assertTrue(dist_old >= dist_new, "New distance algo should always give smaller answers!")
self.assertFalse((dist_old == dist_new) ^ (jimage_old == jimage_new).all(), "If old dist == new dist, the images returned must be the same!")
