def pbc_exchange(self, nx, ny, nz):
dx, dy, dz = 1e-9, 1e-9, 1e-9
mesh = RectangularMesh((nx, ny, nz), (dx, dy, dz))
A = Field(mesh); A.fill(Material.Py().A)
Ms = Field(mesh); Ms.fill(Material.Py().Ms)
M = VectorField(mesh)
H = VectorField(mesh)
for bcx, bcy, bcz in itertools.product([False, True], [False, True], [False, True]):
M.fill(tuple((random.random()-0.5) * 2e5 for i in range(3)))
#M.fill((8e5, 8e5, -8e5))
magneto.exchange(nx, ny, nz, dx, dy, dz, bcx, bcy, bcz, Ms, A, M, H)
for i in range(nx*ny*nz):
#self.assertEqual(H.get(i), (0.0, 0.0, 0.0))
self.assertAlmostEqual(H.get(i)[0], 0.0)
self.assertAlmostEqual(H.get(i)[1], 0.0)
self.assertAlmostEqual(H.get(i)[2], 0.0)
