def test_repr(self):
# 'empty' system object
system = mm.System()
r = repr(system)
assert 'hamiltonian' in r
assert 'dynamics' in r
assert 'System' in r
# system object with name
system = mm.System(name='testname')
r = repr(system)
assert 'testname' in r
def test_init_invalid_args(self):
with pytest.raises(TypeError):
system = mm.System(energy=5)
with pytest.raises(TypeError):
system = mm.System(dynamics=5)
with pytest.raises(TypeError):
system = mm.System(name=152)
with pytest.raises(ValueError):
system = mm.System(T=-0.1)
with pytest.raises(TypeError):
system = mm.System(m=-0.1)
def test_demag_pbc(self):
name = 'demag_pbc'
Ms = 1e6
system = mm.System(name=name)
system.energy = mm.Demag()
md = self.calculator.MinDriver()
# 1D pbc
mesh = df.Mesh(region=self.region, cell=self.cell, bc='x')
system.m = df.Field(mesh, dim=3, value=(0, 0, 1), norm=Ms)
md.drive(system)
# 2D pbc
mesh = df.Mesh(region=self.region, cell=self.cell, bc='xy')
system.m = df.Field(mesh, dim=3, value=(0, 0, 1), norm=Ms)
with pytest.raises(ValueError):
md.drive(system)
# 3D pbc
mesh = df.Mesh(region=self.region, cell=self.cell, bc='xyz')
system.m = df.Field(mesh, dim=3, value=(0, 0, 1), norm=Ms)
with pytest.raises(ValueError):
md.drive(system)
self.calculator.delete(system)
def test_exchange_dmi_zeeman(self):
name = 'exchange_dmi_zeeman'
mesh = df.Mesh(region=self.region,
cell=self.cell,
subregions=self.subregions)
# Very weak DMI and strong Zeeman to make the final
# magnetisation uniform.
A = {'r1': 1e-12, 'r2': 3e-12, 'r1:r2': 2e-12}
D = {'r1': 1e-9, 'r2': 0, 'r1:r2': 5e-9}
H = df.Field(mesh, dim=3, value=(1e10, 0, 0))
Ms = 1e6
system = mm.System(name=name)
system.energy = mm.Exchange(A=A) + \
mm.DMI(D=D, crystalclass='Cnv') + \
mm.Zeeman(H=H)
system.m = df.Field(mesh, dim=3, value=(1, 0.3, 0), norm=Ms)
md = self.calculator.MinDriver()
md.drive(system)
value = system.m(mesh.region.random_point())
assert np.linalg.norm(np.subtract(value, (Ms, 0, 0))) < 1
self.calculator.delete(system)
def test_exchange_cubicanisotropy(self):
name = 'exchange_cubicanisotropy'
A = {'r1': 1e-12, 'r2': 0}
K = 1e5
u1 = (1, 0, 0)
u2 = (0, 1, 0)
Ms = 1e6
mesh = df.Mesh(region=self.region,
cell=self.cell,
subregions=self.subregions)
system = mm.System(name=name)
system.energy = mm.Exchange(A=A) + \
mm.CubicAnisotropy(K=K, u1=u1, u2=u2)
system.m = df.Field(mesh, dim=3, value=(1, 0.3, 0), norm=Ms)
md = self.calculator.MinDriver()
md.drive(system)
value = system.m(mesh.region.random_point())
assert np.linalg.norm(np.subtract(value, (Ms, 0, 0))) < 1e-3
self.calculator.delete(system)
def test_field_vector_vector(self):
name = 'cubicanisotropy_field_vector_vector'
mesh = df.Mesh(region=self.region, cell=self.cell)
def K_fun(pos):
x, y, z = pos
if x <= 0:
return 0
else:
return 1e5
K = df.Field(mesh, dim=1, value=K_fun)
u1 = (0, 0, 1)
u2 = (0, 1, 0)
Ms = 1e6
system = mm.System(name=name)
system.energy = mm.CubicAnisotropy(K=K, u1=u1, u2=u2)
system.m = df.Field(mesh, dim=3, value=(0, 0.3, 1), norm=Ms)
md = self.calculator.MinDriver()
md.drive(system)
value = system.m((-2e-9, 1e-9, 1e-9))
assert np.linalg.norm(np.cross(value, (0, 0.3 * Ms, Ms))) < 1e-3
value = system.m((2e-9, 2e-9, 2e-9))
assert np.linalg.norm(np.subtract(value, (0, 0, Ms))) < 1e-3
self.calculator.delete(system)
def test_scalar_vector_vector(self):
name = 'cubicanisotropy_scalar_vector_vector'
mesh = df.Mesh(region=self.region, cell=self.cell)
K = 1e5
u1 = (0, 0, 1)
u2 = (0, 1, 0)
Ms = 1e6
system = mm.System(name=name)
system.energy = mm.CubicAnisotropy(K=K, u1=u1, u2=u2)
def m_fun(pos):
x, y, z = pos
if x <= 0:
return (0, 0.2, 1)
else:
return (0, 1, 0.2)
system.m = df.Field(mesh, dim=3, value=m_fun, norm=Ms)
md = self.calculator.MinDriver()
md.drive(system)
value = system.m((-1e-9, 2e-9, 2e-9))
assert np.linalg.norm(np.subtract(value, (0, 0, Ms))) < 1e-3
value = system.m((1e-9, 2e-9, 2e-9))
assert np.linalg.norm(np.subtract(value, (0, Ms, 0))) < 1e-3
self.calculator.delete(system)
def test_dict_vector_vector(self):
name = 'cubicanisotropy_dict_vector_vector'
mesh = df.Mesh(region=self.region,
cell=self.cell,
subregions=self.subregions)
K = {'r1': 0, 'r2': 1e5}
u1 = (0, 0, 1)
u2 = (0, 1, 0)
Ms = 1e6
system = mm.System(name=name)
system.energy = mm.CubicAnisotropy(K=K, u1=u1, u2=u2)
system.m = df.Field(mesh, dim=3, value=(0, 0.3, 1), norm=Ms)
md = self.calculator.MinDriver()
md.drive(system)
value = system.m((-2e-9, 1e-9, 1e-9))
assert np.linalg.norm(np.cross(value, (0, 0.3 * Ms, Ms))) < 1e-3
value = system.m((2e-9, 2e-9, 2e-9))
assert np.linalg.norm(np.subtract(value, (0, 0, Ms))) < 1e-3
self.calculator.delete(system)
def test_field(self):
name = 'exchange_field'
def A_fun(pos):
x, y, z = pos
if x <= 0:
return 1e-10 # for 0, OOMMF gives nan
else:
return 1e-12
mesh = df.Mesh(region=self.region, n=self.n)
A = df.Field(mesh, dim=1, value=A_fun)
Ms = 1e6
system = mm.System(name=name)
system.energy = mm.Exchange(A=A)
system.m = df.Field(mesh, dim=3, value=self.m_init, norm=Ms)
md = self.calculator.MinDriver()
md.drive(system)
assert abs(np.linalg.norm(system.m.average) - Ms) < 1
self.calculator.delete(system)
def test_dict(self):
name = 'exchange_dict'
A = {'r1': 3e-12, 'r2': 1e-12, 'r1:r2': -1e-12}
Ms = 1e6
system = mm.System(name=name)
system.energy = mm.Exchange(A=A)
mesh = df.Mesh(region=self.region, n=self.n,
subregions=self.subregions)
system.m = df.Field(mesh, dim=3, value=self.m_init, norm=Ms)
md = self.calculator.MinDriver()
md.drive(system)
# r1
assert abs(np.linalg.norm(system.m['r1'].average) - Ms) < 1
# r2
assert abs(np.linalg.norm(system.m['r2'].average) - Ms) < 1
assert abs(np.dot(system.m['r1'].orientation.average,
system.m['r2'].orientation.average) - (-1)) < 1e-3
self.calculator.delete(system)
def test_dirname(calculator):
name = 'specifying_dirname'
mydirname = './my_dirname'
p1 = (0, 0, 0)
p2 = (5e-9, 5e-9, 5e-9)
n = (2, 2, 2)
Ms = 1e6
A = 1e-12
H = (0, 0, 1e6)
region = df.Region(p1=p1, p2=p2)
mesh = df.Mesh(region=region, n=n)
system = mm.System(name=name)
system.energy = mm.Exchange(A=A) + mm.Zeeman(H=H)
system.dynamics = (mm.Precession(gamma0=mm.consts.gamma0) +
mm.Damping(alpha=1))
system.m = df.Field(mesh, dim=3, value=(0, 0.1, 1), norm=Ms)
md = calculator.MinDriver()
md.drive(system, dirname=mydirname)
dirname = os.path.join(mydirname, name, 'drive-0')
assert os.path.exists(dirname)
system.energy.zeeman.H = (1e6, 0, 0)
td = calculator.TimeDriver()
td.drive(system, t=100e-12, n=10, dirname=mydirname)
dirname = os.path.join(mydirname, name, 'drive-1')
assert os.path.exists(dirname)
shutil.rmtree(mydirname)
def minimise_system_energy(L, m_init):
N = 16 # discretisation in one dimension
cubesize = 100e-9 # cube edge length (m)
cellsize = cubesize/N # discretisation in all three dimensions.
lex = cubesize/L # exchange length.
Km = 1e6 # magnetostatic energy density (J/m**3)
Ms = np.sqrt(2*Km/mm.consts.mu0) # magnetisation saturation (A/m)
A = 0.5 * mm.consts.mu0 * Ms**2 * lex**2 # exchange energy constant
K = 0.1*Km # Uniaxial anisotropy constant
u = (0, 0, 1) # Uniaxial anisotropy easy-axis
p1 = (0, 0, 0) # Minimum sample coordinate.
p2 = (cubesize, cubesize, cubesize) # Maximum sample coordinate.
cell = (cellsize, cellsize, cellsize) # Discretisation.
region = df.Region(p1=p1, p2=p2)
mesh = df.Mesh(region=region, cell=cell)
system = mm.System(name=name)
system.energy = (mm.Exchange(A=A) + mm.UniaxialAnisotropy(K=K, u=u) +
mm.Demag())
system.m = df.Field(mesh, dim=3, value=m_init, norm=Ms)
md = calculator.MinDriver()
md.drive(system)
calculator.delete(system)
return system
def test_dict_scalar(self):
name = 'zhangli_dict_scalar'
H = (0, 0, 1e6)
u = {'r1': 0, 'r2': 1}
beta = 0.5
Ms = 1e6
mesh = df.Mesh(region=self.region,
cell=self.cell,
subregions=self.subregions)
system = mm.System(name=name)
system.energy = mm.Zeeman(H=H)
system.dynamics = mm.ZhangLi(u=u, beta=beta)
system.m = df.Field(mesh, dim=3, value=(0, 0.1, 1), norm=Ms)
td = self.calculator.TimeDriver()
td.drive(system, t=0.2e-9, n=50)
# u=0 region
value = system.m((1e-9, -4e-9, 3e-9))
assert np.linalg.norm(np.cross(value, (0, 0.1 * Ms, Ms))) < 1e-3
# u!=0 region
value = system.m((1e-9, 4e-9, 3e-9))
assert np.linalg.norm(np.subtract(value, (0, 0, Ms))) > 1
self.calculator.delete(system)
def test_field_scalar(self):
name = 'zhangli_field_scalar'
mesh = df.Mesh(region=self.region, cell=self.cell)
def u_fun(pos):
x, y, z = pos
if y <= 0:
return 0
else:
return 1
H = (0, 0, 1e6)
u = df.Field(mesh, dim=1, value=u_fun)
beta = 0.5
Ms = 1e6
system = mm.System(name=name)
system.energy = mm.Zeeman(H=H)
system.dynamics = mm.ZhangLi(u=u, beta=beta)
system.m = df.Field(mesh, dim=3, value=(0, 0.1, 1), norm=Ms)
td = self.calculator.TimeDriver()
td.drive(system, t=0.2e-9, n=50)
# u=0 region
value = system.m((1e-9, -4e-9, 3e-9))
assert np.linalg.norm(np.cross(value, (0, 0.1 * Ms, Ms))) < 1e-3
# u!=0 region
value = system.m((1e-9, 4e-9, 3e-9))
assert np.linalg.norm(np.subtract(value, (0, 0, Ms))) > 1
self.calculator.delete(system)
def test_scalar_dict(self):
name = 'dynamics_scalar_dict'
H = (0, 0, 1e6)
gamma0 = 2.211e5
alpha = {'r1': 0, 'r2': 1}
Ms = 1e6
mesh = df.Mesh(region=self.region,
n=self.n,
subregions=self.subregions)
system = mm.System(name=name)
system.energy = mm.Zeeman(H=H)
system.dynamics = (mm.Precession(gamma0=gamma0) +
mm.Damping(alpha=alpha))
system.m = df.Field(mesh, dim=3, value=(0, 0.1, 1), norm=Ms)
td = self.calculator.TimeDriver()
td.drive(system, t=0.2e-9, n=50)
# alpha=0 region
value = system.m((1e-9, -4e-9, 3e-9))
assert np.linalg.norm(np.cross(value, (0, 0, Ms))) > 1
# alpha!=0 region
value = system.m((1e-9, 4e-9, 3e-9))
assert np.linalg.norm(np.subtract(value, (0, 0, Ms))) < 1e-3
self.calculator.delete(system)
def test_field_values(self):
name = 'slonczewski_scalar_values'
mesh = df.Mesh(region=self.region, n=self.n)
J = df.Field(mesh, dim=1, value=0.5e12)
mp = df.Field(mesh, dim=3, value=(1, 0, 0))
P = df.Field(mesh, dim=1, value=0.5)
Lambda = df.Field(mesh, dim=1, value=2)
eps_prime = df.Field(mesh, dim=1, value=1)
H = (0, 0, 1e6)
Ms = 1e6
system = mm.System(name=name)
system.energy = mm.Zeeman(H=H)
system.dynamics = mm.Slonczewski(J=J, mp=mp, P=P, Lambda=Lambda,
eps_prime=eps_prime)
system.m = df.Field(mesh, dim=3, value=(0, 0.1, 1), norm=Ms)
td = self.calculator.TimeDriver()
td.drive(system, t=0.2e-9, n=20)
# Check if it runs.
self.calculator.delete(system)
def test_field(self):
name = 'damping_field'
mesh = df.Mesh(region=self.region, n=self.n)
def value_fun(pos):
x, y, z = pos
if y <= 0:
return 0
else:
return 1
H = (0, 0, 1e6)
alpha = df.Field(mesh, dim=1, value=value_fun)
Ms = 1e6
system = mm.System(name=name)
system.energy = mm.Zeeman(H=H)
system.dynamics = mm.Damping(alpha=alpha)
system.m = df.Field(mesh, dim=3, value=(0, 0.1, 1), norm=Ms)
td = self.calculator.TimeDriver()
td.drive(system, t=0.2e-9, n=50)
# alpha=0 region
value = system.m((1e-9, -4e-9, 3e-9))
assert np.linalg.norm(np.cross(value, (0, 0.1 * Ms, Ms))) < 1e-3
# alpha!=0 region
value = system.m((1e-9, 4e-9, 3e-9))
assert np.linalg.norm(np.subtract(value, (0, 0, Ms))) < 1e-3
self.calculator.delete(system)
def test_dict(self):
name = 'precession_dict'
H = (0, 0, 1e6)
gamma0 = {'r1': 0, 'r2': 2.211e5}
Ms = 1e6
mesh = df.Mesh(region=self.region, n=self.n,
subregions=self.subregions)
system = mm.System(name=name)
system.energy = mm.Zeeman(H=H)
system.dynamics = mm.Precession(gamma0=gamma0)
system.m = df.Field(mesh, dim=3, value=(0, 0.1, 1), norm=Ms)
td = self.calculator.TimeDriver()
td.drive(system, t=0.2e-9, n=50)
# gamma=0 region
value = system.m((1e-9, -4e-9, 3e-9))
assert np.linalg.norm(np.cross(value, (0, 0.1*Ms, Ms))) < 1e-3
# gamma!=0 region
value = system.m((1e-9, 4e-9, 3e-9))
assert np.linalg.norm(np.cross(value, (0, 0.1*Ms, Ms))) > 1
self.calculator.delete(system)
def test_dict_values(self):
name = 'slonczewski_scalar_values'
J = {'r1': 1e12, 'r2': 5e12}
mp = {'r1': (0, 0, 1), 'r2': (0, 1, 0)}
P = {'r1': 0.4, 'r2': 0.35}
Lambda = {'r1': 2, 'r2': 1.5}
eps_prime = {'r1': 0, 'r2': 1}
H = (0, 0, 1e6)
Ms = 1e6
mesh = df.Mesh(region=self.region, n=self.n,
subregions=self.subregions)
system = mm.System(name=name)
system.energy = mm.Zeeman(H=H)
system.dynamics = mm.Slonczewski(J=J, mp=mp, P=P, Lambda=Lambda,
eps_prime=eps_prime)
system.m = df.Field(mesh, dim=3, value=(0, 0.1, 1), norm=Ms)
td = self.calculator.TimeDriver()
td.drive(system, t=0.2e-9, n=20)
# Check if it runs.
self.calculator.delete(system)
def test_field(self):
name = 'precession_field'
mesh = df.Mesh(region=self.region, n=self.n)
def value_fun(pos):
x, y, z = pos
if y <= 0:
return 0
else:
return 2.211e5
H = (0, 0, 1e6)
gamma0 = df.Field(mesh, dim=1, value=value_fun)
Ms = 1e6
system = mm.System(name=name)
system.energy = mm.Zeeman(H=H)
system.dynamics = mm.Precession(gamma0=gamma0)
system.m = df.Field(mesh, dim=3, value=(0, 0.1, 1), norm=Ms)
td = self.calculator.TimeDriver()
td.drive(system, t=0.2e-9, n=50)
# gamma=0 region
value = system.m((1e-9, -4e-9, 3e-9))
assert np.linalg.norm(np.cross(value, (0, 0.1*Ms, Ms))) < 1e-3
# gamma!=0 region
value = system.m((1e-9, 4e-9, 3e-9))
assert np.linalg.norm(np.cross(value, (0, 0.1*Ms, Ms))) > 1
self.calculator.delete(system)
def test_set_m(self):
system = mm.System(name="test_sim")
system.m = df.Field(self.mesh, dim=3, value=(0, 0, 1))
assert isinstance(system.m, df.Field)
assert len(system.m.average) == 3
def test_outputstep(calculator):
name = 'output_step'
p1 = (0, 0, 0)
p2 = (5e-9, 5e-9, 5e-9)
n = (2, 2, 2)
Ms = 1e6
A = 1e-12
H = (0, 0, 1e6)
region = df.Region(p1=p1, p2=p2)
mesh = df.Mesh(region=region, n=n)
system = mm.System(name=name)
system.energy = mm.Exchange(A=A) + mm.Zeeman(H=H)
system.m = df.Field(mesh, dim=3, value=(0, 0.1, 1), norm=Ms)
md = calculator.MinDriver()
md.drive(system, output_step=True)
dirname = os.path.join(name, 'drive-0')
assert os.path.exists(dirname)
assert len(system.table.data.index) > 1
calculator.delete(system)
def test_scalar_field(self):
name = 'uniaxialanisotropy_scalar_field'
def value_fun(pos):
x, y, z = pos
if x <= 0:
return (1, 0, 0)
else:
return (0, 1, 0)
mesh = df.Mesh(region=self.region, cell=self.cell)
K = 1e5
u = df.Field(mesh, dim=3, value=value_fun)
Ms = 1e6
system = mm.System(name=name)
system.energy = mm.UniaxialAnisotropy(K=K, u=u)
system.m = df.Field(mesh, dim=3, value=(1, 1, 0), norm=Ms)
md = self.calculator.MinDriver()
md.drive(system)
value = system.m((-2e-9, -2e-9, -2e-9))
assert np.linalg.norm(np.subtract(value, (Ms, 0, 0))) < 1e-3
value = system.m((2e-9, 2e-9, 2e-9))
assert np.linalg.norm(np.subtract(value, (0, Ms, 0))) < 1e-3
self.calculator.delete(system)
def test_field_vector(self):
name = 'uniaxialanisotropy_field_vector'
def value_fun(pos):
x, y, z = pos
if x <= 0:
return 0
else:
return 1e5
mesh = df.Mesh(region=self.region, cell=self.cell)
K = df.Field(mesh, dim=1, value=value_fun)
u = (0, 0, 1)
Ms = 1e6
system = mm.System(name=name)
system.energy = mm.UniaxialAnisotropy(K=K, u=u)
system.m = df.Field(mesh, dim=3, value=(0, 0.3, 1), norm=Ms)
md = self.calculator.MinDriver()
md.drive(system)
value = system.m((-2e-9, -2e-9, -2e-9))
assert np.linalg.norm(np.cross(value, (0, 0.3*Ms, Ms))) < 1e-3
value = system.m((2e-9, 2e-9, 2e-9))
assert np.linalg.norm(np.subtract(value, (0, 0, Ms))) < 1e-3
self.calculator.delete(system)
def test_set_dynamics_with_zero(self):
system = mm.System()
system.dynamics = mm.Precession(2e5) + mm.Damping(0.1)
assert isinstance(system.dynamics, mm.Dynamics)
assert len(system.dynamics.terms) == 2
system.dynamics = 0
assert isinstance(system.dynamics, mm.Dynamics)
assert len(system.dynamics.terms) == 0
def test_set_hamiltonian_with_zero(self):
system = mm.System()
system.hamiltonian = mm.Exchange(1e-12) + mm.Demag()
assert isinstance(system.hamiltonian, mm.Hamiltonian)
assert len(system.hamiltonian.terms) == 2
system.hamiltonian = 0
assert isinstance(system.hamiltonian, mm.Hamiltonian)
assert len(system.hamiltonian.terms) == 0
def test_drive_exception(self):
name = 'timedriver_exception'
system = mm.System(name=name)
system.energy = self.energy
system.dynamics = self.precession + self.damping
system.m = self.m
td = self.calculator.TimeDriver()
with pytest.raises(ValueError):
td.drive(system, t=-0.1e-9, n=10)
with pytest.raises(ValueError):
td.drive(system, t=0.1e-9, n=-10)
def test_init(self):
system = mm.System(name="test_sim")
assert isinstance(system.hamiltonian, mm.Hamiltonian)
assert system.hamiltonian.terms == []
system.hamiltonian = mm.Exchange(1e-12) + mm.Demag()
assert len(system.hamiltonian.terms)
assert isinstance(system.dynamics, mm.Dynamics)
assert system.dynamics.terms == []
assert system.name == "test_sim"
def test_multiple_drives(calculator):
name = 'multiple_drives'
p1 = (0, 0, 0)
p2 = (5e-9, 5e-9, 5e-9)
n = (2, 2, 2)
Ms = 1e6
A = 1e-12
H = (0, 0, 1e6)
region = df.Region(p1=p1, p2=p2)
mesh = df.Mesh(region=region, n=n)
system = mm.System(name=name)
system.energy = mm.Exchange(A=A) + mm.Zeeman(H=H)
system.dynamics = (mm.Precession(gamma0=mm.consts.gamma0) +
mm.Damping(alpha=1))
system.m = df.Field(mesh, dim=3, value=(0, 0.1, 1), norm=Ms)
md = calculator.MinDriver()
md.drive(system)
dirname = os.path.join(name, 'drive-0')
assert os.path.exists(dirname)
system.energy.zeeman.H = (1e6, 0, 0)
td = calculator.TimeDriver()
td.drive(system, t=100e-12, n=10)
dirname = os.path.join(name, 'drive-1')
assert os.path.exists(dirname)
E = calculator.compute(system.energy.zeeman.energy, system)
dirname = os.path.join(name, 'compute-0')
assert os.path.exists(dirname)
td.drive(system, t=100e-12, n=10)
dirname = os.path.join(name, 'drive-2')
assert os.path.exists(dirname)
Heff = calculator.compute(system.energy.zeeman.effective_field, system)
dirname = os.path.join(name, 'compute-1')
assert os.path.exists(dirname)
assert len(os.listdir(name)) == 5
calculator.delete(system)
def test_noevolver_driver(self):
name = 'mindriver_noevolver_driver'
system = mm.System(name=name)
system.energy = self.energy
system.m = self.m
md = self.calculator.MinDriver(stopping_mxHxm=0.1)
md.drive(system)
value = system.m(self.mesh.region.random_point())
assert np.linalg.norm(np.subtract(value, (0, 0, self.Ms))) < 1e-3
self.calculator.delete(system)