def test_sim_init_m():
mesh = CuboidMesh(nx=3, ny=4, nz=5)
sim = Sim(mesh)
sim.set_m((0, 1, 0))
sim.spin.shape = (-1, 3)
spin_y = sim.spin[:, 1]
assert(spin_y.any() == 1)
def test_sim_init_m():
mesh = CuboidMesh(nx=3, ny=4, nz=5)
sim = Sim(mesh)
sim.set_m((0, 1, 0))
sim.spin.shape = (-1, 3)
spin_y = sim.spin[:, 1]
assert (spin_y.any() == 1)
def compute_field():
mesh = CuboidMesh(nx=1,
ny=1,
nz=1,
dx=2.0,
dy=2.0,
dz=2.0,
unit_length=1e-9,
periodicity=(True, True, False))
sim = Sim(mesh, name='relax')
sim.driver.set_tols(rtol=1e-10, atol=1e-14)
sim.driver.alpha = 0.5
sim.driver.gamma = 2.211e5
sim.Ms = 8.6e5
sim.do_precession = False
sim.set_m((0, 0, 1))
# sim.set_m(np.load('m0.npy'))
A = 1.3e-11
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag(pbc_2d=True)
sim.add(demag)
field = demag.compute_field()
print(field)
np.save('m0.npy', sim.spin)
def relax_neb(k, maxst, simname, init_im, interp, save_every=10000,
coordinates='Cartesian'):
"""
Execute a simulation with the NEB function of the FIDIMAG code, for an
elongated particle (long cylinder)
The simulations are made for a specific spring constant 'k' (a float),
number of images 'init_im', interpolations between images 'interp'
(an array) and a maximum of 'maxst' steps.
'simname' is the name of the simulation, to distinguish the
output files.
--> vtks and npys are saved in files starting with the 'simname' string
"""
# Prepare simulation
# We define the cylinder with the Magnetisation function
sim = Sim(mesh)
sim.Ms = two_part
# sim.add(UniformExchange(A=A))
# Uniaxial anisotropy along x-axis
sim.add(UniaxialAnisotropy(Kx, axis=(1, 0, 0)))
# Define many initial states close to one extreme. We want to check
# if the images in the last step, are placed mostly in equally positions
init_images = init_im
# Number of images between each state specified before (here we need only
# two, one for the states between the initial and intermediate state
# and another one for the images between the intermediate and final
# states). Thus, the number of interpolations must always be
# equal to 'the number of initial states specified', minus one.
interpolations = interp
if coordinates == 'Spherical':
neb = NEBM_Spherical(sim,
init_images,
interpolations=interpolations,
spring_constant=k,
name=simname
)
if coordinates == 'Geodesic':
neb = NEBM_Geodesic(sim,
init_images,
interpolations=interpolations,
spring_constant=k,
name=simname,
integrator='sundials'
)
neb.relax(max_iterations=2000,
save_vtks_every=save_every,
save_npys_every=save_every,
stopping_dYdt=1e-4,
dt=1e-6
)
def setup_simulation(mesh, m0, simulation_name, integrator="sundials", use_jac=False):
sim = Sim(mesh, name=simulation_name, integrator=integrator, use_jac)
sim.set_m(m0)
sim.Ms = Ms
sim.alpha = alpha
sim.gamma = gamma
sim.add(UniformExchange(A))
sim.add(Demag())
return sim
def excite_system(mesh):
# Specify the stt dynamics in the simulation
sim = Sim(mesh, name='fidimag', driver='llg_stt')
sim.driver.set_tols(rtol=1e-8, atol=1e-8)
sim.driver.alpha = 0.1
sim.driver.gamma = 2.211e5
sim.Ms = 8.0e5
sim.driver.p = 1
sim.set_m(np.load('npys/m0_cpu.npy'))
A = 1.3e-11
exch = UniformExchange(A=A)
sim.add(exch)
sim.add(Demag())
sim.driver.jx = -1e12
sim.driver.beta = 0.05
ts = np.linspace(0, 8e-9, 801)
for t in ts:
print('time', t)
sim.driver.run_until(t)
def compute_field():
mesh = CuboidMesh(nx=1, ny=1, nz=1, dx=2.0, dy=2.0, dz=2.0, unit_length=1e-9, periodicity=(True, True, False))
sim = Sim(mesh, name='relax')
sim.driver.set_tols(rtol=1e-10, atol=1e-14)
sim.driver.alpha = 0.5
sim.driver.gamma = 2.211e5
sim.Ms = 8.6e5
sim.do_precession = False
sim.set_m((0,0,1))
# sim.set_m(np.load('m0.npy'))
A = 1.3e-11
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag(pbc_2d=True)
sim.add(demag)
field=demag.compute_field()
print(field)
np.save('m0.npy', sim.spin)
def test_zeeman_energy():
mu0 = 4 * np.pi * 1e-7
# A system of 8 cells ( not using nm units)
mesh = CuboidMesh(dx=2, dy=2, dz=2,
nx=2, ny=2, nz=2
)
sim = Sim(mesh)
Ms = 1e5
sim.set_Ms(Ms)
sim.set_m((0, 0, 1))
H = 0.1 / mu0
zeeman = Zeeman((0, 0, H))
sim.add(zeeman)
field = zeeman.compute_field()
zf = sim.get_interaction('Zeeman')
# -> ->
# Expected energy: Int ( -mu0 M * H ) dV
# Since we have 8 cells with the same M, we just sum their contrib
exp_energy = 8 * (-mu0 * H * Ms * mesh.dx * mesh.dy * mesh.dz)
assert np.abs(zf.compute_energy() - exp_energy) < 1e-10
def setup_domain_wall_cobalt(node_count=NODE_COUNT, A=A_Co, Ms=Ms_Co, K1=K1_Co, length=LENGTH, do_precession=True, unit_length=UNIT_LENGTH):
a = length / node_count # cell size
mesh = CuboidMesh(dx=a, dy=a, dz=a, nx=node_count, ny=1, nz=1, unit_length=unit_length)
sim = Sim(mesh, "dw_cobalt")
sim.Ms = Ms
sim.set_m(lambda r: initial_m(r, length))
sim.do_precession = do_precession
sim.add(UniformExchange(A))
sim.add(UniaxialAnisotropy(K1, (0, 0, 1)))
sim.pins = lambda r: 1 if (r[0] < a or r[0] > LENGTH - a) else 0
return sim
def test_sim_init_m_fun():
mesh = CuboidMesh(nx=3, ny=4, nz=5)
sim = Sim(mesh)
sim.set_m(init_m, normalise=False)
print sim.spin.reshape(-1, 3).shape
print sim.mesh.index(1, 2, 3)
assert(sim.spin_at(1, 2, 3)[0] == 1)
assert(sim.spin_at(1, 2, 3)[1] == 2)
assert(sim.spin_at(1, 2, 3)[2] == 3)
def elongated_part_sim():
sim = Sim(mesh)
sim.Ms = lambda r: cylinder(r, centre, 8)
sim.add(UniformExchange(A=A))
sim.add(UniaxialAnisotropy(Kx, axis=(0, 1, 0))) # Anisotropy along y
sim.add(Demag())
return sim
def test_init():
"""
This tests (mx, my, mx) for the first 2 spins
"""
mesh = CuboidMesh(nx=100, ny=1, nz=1)
sim = Sim(mesh)
sim.set_m(init_m)
expected = np.array([0, 0, 1,
0, np.sin(0.1), np.cos(0.1)])
assert max(abs(sim.spin[:6] - expected)) < 1e-15
def test_with_oommf_spatial_Ms(A=1e-11):
def spatial_Ms(pos):
x, y = pos[0], pos[1]
if x**2 + y**2 < 5**2:
return 2e4
else:
return 0
init_m0 = (
r'return [list [expr {sin($x * 1e9) + $y * 1e9 + $z * 2.3e9}] ' +
r' [expr {cos($x * 1e9) + $y * 1e9 + $z * 1.3e9}] ' + r'0 ' + r'] ')
init_Ms = """
if { ($x * $x + $y * $y) < 5e-9 * 5e-9 } {
return 2e4
} else {
return 0
}
"""
mesh = CuboidMesh(nx=12, ny=10, nz=2, dx=0.5, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = spatial_Ms
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag()
sim.add(demag)
field = exch.compute_field()
field_oommf = compute_exch_field(mesh,
init_m0=init_m0,
A=A,
spatial_Ms=init_Ms)
mx0, mx1, mx2 = compare_fields(field_oommf, field)
assert max([mx0, mx1, mx2]) < 1e-12
field = demag.compute_field()
field_oommf = compute_demag_field(mesh,
spatial_Ms=init_Ms,
init_m0=init_m0)
mx0, mx1, mx2 = compare_fields(field_oommf, field)
assert max([mx0, mx1, mx2]) < 1e-11
def test_zeeman():
mesh = CuboidMesh(nx=5, ny=2, nz=1)
sim = Sim(mesh)
sim.set_m((1, 0, 0))
zeeman = Zeeman(varying_field)
sim.add(zeeman)
field = zeeman.compute_field()
assert field[6] == 1.2 * (2 + 0.5)
assert field[7] == 2.3 * 0.5
def run(integrator, jacobian):
name = "sim_" + integrator
if integrator == "sundials":
name += "_J1" if jacobian else "_J0"
sim = Sim(mesh, name, integrator, use_jac=jacobian)
sim.Ms = 0.86e6
sim.driver.alpha = 0.5
sim.set_m((1, 0, 1))
sim.add(UniformExchange(A=13e-12))
sim.add(Demag())
ts = np.linspace(0, 3e-10, 61)
for t in ts:
sim.run_until(t)
def test_sim_single_spin(do_plot=False):
mesh = CuboidMesh(nx=1, ny=1, nz=1)
sim = Sim(mesh, name='spin')
alpha = 0.1
gamma = 2.21e5
sim.alpha = alpha
sim.driver.gamma = gamma
sim.mu_s = 1.0
sim.set_m((1, 0, 0))
H0 = 1e5
sim.add(Zeeman((0, 0, H0)))
ts = np.linspace(0, 1e-9, 101)
mx = []
my = []
mz = []
real_ts = []
for t in ts:
sim.driver.run_until(t)
real_ts.append(sim.driver.t)
print(sim.driver.t, abs(sim.spin_length()[0] - 1))
mx.append(sim.spin[0])
my.append(sim.spin[1])
mz.append(sim.spin[2])
mz = np.array(mz)
# print mz
a_mx, a_my, a_mz = single_spin(alpha, gamma, H0, ts)
print(sim.driver.stat())
if do_plot:
ts_ns = np.array(real_ts) * 1e9
plt.plot(ts_ns, mx, ".", label="mx", color='DarkGreen')
plt.plot(ts_ns, my, ".", label="my", color='darkslateblue')
plt.plot(ts_ns, mz, ".", label="mz", color='m')
plt.plot(ts_ns, a_mx, "--", label="analytical", color='b')
plt.plot(ts_ns, a_my, "--", color='b')
plt.plot(ts_ns, a_mz, "--", color='b')
plt.xlabel("time (ns)")
plt.ylabel("m")
plt.title("integrating a macrospin")
plt.legend()
plt.savefig("single_spin.pdf")
print(("Max Deviation = {0}".format(
np.max(np.abs(mz - a_mz)))))
assert np.max(np.abs(mz - a_mz)) < 5e-7
def elongated_part_sim():
sim = Sim(mesh)
sim.Ms = lambda r: cylinder(r, centre, 8)
sim.add(UniformExchange(A=A))
sim.add(UniaxialAnisotropy(Kx, axis=(0, 1, 0))) # Anisotropy along y
sim.add(Demag())
return sim
def test_sim_pin():
mesh = CuboidMesh(nx=3, ny=2, nz=1)
sim = Sim(mesh)
sim.set_m((0, 0.8, 0.6))
sim.alpha = 0.1
sim.gamma = 1.0
sim.pins = pin_fun
anis = UniaxialAnisotropy(Ku=1, axis=[0, 0, 1], name='Dx')
sim.add(anis)
sim.run_until(1.0)
print sim.spin
assert sim.spin[0] == 0
assert sim.spin[2] != 0
def create_simulation(mesh):
sim = Sim(mesh)
sim.Ms = 8.6e5
sim.set_m((1, 0, 0))
sim.add(UniformExchange(A=1.3e-11))
# sim.add(Demag())
#sim.add(UniaxialAnisotropy(Kx, (1, 0, 0), name='Kx'))
anis = UniaxialAnisotropy(1e5, axis=(1, 0, 0))
sim.add(anis)
return sim
def relax_neb(k, maxst, simname, init_im, interp, save_every=10000):
"""
Execute a simulation with the NEB function of the FIDIMAG code, for an
elongated particle (long cylinder)
The simulations are made for a specific spring constant 'k' (a float),
number of images 'init_im', interpolations between images 'interp'
(an array) and a maximum of 'maxst' steps.
'simname' is the name of the simulation, to distinguish the
output files.
--> vtks and npys are saved in files starting with the 'simname' string
"""
# Prepare simulation
# We define the cylinder with the Magnetisation function
sim = Sim(mesh)
sim.Ms = two_part
#sim.add(UniformExchange(A=A))
# Uniaxial anisotropy along x-axis
sim.add(UniaxialAnisotropy(Kx, axis=(1, 0, 0)))
# Define many initial states close to one extreme. We want to check
# if the images in the last step, are placed mostly in equally positions
init_images = init_im
# Number of images between each state specified before (here we need only
# two, one for the states between the initial and intermediate state
# and another one for the images between the intermediate and final
# states). Thus, the number of interpolations must always be
# equal to 'the number of initial states specified', minus one.
interpolations = interp
neb = NEB_Sundials(sim,
init_images,
interpolations=interpolations,
spring=k,
name=simname)
neb.relax(max_steps=maxst,
save_vtk_steps=save_every,
save_npy_steps=save_every,
stopping_dmdt=1e-2)
def test_with_oommf_spatial_Ms(A=1e-11):
def spatial_Ms(pos):
x, y = pos[0], pos[1]
if x ** 2 + y ** 2 < 5 ** 2:
return 2e4
else:
return 0
init_m0 = (r'return [list [expr {sin($x * 1e9) + $y * 1e9 + $z * 2.3e9}] '
+ r' [expr {cos($x * 1e9) + $y * 1e9 + $z * 1.3e9}] '
+ r'0 '
+ r'] ')
init_Ms = """
if { ($x * $x + $y * $y) < 5e-9 * 5e-9 } {
return 2e4
} else {
return 0
}
"""
mesh = CuboidMesh(nx=12, ny=10, nz=2, dx=0.5, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = spatial_Ms
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag()
sim.add(demag)
field = exch.compute_field()
field_oommf = compute_exch_field(
mesh, init_m0=init_m0, A=A, spatial_Ms=init_Ms)
mx0, mx1, mx2 = compare_fields(field_oommf, field)
assert max([mx0, mx1, mx2]) < 1e-12
field = demag.compute_field()
field_oommf = compute_demag_field(
mesh, spatial_Ms=init_Ms, init_m0=init_m0)
mx0, mx1, mx2 = compare_fields(field_oommf, field)
assert max([mx0, mx1, mx2]) < 1e-11
def test_dmi_field_oommf(D=4.1e-3, Ms=2.6e5):
mesh = CuboidMesh(nx=10, ny=3, nz=2, dx=0.5, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
dmi = DMI(D=D, type='interfacial')
sim.add(dmi)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
field = dmi.compute_field()
init_m0 = """
return [list [expr {sin($x*1e9)+$y*1e9+$z*2.3e9}] [expr {cos($x*1e9)+$y*1e9+$z*1.3e9}] 0]
"""
# TODO: check the sign of DMI in OOMMF.
#field_oommf = compute_dmi_field(mesh, Ms=Ms, init_m0=init_m0, D=-D)
omf_file = os.path.join(os.path.dirname(os.path.abspath(__file__)),'omfs','test_dmi_field_oommf.ohf')
ovf = OMF2(omf_file)
field_oommf = ovf.get_all_mags()
mx0, mx1, mx2 = compare_fields(field_oommf, field)
assert max([mx0, mx1, mx2]) < 1e-12
def test_exch_field_oommf(A=1e-11, Ms=2.6e5):
mesh = CuboidMesh(nx=10, ny=3, nz=2, dx=0.5, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
exch = UniformExchange(A=A)
sim.add(exch)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
field = exch.compute_field()
init_m0 = """
return [list [expr {sin($x*1e9)+$y*1e9+$z*2.3e9}] [expr {cos($x*1e9)+$y*1e9+$z*1.3e9}] 0]
"""
omf_file = os.path.join(os.path.dirname(os.path.abspath(__file__)),
'omfs',
'test_exch_field_oommf.ohf'
)
ovf = OMF2(omf_file)
field_oommf = ovf.get_all_mags()
#field_oommf = compute_exch_field(mesh, Ms=Ms, init_m0=init_m0, A=A)
mx0, mx1, mx2 = compare_fields(field_oommf, field)
assert max([mx0, mx1, mx2]) < 1e-12
def test_exch_field_oommf(A=1e-11, Ms=2.6e5):
"""
Compare the exchange field from Fidimag with an equivalent
OOMMF simulation. OOMMF field data is taken from an OVF file.
"""
mesh = CuboidMesh(nx=10, ny=3, nz=2, dx=0.5, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
exch = UniformExchange(A=A)
sim.add(exch)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
field = exch.compute_field()
# An equivalent initial magnetisation for OOMMF
# The spatial variables are rescale since they are in nm
init_m0 = (
r'return [list [expr {sin($x * 1e9) + $y * 1e9 + $z * 2.3e9}] ' +
r' [expr {cos($x * 1e9) + $y * 1e9 + $z * 1.3e9}] ' + r'0 ' + r'] ')
field_oommf = compute_exch_field(mesh, Ms=Ms, init_m0=init_m0, A=A)
mx0, mx1, mx2 = compare_fields(field_oommf, field)
# Test if the maximum relative errors between both simulations
# is small enough, for every field component
assert max([mx0, mx1, mx2]) < 1e-12
def test_sim_single_spin(do_plot=False):
mesh = CuboidMesh(nx=80, ny=3, nz=3)
sim = Sim(mesh, name='spin', integrator='sundials_openmp')
alpha = 0.1
gamma = 2.21e5
sim.alpha = alpha
sim.driver.gamma = gamma
sim.mu_s = 1.0
sim.set_m((1, 0, 0))
H0 = 1e5
sim.add(Zeeman((0, 0, H0)))
ts = np.linspace(0, 1e-9, 101)
mx = []
my = []
mz = []
real_ts = []
for t in ts:
sim.driver.run_until(t)
real_ts.append(sim.driver.t)
print(sim.driver.t, abs(sim.spin_length()[0] - 1))
mx.append(sim.spin[0])
my.append(sim.spin[1])
mz.append(sim.spin[2])
mz = np.array(mz)
# print mz
a_mx, a_my, a_mz = single_spin(alpha, gamma, H0, ts)
print(sim.driver.stat())
if do_plot:
ts_ns = np.array(real_ts) * 1e9
plt.plot(ts_ns, mx, ".", label="mx", color='DarkGreen')
plt.plot(ts_ns, my, ".", label="my", color='darkslateblue')
plt.plot(ts_ns, mz, ".", label="mz", color='m')
plt.plot(ts_ns, a_mx, "--", label="analytical", color='b')
plt.plot(ts_ns, a_my, "--", color='b')
plt.plot(ts_ns, a_mz, "--", color='b')
plt.xlabel("time (ns)")
plt.ylabel("m")
plt.title("integrating a macrospin")
plt.legend()
plt.savefig("single_spin.pdf")
print(("Max Deviation = {0}".format(
np.max(np.abs(mz - a_mz)))))
assert np.max(np.abs(mz - a_mz)) < 5e-7
def test_dmi_field_oommf(D=4.1e-3, Ms=2.6e5):
mesh = CuboidMesh(nx=10, ny=3, nz=2, dx=0.5, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
dmi = DMI(D=D, type='interfacial')
sim.add(dmi)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
field = dmi.compute_field()
init_m0 = (
r'return [list [expr {sin($x * 1e9) + $y * 1e9 + $z * 2.3e9}] ' +
r' [expr {cos($x * 1e9) + $y * 1e9 + $z * 1.3e9}] ' + r'0 ' + r'] ')
# TODO: check the sign of DMI in OOMMF.
field_oommf = compute_dmi_field(mesh, Ms=Ms, init_m0=init_m0, D=-D)
mx0, mx1, mx2 = compare_fields(field_oommf, field)
assert max([mx0, mx1, mx2]) < 1e-12
def relax_string(maxst, simname, init_im, interp, save_every=10000):
"""
"""
# Prepare simulation
# We define the cylinder with the Magnetisation function
sim = Sim(mesh)
sim.Ms = two_part
# sim.add(UniformExchange(A=A))
# Uniaxial anisotropy along x-axis
sim.add(UniaxialAnisotropy(Kx, axis=(1, 0, 0)))
# Define many initial states close to one extreme. We want to check
# if the images in the last step, are placed mostly in equally positions
init_images = init_im
# Number of images between each state specified before (here we need only
# two, one for the states between the initial and intermediate state
# and another one for the images between the intermediate and final
# states). Thus, the number of interpolations must always be
# equal to 'the number of initial states specified', minus one.
interpolations = interp
string = StringMethod(sim,
init_images,
interpolations=interpolations,
name=simname,
integrator='verlet')
string.integrator.stepsize = 1e-4
# dt = integrator.stepsize means after every integrator step, the images
# are rescaled. We can run more integrator steps if we decrease the
# stepsize, e.g. dt=1e-3 and integrator.stepsize=1e-4
string.relax(max_iterations=maxst,
save_vtks_every=save_every,
save_npys_every=save_every,
stopping_dYdt=1e-14,
dt=1e-4)
return string
def create_simulation(mesh):
sim = Sim(mesh)
sim.Ms = 8.6e5
sim.set_m((1, 0, 0))
sim.add(UniformExchange(A=1.3e-11))
# sim.add(Demag())
#sim.add(UniaxialAnisotropy(Kx, (1, 0, 0), name='Kx'))
anis = UniaxialAnisotropy(1e5, axis=(1, 0, 0))
sim.add(anis)
return sim
def relax_system_only_exchange(mesh):
sim = Sim(mesh, name='relax_exchange_only')
sim.driver.set_tols(rtol=1e-6, atol=1e-6)
sim.driver.alpha = 0.5
sim.driver.gamma = 2.211e5
sim.Ms = 8.6e5
sim.do_precession = False
sim.set_m(init_m_BP)
A = 1.3e-11
exch = UniformExchange(A=A)
sim.add(exch)
sim.relax(dt=1e-13, stopping_dmdt=0.5, max_steps=5000,
save_m_steps=None, save_vtk_steps=50)
np.save('m0.npy', sim.spin)
def test_demag_field_oommf_large(Ms=8e5, A=1.3e-11):
mesh = CuboidMesh(nx=150, ny=50, nz=1, dx=2.5, dy=2.5, dz=3, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag()
sim.add(demag)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
demag_field = demag.compute_field()
exch_field = exch.compute_field()
#exact = demag.compute_exact()
init_m0 = """
return [list [expr {sin($x*1e9)+$y*1e9+$z*2.3e9}] [expr {cos($x*1e9)+$y*1e9+$z*1.3e9}] 0]
"""
#demag_oommf = compute_demag_field(mesh, Ms=Ms, init_m0=init_m0)
#exch_oommf = compute_exch_field(mesh, Ms=Ms, init_m0=init_m0, A=A)
omf_file = os.path.join(os.path.dirname(os.path.abspath(__file__)),'omfs','test_demag_field_oommf_large_Demag.ohf')
ovf = OMF2(omf_file)
demag_oommf = ovf.get_all_mags()
omf_file = os.path.join(os.path.dirname(os.path.abspath(__file__)),'omfs','test_demag_field_oommf_large_Exchange.ohf')
ovf = OMF2(omf_file)
exch_oommf = ovf.get_all_mags()
mx0, mx1, mx2 = compare_fields(demag_oommf, demag_field)
#print mx0, mx1, mx2
assert max([mx0,mx1,mx2])< 5e-10
mx0, mx1, mx2 = compare_fields(exch_oommf, exch_field)
#print mx0, mx1, mx2
assert max([mx0, mx1, mx2]) < 1e-11
def test_exch_field_oommf(A=1e-11, Ms=2.6e5):
"""
Compare the exchange field from Fidimag with an equivalent
OOMMF simulation. OOMMF field data is taken from an OVF file.
"""
mesh = CuboidMesh(nx=10, ny=3, nz=2, dx=0.5, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
exch = UniformExchange(A=A)
sim.add(exch)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
field = exch.compute_field()
# An equivalent initial magnetisation for OOMMF
# The spatial variables are rescale since they are in nm
init_m0 = (r'return [list [expr {sin($x * 1e9) + $y * 1e9 + $z * 2.3e9}] '
+ r' [expr {cos($x * 1e9) + $y * 1e9 + $z * 1.3e9}] '
+ r'0 '
+ r'] ')
field_oommf = compute_exch_field(mesh, Ms=Ms, init_m0=init_m0, A=A)
mx0, mx1, mx2 = compare_fields(field_oommf, field)
# Test if the maximum relative errors between both simulations
# is small enough, for every field component
assert max([mx0, mx1, mx2]) < 1e-12
def test_energy_dmi(Ms=8e5, D=1.32e-3):
mesh = CuboidMesh(nx=40, ny=50, nz=1, dx=2.5, dy=2.5, dz=3, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
dmi = DMI(D=D, type='interfacial')
#dmi = DMI(D=D, type='bulk')
sim.add(dmi)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 1)
sim.set_m(init_m)
dmi_energy = dmi.compute_energy()
# init_m0="""
# return [list [expr {sin($x*1e9)+$y*1e9+$z*2.3e9}] [expr {cos($x*1e9)+$y*1e9+$z*1.3e9}] 1]
#"""
#field_oommf = compute_dmi_field(mesh, Ms=Ms, init_m0=init_m0, D=D)
dmi_energy_oommf = -4.5665527749090378e-20
print 'dmi energy', dmi_energy
assert abs(dmi_energy - dmi_energy_oommf) / dmi_energy_oommf < 1e-15
def test_dmi_field_oommf(D=4.1e-3, Ms=2.6e5):
mesh = CuboidMesh(nx=10, ny=3, nz=2, dx=0.5, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
dmi = DMI(D=D, type='interfacial')
sim.add(dmi)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
field = dmi.compute_field()
init_m0 = (r'return [list [expr {sin($x * 1e9) + $y * 1e9 + $z * 2.3e9}] '
+ r' [expr {cos($x * 1e9) + $y * 1e9 + $z * 1.3e9}] '
+ r'0 '
+ r'] ')
# TODO: check the sign of DMI in OOMMF.
field_oommf = compute_dmi_field(mesh, Ms=Ms, init_m0=init_m0, D=-D)
mx0, mx1, mx2 = compare_fields(field_oommf, field)
assert max([mx0, mx1, mx2]) < 1e-12
def run_sim():
mesh = CuboidMesh()
sim = Sim(mesh, name='spin')
alpha = 0.1
gamma = 2.21e5
sim.alpha = alpha
sim.driver.gamma = gamma
sim.mu_s = 1.0
sim.set_m((1, 0, 0))
H0 = 1e5
sim.add(Zeeman((0, 0, H0)))
sim.driver.run_until(1e-10)
sim.driver.run_until(0.5e-10)
def test_dmi_field_oommf(D=4.1e-3, Ms=2.6e5):
mesh = CuboidMesh(nx=10, ny=3, nz=2, dx=0.5, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
dmi = DMI(D=D, dmi_type='interfacial')
sim.add(dmi)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
field = dmi.compute_field()
init_m0 = """
return [list [expr {sin($x*1e9)+$y*1e9+$z*2.3e9}] [expr {cos($x*1e9)+$y*1e9+$z*1.3e9}] 0]
"""
# TODO: check the sign of DMI in OOMMF.
#field_oommf = compute_dmi_field(mesh, Ms=Ms, init_m0=init_m0, D=-D)
omf_file = os.path.join(os.path.dirname(os.path.abspath(__file__)),'omfs','test_dmi_field_oommf.ohf')
ovf = OMF2(omf_file)
field_oommf = ovf.get_all_mags()
mx0, mx1, mx2 = compare_fields(field_oommf, field)
assert max([mx0, mx1, mx2]) < 1e-12
def test_exch_field_oommf(A=1e-11, Ms=2.6e5):
mesh = CuboidMesh(nx=10, ny=3, nz=2, dx=0.5, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
exch = UniformExchange(A=A)
sim.add(exch)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
field = exch.compute_field()
init_m0 = """
return [list [expr {sin($x*1e9)+$y*1e9+$z*2.3e9}] [expr {cos($x*1e9)+$y*1e9+$z*1.3e9}] 0]
"""
omf_file = os.path.join(os.path.dirname(os.path.abspath(__file__)),
'omfs',
'test_exch_field_oommf.ohf'
)
ovf = OMF2(omf_file)
field_oommf = ovf.get_all_mags()
#field_oommf = compute_exch_field(mesh, Ms=Ms, init_m0=init_m0, A=A)
mx0, mx1, mx2 = compare_fields(field_oommf, field)
assert max([mx0, mx1, mx2]) < 1e-12
def relax_system():
mesh = CuboidMesh(nx=1, ny=1, nz=1)
sim = Sim(mesh, name='relax')
sim.driver.set_tols(rtol=1e-10, atol=1e-10)
sim.driver.alpha = 0.5
sim.set_m((1.0, 0, 0))
sim.add(Zeeman((0, 0, 1e5)))
ts = np.linspace(0, 1e-9, 1001)
for t in ts:
sim.run_until(t)
def test_energy(Ms=8e5, A=1.3e-11, D=1.32e-3):
mesh = CuboidMesh(nx=40,
ny=50,
nz=1,
dx=2.5,
dy=2.5,
dz=3,
unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag()
sim.add(demag)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
demag_energy = demag.compute_energy()
exch_energy = exch.compute_energy()
# init_m0="""
# return [list [expr {sin($x*1e9)+$y*1e9+$z*2.3e9}] [expr {cos($x*1e9)+$y*1e9+$z*1.3e9}] 0]
#"""
#field_oommf = compute_exch_field(mesh, Ms=Ms, init_m0=init_m0, A=A)
exch_energy_oommf = 1.9885853028738599e-19
demag_energy_oommf = 5.5389695779175673e-19
dmi_energy_oommf = 2.6657360769014251e-20
print(demag_energy, exch_energy)
assert abs(exch_energy - exch_energy_oommf) / exch_energy_oommf < 3e-15
assert abs(demag_energy - demag_energy_oommf) / demag_energy_oommf < 1e-10
def test_demag_field_oommf_large(Ms=8e5, A=1.3e-11):
mesh = CuboidMesh(nx=150,
ny=50,
nz=1,
dx=2.5,
dy=2.5,
dz=3,
unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag()
sim.add(demag)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
demag_field = demag.compute_field()
exch_field = exch.compute_field()
#exact = demag.compute_exact()
init_m0 = (
r'return [list [expr {sin($x * 1e9) + $y * 1e9 + $z * 2.3e9}] ' +
r' [expr {cos($x * 1e9) + $y * 1e9 + $z * 1.3e9}] ' + r'0 ' + r'] ')
demag_oommf = compute_demag_field(mesh, Ms=Ms, init_m0=init_m0)
exch_oommf = compute_exch_field(mesh, Ms=Ms, init_m0=init_m0, A=A)
mx0, mx1, mx2 = compare_fields(demag_oommf, demag_field)
#print mx0, mx1, mx2
assert max([mx0, mx1, mx2]) < 5e-10
mx0, mx1, mx2 = compare_fields(exch_oommf, exch_field)
#print mx0, mx1, mx2
assert max([mx0, mx1, mx2]) < 1e-11
def relax_neb(k, maxst, simname, init_im, interp, save_every=10000):
"""
Execute a simulation with the NEB function of the FIDIMAG code, for a
nano disk
The simulations are made for a specific spring constant 'k' (a float),
number of images 'init_im', interpolations between images 'interp'
(an array) and a maximum of 'maxst' steps.
'simname' is the name of the simulation, to distinguish the
output files.
--> vtks and npys are saved in folders starting with the 'simname'
"""
# Prepare simulation
# We define the small cylinder with the Magnetisation function
sim = Sim(mesh)
sim.Ms = cylinder
# Energies
# Exchange
sim.add(UniformExchange(A=A))
# Bulk DMI --> This produces a Bloch DW - like skyrmion
sim.add(DMI(D=D))
# No Demag, but this could have some effect
# Demagnetization energy
# sim.add(Demag())
# Initial images (npy files or functions)
init_images = init_im
# Number of images between each state specified before (here we need only
# two, one for the states between the initial and intermediate state
# and another one for the images between the intermediate and final
# states). Thus, the number of interpolations must always be
# equal to 'the number of initial states specified', minus one.
interpolations = interp
# Initiate the NEB algorithm driver
neb = NEB_Sundials(sim,
init_images,
interpolations=interpolations,
spring=k,
name=simname)
# Start the relaxation
neb.relax(max_steps=maxst,
save_vtk_steps=save_every,
save_npy_steps=save_every,
stopping_dmdt=1)
def test_sim_pin():
mesh = CuboidMesh(nx=3, ny=2, nz=1)
sim = Sim(mesh, integrator='sundials_openmp')
sim.set_m((0, 0.8, 0.6))
sim.alpha = 0.1
sim.driver.gamma = 1.0
sim.pins = pin_fun
anis = UniaxialAnisotropy(Ku=1, axis=[0, 0, 1], name='Dx')
sim.add(anis)
sim.driver.run_until(1.0)
print(sim.spin)
assert sim.spin[0] == 0
assert sim.spin[2] != 0
def test_demag_field_oommf_large(Ms=8e5, A=1.3e-11):
mesh = CuboidMesh(nx=150, ny=50, nz=1, dx=2.5, dy=2.5, dz=3, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag()
sim.add(demag)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
demag_field = demag.compute_field()
exch_field = exch.compute_field()
#exact = demag.compute_exact()
init_m0 = """
return [list [expr {sin($x*1e9)+$y*1e9+$z*2.3e9}] [expr {cos($x*1e9)+$y*1e9+$z*1.3e9}] 0]
"""
#demag_oommf = compute_demag_field(mesh, Ms=Ms, init_m0=init_m0)
#exch_oommf = compute_exch_field(mesh, Ms=Ms, init_m0=init_m0, A=A)
omf_file = os.path.join(os.path.dirname(os.path.abspath(__file__)),'omfs','test_demag_field_oommf_large_Demag.ohf')
ovf = OMF2(omf_file)
demag_oommf = ovf.get_all_mags()
omf_file = os.path.join(os.path.dirname(os.path.abspath(__file__)),'omfs','test_demag_field_oommf_large_Exchange.ohf')
ovf = OMF2(omf_file)
exch_oommf = ovf.get_all_mags()
mx0, mx1, mx2 = compare_fields(demag_oommf, demag_field)
#print mx0, mx1, mx2
assert max([mx0,mx1,mx2])< 5e-10
mx0, mx1, mx2 = compare_fields(exch_oommf, exch_field)
#print mx0, mx1, mx2
assert max([mx0, mx1, mx2]) < 1e-11
def test_compute_field():
"""In an infinite film, we expect the demag tensor to be (0, 0, -1), and thus the
magnetisation, if aligned in 0, 0, 1 direction, to create a demag field pointing
with equal strength in the opposite direction.
"""
mesh = CuboidMesh(nx=1, ny=1, nz=1, dx=2.0, dy=2.0, dz=2.0,
unit_length=1e-9, periodicity=(True, True, False))
sim = Sim(mesh, name='relax')
sim.driver.set_tols(rtol=1e-10, atol=1e-14)
sim.alpha = 0.5
sim.gamma = 2.211e5
sim.Ms = 8.6e5
sim.do_precession = False
sim.set_m((0, 0, 1))
demag = Demag(pbc_2d=True)
sim.add(demag)
field = demag.compute_field()
print((1 + field[2] / 8.6e5))
assert abs(1 + field[2] / 8.6e5) < 1e-10
def run_sim(): mesh = CuboidMesh() sim = Sim(mesh, name='spin') alpha = 0.1 gamma = 2.21e5 sim.alpha = alpha sim.driver.gamma = gamma sim.mu_s = 1.0 sim.set_m((1, 0, 0)) H0 = 1e5 sim.add(Zeeman((0, 0, H0))) sim.driver.run_until(1e-10) sim.driver.run_until(0.5e-10)
def relax_system():
mesh = CuboidMesh(nx=1, ny=1, nz=1)
sim = Sim(mesh, name='relax')
sim.driver.set_tols(rtol=1e-10, atol=1e-10)
sim.driver.alpha = 0.5
sim.set_m((1.0, 0, 0))
sim.add(Zeeman((0, 0, 1e5)))
ts = np.linspace(0, 1e-9, 1001)
for t in ts:
sim.run_until(t)
def relax_neb(k, maxst, simname, init_im, interp, save_every=10000):
"""
Execute a simulation with the NEB function of the FIDIMAG code, for a
nano disk
The simulations are made for a specific spring constant 'k' (a float),
number of images 'init_im', interpolations between images 'interp'
(an array) and a maximum of 'maxst' steps.
'simname' is the name of the simulation, to distinguish the
output files.
--> vtks and npys are saved in folders starting with the 'simname'
"""
# Prepare simulation
# We define the small cylinder with the Magnetisation function
sim = Sim(mesh)
sim.Ms = cylinder
# Energies
# Exchange
sim.add(UniformExchange(A=A))
# Bulk DMI --> This produces a Bloch DW - like skyrmion
sim.add(DMI(D=D))
# No Demag, but this could have some effect
# Demagnetization energy
# sim.add(Demag())
# Initial images (npy files or functions)
init_images = init_im
# Number of images between each state specified before (here we need only
# two, one for the states between the initial and intermediate state
# and another one for the images between the intermediate and final
# states). Thus, the number of interpolations must always be
# equal to 'the number of initial states specified', minus one.
interpolations = interp
# Initiate the NEB algorithm driver
neb = NEB_Sundials(sim,
init_images,
interpolations=interpolations,
spring=k,
name=simname)
# Start the relaxation
neb.relax(max_steps=maxst,
save_vtk_steps=save_every,
save_npy_steps=save_every,
stopping_dmdt=1)
def test_sim_init_m_fun():
mesh = CuboidMesh(nx=3, ny=4, nz=5)
sim = Sim(mesh)
sim.set_m(init_m, normalise=False)
print(sim.spin.reshape(-1, 3).shape)
print(sim.mesh.index(1, 2, 3))
assert (sim.spin_at(1, 2, 3)[0] == 1)
assert (sim.spin_at(1, 2, 3)[1] == 2)
assert (sim.spin_at(1, 2, 3)[2] == 3)
def test_sim_pin():
mesh = CuboidMesh(nx=3, ny=2, nz=1)
sim = Sim(mesh, integrator='sundials_openmp')
sim.set_m((0, 0.8, 0.6))
sim.alpha = 0.1
sim.driver.gamma = 1.0
sim.pins = pin_fun
anis = UniaxialAnisotropy(Ku=1, axis=[0, 0, 1], name='Dx')
sim.add(anis)
sim.driver.run_until(1.0)
print(sim.spin)
assert sim.spin[0] == 0
assert sim.spin[2] != 0
def test_exch_1d(do_plot=False):
# Initiate the 1D mesh and magnetisation as before
mesh = CuboidMesh(nx=100, ny=1, nz=1)
sim = Sim(mesh)
sim.set_m(init_m)
# Simplify the magnetic parameters
mu0 = 4 * np.pi * 1e-7
sim.Ms = 1.0 / mu0
exch = UniformExchange(1)
sim.add(exch)
# Compute the exchange field and reshape it in order
# to leave every row as the [f_x, f_y, f_z] array
# for every spin
field = exch.compute_field()
field.shape = (-1, 3)
# We know that the field in x is always zero ( see the
# analytical calculation at the beginning)
assert max(abs(field[:, 0])) == 0
# These are the analytical values for the exchange field in y,z
# In this case, k=0.1 , then 2 * k^2 evaluates as 0.02
xs = np.linspace(0, 99, 100)
epy = -0.02 * np.sin(0.1 * xs)
epz = -0.02 * np.cos(0.1 * xs)
# Compare the analytical value
# of the y component of the exchange field, with Fidimag's
# result (second column of the reshaped field array)
# WARNING: NOTICE that we are not considering the extremes since
# there is a wrong expression in the border of the exchange field
# with NO PBCs. We must FIX this test!
assert max(abs(epy[1:-1] - field[1:-1, 1])) < 3e-5
if do_plot:
plt.plot(xs, field[:, 1], "-.", label="my", color='DarkGreen')
plt.plot(xs, field[:, 2], "-.", label="mz", color='DarkGreen')
plt.plot(xs, epy, "--", label="analytical", color='b')
plt.plot(xs, epz, "--", color='r')
plt.xlabel("xs")
plt.ylabel("field")
plt.legend()
plt.savefig("exchange_field.pdf")
def test_zeeman():
mesh = CuboidMesh(nx=5, ny=2, nz=1)
sim = Sim(mesh)
sim.set_m((1, 0, 0))
zeeman = Zeeman(varying_field)
sim.add(zeeman)
field = zeeman.compute_field()
assert field[6] == 1.2 * (2 + 0.5)
assert field[7] == 2.3 * 0.5
def test_demag_field_oommf(Ms=6e5):
mesh = CuboidMesh(nx=5, ny=2, nz=3, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
demag = Demag()
sim.add(demag)
def init_m(pos):
x = pos[0]
if x <= 2:
return (1, 0, 0)
elif x >= 4:
return (0, 0, 1)
else:
return (0, 1, 0)
sim.set_m(init_m)
field = demag.compute_field()
exact = demag.compute_exact()
init_m0 = """
if { $x <=2e-9 } {
return "1 0 0"
} elseif { $x >= 4e-9 } {
return "0 0 1"
} else {
return "0 1 0"
}
"""
field_oommf = compute_demag_field(mesh, Ms=Ms, init_m0=init_m0)
mx0, mx1, mx2 = compare_fields(field_oommf, exact)
print(mx0, mx1, mx2)
assert max([mx0, mx1, mx2]) < 2e-14
mx0, mx1, mx2 = compare_fields(field_oommf, field)
print(mx0, mx1, mx2)
assert np.max(abs(field - field_oommf)) < 2e-9
def test_demag_field_oommf_large(Ms=8e5, A=1.3e-11):
mesh = CuboidMesh(nx=150, ny=50, nz=1, dx=2.5, dy=2.5, dz=3, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag()
sim.add(demag)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
demag_field = demag.compute_field()
exch_field = exch.compute_field()
#exact = demag.compute_exact()
init_m0 = (r'return [list [expr {sin($x * 1e9) + $y * 1e9 + $z * 2.3e9}] '
+ r' [expr {cos($x * 1e9) + $y * 1e9 + $z * 1.3e9}] '
+ r'0 '
+ r'] ')
demag_oommf = compute_demag_field(mesh, Ms=Ms, init_m0=init_m0)
exch_oommf = compute_exch_field(mesh, Ms=Ms, init_m0=init_m0, A=A)
mx0, mx1, mx2 = compare_fields(demag_oommf, demag_field)
#print mx0, mx1, mx2
assert max([mx0, mx1, mx2]) < 5e-10
mx0, mx1, mx2 = compare_fields(exch_oommf, exch_field)
#print mx0, mx1, mx2
assert max([mx0, mx1, mx2]) < 1e-11
def test_energy(Ms=8e5, A=1.3e-11, D=1.32e-3):
mesh = CuboidMesh(nx=40, ny=50, nz=1, dx=2.5, dy=2.5, dz=3, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag()
sim.add(demag)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
demag_energy = demag.compute_energy()
exch_energy = exch.compute_energy()
# init_m0="""
# return [list [expr {sin($x*1e9)+$y*1e9+$z*2.3e9}] [expr {cos($x*1e9)+$y*1e9+$z*1.3e9}] 0]
#"""
#field_oommf = compute_exch_field(mesh, Ms=Ms, init_m0=init_m0, A=A)
exch_energy_oommf = 1.9885853028738599e-19
demag_energy_oommf = 5.5389695779175673e-19
dmi_energy_oommf = 2.6657360769014251e-20
print demag_energy, exch_energy
assert abs(exch_energy - exch_energy_oommf) / exch_energy_oommf < 3e-15
assert abs(demag_energy - demag_energy_oommf) / demag_energy_oommf < 1e-10
def test_demag_field_oommf(Ms=6e5):
mesh = CuboidMesh(nx=5, ny=2, nz=3, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
demag = Demag()
sim.add(demag)
def init_m(pos):
x = pos[0]
if x <= 2:
return (1, 0, 0)
elif x >= 4:
return (0, 0, 1)
else:
return (0, 1, 0)
sim.set_m(init_m)
field = demag.compute_field()
exact = demag.compute_exact()
init_m0 = """
if { $x <=2e-9 } {
return "1 0 0"
} elseif { $x >= 4e-9 } {
return "0 0 1"
} else {
return "0 1 0"
}
"""
field_oommf = compute_demag_field(mesh, Ms=Ms, init_m0=init_m0)
mx0, mx1, mx2 = compare_fields(field_oommf, exact)
print mx0, mx1, mx2
assert max([mx0, mx1, mx2]) < 2e-14
mx0, mx1, mx2 = compare_fields(field_oommf, field)
print mx0, mx1, mx2
assert np.max(abs(field - field_oommf)) < 2e-9
def test_energy_dmi(Ms=8e5, D=1.32e-3):
mesh = CuboidMesh(nx=40,
ny=50,
nz=1,
dx=2.5,
dy=2.5,
dz=3,
unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
dmi = DMI(D=D, type='interfacial')
#dmi = DMI(D=D, type='bulk')
sim.add(dmi)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 1)
sim.set_m(init_m)
dmi_energy = dmi.compute_energy()
# init_m0="""
# return [list [expr {sin($x*1e9)+$y*1e9+$z*2.3e9}] [expr {cos($x*1e9)+$y*1e9+$z*1.3e9}] 1]
#"""
#field_oommf = compute_dmi_field(mesh, Ms=Ms, init_m0=init_m0, D=D)
dmi_energy_oommf = -4.5665527749090378e-20
print('dmi energy', dmi_energy)
assert abs(dmi_energy - dmi_energy_oommf) / dmi_energy_oommf < 1e-15
dz=dz,
unit_length=1e-9,
)
else:
print 'Using Periodic Boundary Conditions!'
mesh = CuboidMesh(nx=nx,
ny=ny,
nz=nz,
dx=dx,
dy=dy,
dz=dz,
unit_length=1e-9,
pbc=(True, True, False))
# Initiate Fidimag simulation ---------------------------------------------
sim = Sim(mesh, name=args.sim_name)
# sim.driver.set_tols(rtol=1e-10, atol=1e-14)
sim.driver.alpha = args.alpha
# sim.driver.gamma = 2.211e5
if args.no_precession:
sim.do_precession = False
# Material parameters -----------------------------------------------------
sim.Ms = args.Ms
exch = UniformExchange(A=args.A)
sim.add(exch)
