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_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.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 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.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))
# 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_system(mesh):
sim = Sim(mesh, name='relax')
sim.driver.set_tols(rtol=1e-10, atol=1e-10)
sim.driver.alpha = 0.1
sim.driver.gamma = 2.211e5
sim.Ms = spatial_Ms
print(sim.Ms)
sim.set_m(init_m)
A = 1.3e-11
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag()
sim.add(demag)
dmi = DMI(D=4e-3)
sim.add(dmi)
dmi2 = DMI(D=2e-3, dmi_type="interfacial")
sim.add(dmi2)
anis = UniaxialAnisotropy(-3e4, axis=(0, 0, 1))
sim.add(anis)
sim.relax(dt=1e-13,
stopping_dmdt=5e4,
max_steps=5000,
save_m_steps=100,
save_vtk_steps=50)
#np.save('m0.npy', sim.spin)
fd = demag.compute_field(sim.spin)
fe = exch.compute_field(sim.spin)
fdmi = dmi.compute_field(sim.spin)
fdmi2 = dmi2.compute_field(sim.spin)
fanis = anis.compute_field(sim.spin)
np.savetxt(
"test_fields.txt",
np.transpose([
np.concatenate((sim.Ms, sim.Ms, sim.Ms, [0.0])),
np.concatenate((sim.spin, [100])),
np.concatenate((fd, [demag.compute_energy()])),
np.concatenate((fe, [exch.compute_energy()])),
np.concatenate((fdmi, [dmi.compute_energy()])),
np.concatenate((fdmi2, [dmi2.compute_energy()])),
np.concatenate((fanis, [anis.compute_energy()]))
]),
header=
"Generated by Fidimag. Size=20x5x3, 2.5nm x 2.5nm x 3nm, Ms=8.0e5A/m, A=1.3e-11 J/m,"
+
" D=4e-3 J/m^2, D_int=2e-3 J/m^2, Ku=-3e4 J/m^3 axis=(0,0,1).\n Ms "
+ "".ljust(20) + " m0 " + "".ljust(20) + "demag" + "".ljust(20) +
"exch" + "".ljust(22) + "dmi" + "".ljust(22) + "dmi_interfacial" +
"".ljust(22) + "anis")
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 * $y) < 5e-9 * 5e-9 } {
return 2e4
} else {
return 0
}
"""
mesh = CuboidMesh(nx=12, ny=10, nz=2, dx=0.5, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = spatial_Ms
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag()
sim.add(demag)
field = exch.compute_field()
field_oommf = compute_exch_field(mesh,
init_m0=init_m0,
A=A,
spatial_Ms=init_Ms)
mx0, mx1, mx2 = compare_fields(field_oommf, field)
assert max([mx0, mx1, mx2]) < 1e-12
field = demag.compute_field()
field_oommf = compute_demag_field(mesh,
spatial_Ms=init_Ms,
init_m0=init_m0)
mx0, mx1, mx2 = compare_fields(field_oommf, field)
assert max([mx0, mx1, mx2]) < 1e-11
def test_with_oommf_spatial_Ms(A=1e-11):
def spatial_Ms(pos):
x, y = pos[0], pos[1]
if x ** 2 + y ** 2 < 5 ** 2:
return 2e4
else:
return 0
init_m0 = (r'return [list [expr {sin($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 relax_system(mesh):
sim = Sim(mesh, name='relax')
sim.driver.set_tols(rtol=1e-10, atol=1e-10)
sim.driver.alpha = 0.5
sim.driver.gamma = 2.211e5
sim.Ms = 8.0e5
sim.do_precession = False
sim.set_m((1, 0.25, 0.1))
# sim.set_m(np.load('m0.npy'))
A = 1.3e-11
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag()
sim.add(demag)
sim.relax(dt=1e-13,
stopping_dmdt=0.01,
max_steps=5000,
save_m_steps=100,
save_vtk_steps=50)
np.save('m0.npy', sim.spin)
def apply_field1(mesh):
sim = Sim(mesh, name='dyn')
sim.driver.set_tols(rtol=1e-10, atol=1e-10)
sim.driver.alpha = 0.02
sim.driver.gamma = 2.211e5
sim.Ms = 8.0e5
sim.set_m(np.load('m0.npy'))
A = 1.3e-11
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag()
sim.add(demag)
mT = 0.001 / mu0
print("Applied field = {}".format(mT))
zeeman = Zeeman([-24.6 * mT, 4.3 * mT, 0], name='H')
sim.add(zeeman, save_field=True)
ts = np.linspace(0, 1e-9, 201)
for t in ts:
sim.driver.run_until(t)
print('sim t=%g' % t)
def relax_system(mesh):
sim = Sim(mesh, chi=1e-3, name='relax', driver='llbar_full')
sim.set_tols(rtol=1e-7, atol=1e-7)
sim.Ms = 8.0e5
sim.alpha = 0.1
sim.beta = 0
sim.gamma = 2.211e5
sim.set_m((1, 0.25, 0.1))
# sim.set_m(np.load('m0.npy'))
A = 1.3e-11
exch = UniformExchange(A=A)
sim.add(exch)
mT = 795.7747154594767
zeeman = Zeeman([-100 * mT, 4.3 * mT, 0], name='H')
sim.add(zeeman, save_field=True)
demag = Demag()
sim.add(demag)
ONE_DEGREE_PER_NS = 17453292.52
sim.relax(dt=1e-12,
stopping_dmdt=0.01,
max_steps=5000,
save_m_steps=100,
save_vtk_steps=50)
np.save('m0.npy', sim.spin)
def relax_system(mesh):
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 = spatial_Ms
sim.driver.do_precession = False
sim.set_m(init_m)
# 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)
mT = 795.7747154594767
ONE_DEGREE_PER_NS = 17453292.52
sim.relax(dt=1e-13,
stopping_dmdt=0.01,
max_steps=5000,
save_m_steps=100,
save_vtk_steps=50)
np.save('m0.npy', sim.spin)
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 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+$z*1.3e9}] 0]
"""
#demag_oommf = compute_demag_field(mesh, Ms=Ms, init_m0=init_m0)
#exch_oommf = compute_exch_field(mesh, Ms=Ms, init_m0=init_m0, A=A)
omf_file = os.path.join(os.path.dirname(os.path.abspath(__file__)),'omfs','test_demag_field_oommf_large_Demag.ohf')
ovf = OMF2(omf_file)
demag_oommf = ovf.get_all_mags()
omf_file = os.path.join(os.path.dirname(os.path.abspath(__file__)),'omfs','test_demag_field_oommf_large_Exchange.ohf')
ovf = OMF2(omf_file)
exch_oommf = ovf.get_all_mags()
mx0, mx1, mx2 = compare_fields(demag_oommf, demag_field)
#print mx0, mx1, mx2
assert max([mx0,mx1,mx2])< 5e-10
mx0, mx1, mx2 = compare_fields(exch_oommf, exch_field)
#print mx0, mx1, mx2
assert max([mx0, mx1, mx2]) < 1e-11
def test_demag_field_oommf_large(Ms=8e5, A=1.3e-11):
mesh = CuboidMesh(nx=150, ny=50, nz=1, dx=2.5, dy=2.5, dz=3, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag()
sim.add(demag)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
demag_field = demag.compute_field()
exch_field = exch.compute_field()
#exact = demag.compute_exact()
init_m0 = """
return [list [expr {sin($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 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_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(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 { $x >= 4e-9 } {
return "0 0 1"
} else {
return "0 1 0"
}
"""
field_oommf = compute_demag_field(mesh, Ms=Ms, init_m0=init_m0)
mx0, mx1, mx2 = compare_fields(field_oommf, exact)
print(mx0, mx1, mx2)
assert max([mx0, mx1, mx2]) < 2e-14
mx0, mx1, mx2 = compare_fields(field_oommf, field)
print(mx0, mx1, mx2)
assert np.max(abs(field - field_oommf)) < 2e-9
def test_energy(Ms=8e5, A=1.3e-11, D=1.32e-3):
mesh = CuboidMesh(nx=40,
ny=50,
nz=1,
dx=2.5,
dy=2.5,
dz=3,
unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag()
sim.add(demag)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
demag_energy = demag.compute_energy()
exch_energy = exch.compute_energy()
# init_m0="""
# return [list [expr {sin($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 + $z * 1.3e9}] ' + r'0 ' + r'] ')
demag_oommf = compute_demag_field(mesh, Ms=Ms, init_m0=init_m0)
exch_oommf = compute_exch_field(mesh, Ms=Ms, init_m0=init_m0, A=A)
mx0, mx1, mx2 = compare_fields(demag_oommf, demag_field)
#print mx0, mx1, mx2
assert max([mx0, mx1, mx2]) < 5e-10
mx0, mx1, mx2 = compare_fields(exch_oommf, exch_field)
#print mx0, mx1, mx2
assert max([mx0, mx1, mx2]) < 1e-11
def test_demag_field_oommf_large(Ms=8e5, A=1.3e-11):
mesh = CuboidMesh(nx=150, ny=50, nz=1, dx=2.5, dy=2.5, dz=3, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag()
sim.add(demag)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
demag_field = demag.compute_field()
exch_field = exch.compute_field()
#exact = demag.compute_exact()
init_m0 = (r'return [list [expr {sin($x * 1e9) + $y * 1e9 + $z * 2.3e9}] '
+ r' [expr {cos($x * 1e9) + $y * 1e9 + $z * 1.3e9}] '
+ r'0 '
+ r'] ')
demag_oommf = compute_demag_field(mesh, Ms=Ms, init_m0=init_m0)
exch_oommf = compute_exch_field(mesh, Ms=Ms, init_m0=init_m0, A=A)
mx0, mx1, mx2 = compare_fields(demag_oommf, demag_field)
#print mx0, mx1, mx2
assert max([mx0, mx1, mx2]) < 5e-10
mx0, mx1, mx2 = compare_fields(exch_oommf, exch_field)
#print mx0, mx1, mx2
assert max([mx0, mx1, mx2]) < 1e-11
def setup_simulation(mesh,
m0,
simulation_name,
integrator="sundials",
use_jac=False):
sim = Sim(mesh, name=simulation_name, integrator=integrator, use_jac)
sim.set_m(m0)
sim.Ms = Ms
sim.alpha = alpha
sim.gamma = gamma
sim.add(UniformExchange(A))
sim.add(Demag())
return sim
def test_energy(Ms=8e5, A=1.3e-11, D=1.32e-3):
mesh = CuboidMesh(nx=40, ny=50, nz=1, dx=2.5, dy=2.5, dz=3, unit_length=1e-9)
sim = Sim(mesh)
sim.Ms = Ms
exch = UniformExchange(A=A)
sim.add(exch)
demag = Demag()
sim.add(demag)
def init_m(pos):
x, y, z = pos
return (np.sin(x) + y + 2.3 * z, np.cos(x) + y + 1.3 * z, 0)
sim.set_m(init_m)
demag_energy = demag.compute_energy()
exch_energy = exch.compute_energy()
# init_m0="""
# return [list [expr {sin($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 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_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 excite_system(mesh):
sim = Sim(mesh, name='dyn')
sim.driver.set_tols(rtol=1e-10, atol=1e-14)
sim.driver.alpha = 0.01
sim.driver.gamma = 2.211e5
sim.Ms = spatial_Ms
# sim.set_m(init_m)
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)
mT = 795.7747154594767
sigma = 0.08e-9
def gaussian_fun(t):
return np.exp(-0.5 * (t / sigma)**2)
zeeman = TimeZeeman((80 * mT, 0, 0), time_fun=gaussian_fun, name='hx')
#zeeman = Zeeman((100*mT,0,0), name='hx')
sim.add(zeeman, save_field=True)
ts = np.linspace(0, 1e-9, 501)
for t in ts:
print('time', t)
print('length:', sim.spin_length()[0:200])
sim.run_until(t)
sim.save_vtk()
sim.add(exch)
dmi = DMI(D=(args.D * 1e-3), type='interfacial')
sim.add(dmi)
if args.B:
zeeman = Zeeman((0, 0, args.B / mu0))
sim.add(zeeman, save_field=True)
if args.k_u:
# Uniaxial anisotropy along + z-axis
sim.add(UniaxialAnisotropy(args.k_u, axis=(0, 0, 1)))
if args.Demag:
print 'Using Demag!'
sim.add(Demag())
# -------------------------------------------------------------------------
# Load magnetisation profile ---------------------------------------------
# Change the skyrmion initial configuration according to the
# chirality of the system (give by the DMI constant)
if args.initial_state_skyrmion_down:
if args.D > 0:
sim.set_m(lambda x: generate_skyrmion_down(x, -1))
else:
sim.set_m(lambda x: generate_skyrmion_down(x, 1))
elif args.initial_state_skyrmion_up:
if args.D > 0:
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 = """
return [list [expr {sin($x*1e9)+$y*1e9+$z*2.3e9}] [expr {cos($x*1e9)+$y*1e9+$z*1.3e9}] 0]
"""
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
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)
field = exch.compute_field()
#field_oommf = compute_exch_field(mesh, init_m0=init_m0, A=A, spatial_Ms=init_Ms)
omf_file = os.path.join(os.path.dirname(os.path.abspath(__file__)),'omfs','test_with_oommf_spatial_Ms_Exchange.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
field = demag.compute_field()
#field_oommf = compute_demag_field(mesh, spatial_Ms=init_Ms, init_m0=init_m0)
omf_file = os.path.join(os.path.dirname(os.path.abspath(__file__)),'omfs','test_with_oommf_spatial_Ms_Demag.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-11
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 = """
return [list [expr {sin($x*1e9)+$y*1e9+$z*2.3e9}] [expr {cos($x*1e9)+$y*1e9+$z*1.3e9}] 0]
"""
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
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)
field = exch.compute_field()
#field_oommf = compute_exch_field(mesh, init_m0=init_m0, A=A, spatial_Ms=init_Ms)
omf_file = os.path.join(os.path.dirname(os.path.abspath(__file__)),'omfs','test_with_oommf_spatial_Ms_Exchange.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
field = demag.compute_field()
#field_oommf = compute_demag_field(mesh, spatial_Ms=init_Ms, init_m0=init_m0)
omf_file = os.path.join(os.path.dirname(os.path.abspath(__file__)),'omfs','test_with_oommf_spatial_Ms_Demag.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-11