def setup_module(module=None):
# define the mesh
x_max = 20e-9 # m
simplexes = 10
mesh = IntervalMesh(simplexes, 0, x_max)
def m_gen(coords):
x = coords[0]
mx = min(1.0, 2.0 * x / x_max - 1.0)
my = np.sqrt(1.0 - mx**2)
mz = 0.0
return np.array([mx, my, mz])
Ms = 0.86e6
A = 1.3e-11
global sim
sim = Sim(mesh, Ms)
sim.alpha = 0.2
sim.set_m(m_gen)
sim.pins = [0, 10]
exchange = Exchange(A)
sim.add(exchange)
# Save H_exc and m at t0 for comparison with nmag
global H_exc_t0, m_t0
H_exc_t0 = exchange.compute_field()
m_t0 = sim.m
t = 0
t1 = 5e-10
dt = 1e-11
# s
av_f = open(os.path.join(MODULE_DIR, "averages.txt"), "w")
tn_f = open(os.path.join(MODULE_DIR, "third_node.txt"), "w")
global averages
averages = []
global third_node
third_node = []
while t <= t1:
mx, my, mz = sim.m_average
averages.append([t, mx, my, mz])
av_f.write(
str(t) + " " + str(mx) + " " + str(my) + " " + str(mz) + "\n")
mx, my, mz = h.components(sim.m)
m2x, m2y, m2z = mx[2], my[2], mz[2]
third_node.append([t, m2x, m2y, m2z])
tn_f.write(
str(t) + " " + str(m2x) + " " + str(m2y) + " " + str(m2z) + "\n")
t += dt
sim.run_until(t)
av_f.close()
tn_f.close()
def animation():
global it
while True:
u, v, w = helpers.components(Ms[it])
q.mlab_source.set(u=u, v=v, w=w, scalars=w)
it += 1
if it == len(Ms):
print "End of data."
break
yield
def setup_module(module=None):
x_max = 100e-9 # m
simplexes = 50
mesh = dolfin.IntervalMesh(simplexes, 0, x_max)
def m_gen(coords):
x = coords[0]
mx = min(1.0, x / x_max)
mz = 0.1
my = np.sqrt(1.0 - (0.99 * mx**2 + mz**2))
return np.array([mx, my, mz])
K1 = 520e3 # J/m^3
Ms = 0.86e6
sim = Sim(mesh, Ms)
sim.alpha = 0.2
sim.set_m(m_gen)
anis = UniaxialAnisotropy(K1, (0, 0, 1))
sim.add(anis)
# Save H_anis and m at t0 for comparison with nmag
global H_anis_t0, m_t0
H_anis_t0 = anis.compute_field()
m_t0 = sim.m
av_f = open(os.path.join(MODULE_DIR, "averages.txt"), "w")
tn_f = open(os.path.join(MODULE_DIR, "third_node.txt"), "w")
t = 0
t_max = 3e-10
dt = 5e-12
# s
while t <= t_max:
mx, my, mz = sim.m_average
averages.append([t, mx, my, mz])
av_f.write(
str(t) + " " + str(mx) + " " + str(my) + " " + str(mz) + "\n")
mx, my, mz = h.components(sim.m)
m2x, m2y, m2z = mx[2], my[2], mz[2]
third_node.append([t, m2x, m2y, m2z])
tn_f.write(
str(t) + " " + str(m2x) + " " + str(m2y) + " " + str(m2z) + "\n")
t += dt
sim.run_until(t)
av_f.close()
tn_f.close()
def test_method_of_computing_the_average_matters():
length = 20e-9 # m
simplices = 10
mesh = df.IntervalMesh(simplices, 0, length)
S1 = df.FunctionSpace(mesh, "Lagrange", 1)
S3 = df.VectorFunctionSpace(mesh, "Lagrange", 1, dim=3)
llg = LLG(S1, S3)
llg.set_m((
'(2*x[0]-L)/L',
'sqrt(1 - ((2*x[0]-L)/L)*((2*x[0]-L)/L))',
'0'), L=length)
average1 = llg.m_average
average2 = np.mean(components(llg.m_numpy), axis=1)
diff = np.abs(average1 - average2)
assert diff.max() > 5e-2
import numpy
import finmag.util.helpers as helpers
from mayavi import mlab
"""
Visualise the final configuration of the magnetisation.
"""
x = numpy.genfromtxt("1d_coord.txt")
y = numpy.zeros(len(x))
z = numpy.zeros(len(x))
Ms = numpy.genfromtxt("1d_M.txt")
Mx, My, Mz = helpers.components(Ms[-1])
figure = mlab.figure(bgcolor=(0,0,0), fgcolor=(1,1,1))
q = mlab.quiver3d(x, y, z, Mx, My, Mz, figure=figure)
q.scene.z_plus_view()
mlab.axes(figure=figure)
mlab.show()
import numpy
import finmag.util.helpers as helpers
from mayavi import mlab
"""
Visualise the evolution of the vector field M over time.
"""
x = numpy.genfromtxt("1d_coord.txt")
y = numpy.zeros(len(x))
z = numpy.zeros(len(x))
Ms = numpy.genfromtxt("1d_M.txt")
u, v, w = helpers.components(Ms[0])
figure = mlab.figure(bgcolor=(0,0,0), fgcolor=(1,1,1))
q = mlab.quiver3d(x, y, z, u, v, w, figure=figure)
q.scene.z_plus_view()
mlab.axes(figure=figure)
it = 0
@mlab.animate(delay=1000)
def animation():
global it
while True:
u, v, w = helpers.components(Ms[it])
q.mlab_source.set(u=u, v=v, w=w, scalars=w)
it += 1
if it == len(Ms):
print "End of data."
import numpy
import pylab
from finmag.util.helpers import norm, angle, components, \
vectors, rows_to_columns
# Load the data which dolfin has created and odeint has integrated.
Ms = numpy.genfromtxt("1d_M.txt")
# Each entry in ys is M for a particular moment in time.
# Each M is all the x-values of M on the mesh, followed by the y and z-values.
"""
The time series of the average value of M across the mesh.
"""
ts = numpy.genfromtxt("1d_times.txt")
averages = rows_to_columns(numpy.array([components(M).mean(1) for M in Ms]))
pylab.plot(ts, averages[0], ":", label="Mx")
pylab.plot(ts, averages[1], label="My")
pylab.plot(ts, averages[2], "-.", label="Mz")
pylab.legend()
pylab.title("dolfin - average magnetisation over time, without pinning")
pylab.xlabel("time [s]")
pylab.ylabel("magnetisation [A/m]")
pylab.show()