#
# (C) 2006 Dr. Thomas Fischbacher
# Exchange spring computation using nmag
#
# XXX Ad anisotropy: this is new and hot. Perhaps it would be nice to
# also provide a function to plot an energy hypersurface in 3d - so
# that we can use the very same function definition to both
# auto-generate a plot and use it in the simulation!
import nmag1 as mag, nmesh as nm, sys, math, time
import nfem # for debugging
mag.set_intensive_parameters(
["H_x", "H_y", "H_z"], # may also set T,p,E, etc.
external_magnetization=["H_x", "H_y", "H_z"])
# mag.set_default_order(1) # default anyway...
mag.set_features({
"demag": False,
"exchange": True,
"timestep": True
}) # XXX change usage!
mat_Dy = mag.MagMaterial(
"Dy",
Ms=2.5,
A=0.0, # A = exchange constant
anisotropy=(
2, lambda r: -4.0 * r[2] * r[2]
#
# (C) 2006 Dr. Thomas Fischbacher
# Exchange spring computation using nmag
#
# XXX Ad anisotropy: this is new and hot. Perhaps it would be nice to
# also provide a function to plot an energy hypersurface in 3d - so
# that we can use the very same function definition to both
# auto-generate a plot and use it in the simulation!
import nmag1 as mag, nmesh as nm, sys, math, time
import nfem # for debugging
mag.set_intensive_parameters(["H_x","H_y","H_z"], # may also set T,p,E, etc.
external_magnetization=["H_x","H_y","H_z"])
mag.set_default_order(2)
mag.set_features({"demag":False,"exchange":True,"timestep":True}) # XXX change usage!
mat_Dy = mag.MagMaterial("Dy",Ms=2.5,A=0.0, # A = exchange constant
anisotropy=(2,lambda r: -4.0*r[2]*r[2]),
extra_H="H_total_Dy(0) -= mag[0]*2.5;",
)
mat_Fe = mag.MagMaterial("Fe",Ms=1.2,A=4.0,
extra_H="""H_total_Fe(0) -= mag[0]*1.2;
if(X(0)<0.01 || X(0)>2.99) /* pin the M field at boundaries */
{
H_total_Fe(0)=0.0;
#
# (C) 2006 Dr. Thomas Fischbacher
# Relaxation of the homogeneously magnetized sphere
import nmag1 as mag, nmesh as nm, sys, math, time
import nfem # for debugging
#mag.set_intensive_parameters(["H_x","H_y","H_z"], # may also set T,p,E, etc.
# external_magnetization=["H_x","H_y","H_z"])
# ^ XXX not used yet, as we are going to use the experimental cvode integrator...
mag.set_intensive_parameters([])
# mag.set_default_order(1) # default anyway...
mag.set_features({"demag":True,"exchange":True,"timestep":True}) # XXX change usage!
mat_Py = mag.MagMaterial("Py",Ms=1.0,A=13.0, # A = exchange constant
)
mag.defregion("Py", nm.ellipsoid([3.0,3.0,3.0]), mag_mat=mat_Py)
mag.set_meshing_parameters(cache_name="exchange-spring-mesh",
bounding_box=([-4.0,-4.0,-4.0],[4.0,4.0,4.0]),
a0=1.0,
max_steps=600,
)
mag.create_mesh()
import time
# Note: we should make a habit of always starting out by defining
# the additional intensive parameters of our model.
#This adds a Zeeman field:
PermAlloy = mag.MagMaterial("Funny",
extra_H="""
h_total_Funny[0] += 0.0;
h_total_Funny[1] += 1.0;
h_total_Funny[2] += 0.0;
""")
mag.set_default_material(PermAlloy)
mag.set_intensive_parameters(["T", "p", "H_x", "H_y", "H_z"])
#mag.defregion("Ball 1",nm.ellipsoid([3.0,3.0,3.0],transform=[("shift",[-3.0,0.0,0.0])]))
print "OK 1"
sys.stdout.flush()
#mag.defregion("Ball 2",nm.ellipsoid([3.0,3.0,3.0],transform=[("shift",[3.0,0.0,0.0])]))
mag.defregion(
"Ball 2",
nm.ellipsoid([2.0, 2.0, 2.0], transform=[("shift", [3.0, 0.0, 0.0])]))
# Note: clearly, we DO need a better way to specify geometries. Ideally, I would like to be
# able to write instead:
#
import time
# Note: we should make a habit of always starting out by defining
# the additional intensive parameters of our model.
#This adds a Zeeman field:
PermAlloy=mag.MagMaterial("Funny",extra_H="""
h_total_Funny[0] += 0.0;
h_total_Funny[1] += 1.0;
h_total_Funny[2] += 0.0;
""")
mag.set_default_material(PermAlloy)
mag.set_intensive_parameters(["T","p","H_x","H_y","H_z"])
#mag.defregion("Ball 1",nm.ellipsoid([3.0,3.0,3.0],transform=[("shift",[-3.0,0.0,0.0])]))
print "OK 1"
sys.stdout.flush()
#mag.defregion("Ball 2",nm.ellipsoid([3.0,3.0,3.0],transform=[("shift",[3.0,0.0,0.0])]))
mag.defregion("Ball 2",nm.ellipsoid([2.0,2.0,2.0],transform=[("shift",[3.0,0.0,0.0])]))
# Note: clearly, we DO need a better way to specify geometries. Ideally, I would like to be
# able to write instead:
#
# mag.defregion("Ball 1",nm.shifted([-3,0,0],nm.sphere(3)))
# mag.defregion("Ball 2",nm.shifted([ 3,0,0],nm.sphere(3)))