def _setup(self, doing=None):
assert not self.initialised, \
"FDSimulation._setup has already been called"
if self.fd_mesh == None:
if doing != None:
doing = " " + doing
raise NmagUserError("You should define a mesh before%s!" % doing)
if len(self.materials) < 1:
raise NmagUserError("You should specify at least one material!")
elif len(self.materials) > 1:
self._fd_na("multi-material")
mat = self.materials[0]
Ms = self.units.of(mat.Ms, compatible_with=SI('A/m'))
A = self.units.of(mat.exchange_coupling, compatible_with=SI('J/m'))
gamma = self.units.of(mat.llg_gamma_G, compatible_with=SI('m/s A'))
alpha = self.units.of(mat.llg_damping, compatible_with=SI(1))
Hext = array([0.0, 0.0, 0.0])
Hext = Hext/MU_ZERO
self.zeeman = Zeemanfield(self.fd_mesh, Hext)
timer1.start('exchange init')
exchange = Exchangefield(self.fd_mesh, Ms, A)
timer1.stop('exchange init')
field_dict = {'H_ext':self.zeeman, 'H_exch':exchange}
timer1.start('demag init')
if self.do_demag:
demag = Demagfield(self.fd_mesh, init_random=False,
expansion="opt")
field_dict['H_demag'] = demag
self.field_array = FieldArray(field_dict)
timer1.stop('demag init')
self.fd_model = \
self.model_cls(self.fd_mesh, self.field_array,
Ms, gamma, alpha,
precession_enabled=mat.do_precession)
self.integrator = Integrator(self.fd_model, self.ts_rel_tol,
self.ts_abs_tol, self.ts_tstep0,
method="rk", order=2)
self.initialised = True
class FDSimulation(SimulationCore):
def __init__(self, name=None, do_demag=True,model="basic"):
SimulationCore.__init__(self, name=name, do_demag=do_demag,
id="FD Simulation class")
self.initialised = False
self.field_array = None
if self._restarting:
raise NotImplementedError('Restarting capabilities are not '
'implemented by the FD code, yet!')
# These are our default simulation units.
self.units = nsim.su_units.SimulationUnits({'A': 1.0, 'kg': 1.0,
'm': 1.0, 's': 1.0,
'cd': 1.0, 'K': 1.0,
'mol': 1.0})
# The FD mesh
self.fd_mesh = None
self.zeeman = None
self.ts_rel_tol = 1e-0
self.ts_abs_tol = 1e-0
self.ts_tstep0 = 1e-15
self.integrator = None
if model == "basic":
self.model_cls = BasicMicromagneticModel
else:
raise RuntimeError("unknown finite difference model type '%s'" % model)
self.stopping_dm_dt = self.units.of(1.0*degrees_per_ns)
def _fd_na(self, reason):
"""Called internally to raise error messages which are raised
frequently"""
msgs = {
"multi-material": "The finite difference version of Nmag does "
"support multiple materials, yet. You should "
"define and use just one MagMaterial!"
}
try:
msg = msgs[reason]
except:
msg = "Unknown error!"
raise NotImplementedError(msg)
def _setup(self, doing=None):
assert not self.initialised, \
"FDSimulation._setup has already been called"
if self.fd_mesh == None:
if doing != None:
doing = " " + doing
raise NmagUserError("You should define a mesh before%s!" % doing)
if len(self.materials) < 1:
raise NmagUserError("You should specify at least one material!")
elif len(self.materials) > 1:
self._fd_na("multi-material")
mat = self.materials[0]
Ms = self.units.of(mat.Ms, compatible_with=SI('A/m'))
A = self.units.of(mat.exchange_coupling, compatible_with=SI('J/m'))
gamma = self.units.of(mat.llg_gamma_G, compatible_with=SI('m/s A'))
alpha = self.units.of(mat.llg_damping, compatible_with=SI(1))
Hext = array([0.0, 0.0, 0.0])
Hext = Hext/MU_ZERO
self.zeeman = Zeemanfield(self.fd_mesh, Hext)
timer1.start('exchange init')
exchange = Exchangefield(self.fd_mesh, Ms, A)
timer1.stop('exchange init')
field_dict = {'H_ext':self.zeeman, 'H_exch':exchange}
timer1.start('demag init')
if self.do_demag:
demag = Demagfield(self.fd_mesh, init_random=False,
expansion="opt")
field_dict['H_demag'] = demag
self.field_array = FieldArray(field_dict)
timer1.stop('demag init')
self.fd_model = \
self.model_cls(self.fd_mesh, self.field_array,
Ms, gamma, alpha,
precession_enabled=mat.do_precession)
self.integrator = Integrator(self.fd_model, self.ts_rel_tol,
self.ts_abs_tol, self.ts_tstep0,
method="rk", order=2)
self.initialised = True
def _setup_if_needed(self, doing=None):
if self.initialised:
return
self._setup(doing=doing)
def set_params(self, stopping_dm_dt=None,
ts_rel_tol=None, ts_abs_tol=None):
if stopping_dm_dt != None:
self.stopping_dm_dt = self.units.of(stopping_dm_dt,
compatible_with=SI('1/s'))
reset_tols = False
if ts_rel_tol != None:
self.ts_rel_tol = ts_rel_tol
reset_tols = True
if ts_abs_tol != None:
self.ts_abs_tol = ts_abs_tol
reset_tols = True
if reset_tols and self.integrator != None:
raise NotImplementedError("Tolerances cannot be set after the "
"integrator has been created. Try to "
"call set_params before create_mesh.")
def reinitialise(self, initial_time=None):
pass
def set_m(self, values, subfieldname=None):
print "FIXME: set_m, set_H_ext etc are not fully implemented, yet!"
if subfieldname != None:
self._fd_na("multi-material")
self._setup_if_needed("setting the magnetisation")
factor = self.fd_model.Ms
if not type(values) is FunctionType:
try:
values, u = nsim.map_terminals.SI_vector(values)
factor *= self.units.of(u, compatible_with=SI(1))
except:
pass
M0 = self.fd_mesh.create_vectorfield(values,'magnetic')
M0.shape = self.fd_mesh.get_vectorfield_flat_shape()
norm_to(self.fd_mesh, M0, factor)
M0 = M0.reshape(-1)
self.integrator.set_initial_values(self.fd_model.create_dof_field_M0(M0), 0.0)
def set_H_ext(self, values, unit=None):
v, u = nsim.map_terminals.SI_vector(values)
factor = self.units.of(u, compatible_with=SI('A/m'))
v_su = [vi*factor for vi in v]
self._setup_if_needed('setting the external field')
self.zeeman.set_field(v_su)
def set_pinning(self, values):
print "set_pinning not fully implemented, yet!"
def create_mesh(self, cell_nums, cell_sizes, materials,
regions=None, origin=(0, 0, 0)):
print "FIXME: create_mesh: boundary not included and not conforming " \
"to the interface specification: see SimulationCore class!"
cell_nums_su = [int(self.units.of(ni, compatible_with=SI(1)))
for ni in cell_nums]
cell_sizes_su = [self.units.of(si, compatible_with=SI('m'))
for si in cell_sizes]
origin_su = [self.units.of(si, compatible_with=SI('m'))
for si in origin]
self.fd_mesh = Mesh(cells=cell_nums_su, cell_sizes=cell_sizes_su,regions=regions,origin=origin_su)
if type(materials) == list:
self.materials = materials
else:
self.materials = [materials]
self._setup_if_needed()
create_mesh.__doc__ = SimulationCore.create_mesh.__doc__
def is_integration_converged(self):
return self.fd_model.get_max_dmdt() < self.stopping_dm_dt
def advance_time(self, target_time, max_it=-1):
if not self.initialised:
self._setup(doing="calling advance_time")
time_su = self.units.of(target_time, compatible_with=SI('s'))
num_steps_0 = self.integrator.used_steps
time_0 = self.integrator.t
self.integrator.integrate(time_su, max_it, stop_test=self.is_integration_converged)
delta_steps = self.integrator.used_steps - num_steps_0
delta_time = self.integrator.t - time_0
time_su2si = self.units.conversion_factor_of(SI("s"))
delta_time_si = time_su2si*delta_time
self.clock['time'] += delta_time_si
self.clock['stage_time'] += delta_time_si
self.clock['step'] += delta_steps
self.clock['stage_step'] += delta_steps
self.clock['convergence'] = self.integrator.converged
return self.clock['time']
def get_subfield_average(self, field_name, subfield_name=None):
material = self.materials[0]
if subfield_name != None and subfield_name != material.name:
self._fd_na("multi-material")
if field_name == 'm':
Ms = self.units.of(material.Ms)
return list(average(self.get_M_field_flat())/Ms)
elif field_name == 'M':
return list(average((self.get_M_field_flat()))*SI('A/m'))
elif field_name in ['H_ext', 'H_exch', 'H_demag']:
try:
H, E, H_avg = \
self.field_array.calculate_field(self.get_M_field_flat(), 0.0, field_name,
True, True)
return list(H_avg*SI('A/m'))
except:
return None
else:
return None
def load_m_from_file(self, filename, format=None):
print "FIXME: debug load_m_from_file"
if format == None:
extension = filename.split(os.extsep)[-1].lower()
format = extension
if not format in ['omf', 'ovf']:
# report a warning, not an error: we do not want the user to find
# that the simulation stopped just because the format was not the
# right one (remember one may save at the end of the simulation)
print ("FIXME: MAKE ME A LOG: WARNING: format not supported. "
"Using OMF format to save the field.")
data, X = omf.load_omf(filename)
self.set_m(data)
def save_m_to_file(self, filename, format=None):
# print "FIXME: save_m_to_file: Add a LOG!!!"
if format == None:
extension = filename.split(os.extsep)[-1].lower()
format = extension
if not format in ['omf', 'ovf']:
# report a warning, not an error: we do not want the user to find
# that the simulation stopped just because the format was not the
# right one (remember one may save at the end of the simulation)
print ("FIXME: MAKE ME A LOG: WARNING: format not supported. "
"Using OMF format to save the field.")
header_dict = omf.new_header()
nx, ny, nz = self.fd_mesh.cells
sx, sy, sz = self.fd_mesh.cellsizes
ox, oy, oz = self.fd_mesh.origin
data_to_set = \
[('xnodes', nx), ('ynodes', ny), ('znodes', nz),
('xmin', ox), ('ymin', oy), ('zmin', oz),
('xmax', ox+nx*sx), ('ymax', oy+ny*sy), ('zmax', oz+nz*sz),
('xstepsize', sx), ('ystepsize', sy), ('zstepsize', sz),
('xbase', 0.5*sx), ('ybase', 0.5*sy), ('zbase', 0.5*sz)]
omf.add_header_data(header_dict,
[('Segment', 0), ('Header', 0)],
data_to_set)
omf.write_omf(filename, self.get_M_field_flat(), header_dict=header_dict)
save_m_to_file.__doc__ = SimulationCore.save_m_to_file.__doc__
def save_data(self, fields=None, avoid_same_step=False):
SimulationCore.save_data(self, fields, avoid_same_step)
if fields != None:
if 'm' in fields or 'all' in fields:
self.clock['id'] += 1
filename = 'm-%012d.omf' % self.id
self.save_m_to_file(filename)
save_data.__doc__ = SimulationCore.save_data.__doc__
def get_M_field_flat(self):
return self.integrator.dof.M_field_flat