def test_step_integrator(integrator, stepsize_reported, stepsize_internal):
ts = np.arange(interval[0], interval[1], step=stepsize_reported)
print(ts)
print(ts[1:])
ys = np.zeros(ts.shape[0])
ys[0] = y_true(ts[0]) # known initial value
integrator = StepIntegrator(ys[0],
f,
step="euler",
stepsize=stepsize_internal)
for i, t in enumerate(ts[1:]):
integrator.run_until(t)
ts[i + 1] = integrator.t
ys[i + 1] = integrator.y
assert 85 < ys[-1] < 100
return ts, ys
def set_integrator(self, integrator, use_jac):
# Integrator options --------------------------------------------------
# Here we set up the CVODE integrator from Sundials to evolve a
# specific micromagnetic equation. The equations are specified in the
# sundials_rhs function from any of the micromagnetic drivers in the
# micromagnetic folder (LLG, LLG_STT, etc.)
if integrator == "sundials" and use_jac:
self.integrator = CvodeSolver(self.spin, self.sundials_rhs,
self.sundials_jtimes)
elif integrator == "sundials_diag":
self.integrator = CvodeSolver(self.spin,
self.sundials_rhs,
linear_solver="diag")
elif integrator == "sundials":
self.integrator = CvodeSolver(self.spin, self.sundials_rhs)
elif integrator == "euler" or integrator == "rk4":
self.integrator = StepIntegrator(self.spin, self.step_rhs)
elif integrator == "scipy":
self.integrator = ScipyIntegrator(self.spin, self.step_rhs)
elif integrator == "sundials_openmp" and use_jac:
self.integrator = CvodeSolver_OpenMP(self.spin, self.sundials_rhs,
self.sundials_jtimes)
elif integrator == "sundials_diag_openmp":
self.integrator = CvodeSolver_OpenMP(self.spin,
self.sundials_rhs,
linear_solver="diag")
elif integrator == "sundials_openmp":
self.integrator = CvodeSolver_OpenMP(self.spin, self.sundials_rhs)
elif integrator == "euler_openmp" or integrator == "rk4_openmp":
self.integrator = CvodeSolver_OpenMP(self.spin, self.step_rhs,
integrator)
else:
raise NotImplemented("integrator must be sundials, euler or rk4")
def __init__(self, mesh, name='unnamed', integrator='sundials'):
"""Simulation object.
*Arguments*
name : the Simulation name (used for writing data files, for examples)
"""
self.t = 0
self.name = name
self.mesh = mesh
self.n = mesh.n
self.n_nonzero = mesh.n
self.unit_length = mesh.unit_length
self._alpha = np.zeros(self.n, dtype=np.float)
self._Ms = np.zeros(self.n, dtype=np.float)
self._Ms_inv = np.zeros(self.n, dtype=np.float)
self.spin = np.ones(3 * self.n, dtype=np.float)
self.spin_last = np.ones(3 * self.n, dtype=np.float)
self._pins = np.zeros(self.n, dtype=np.int32)
self.field = np.zeros(3 * self.n, dtype=np.float)
self.dm_dt = np.zeros(3 * self.n, dtype=np.float)
self._skx_number = np.zeros(self.n, dtype=np.float)
self.interactions = []
self.pin_fun = None
self.integrator_tolerances_set = False
self.step = 0
if integrator == "sundials":
self.integrator = SundialsIntegrator(self.spin, self.sundials_rhs)
elif integrator == "euler" or integrator == "rk4":
self.integrator = StepIntegrator(self.spin, self.step_rhs, integrator)
else:
raise NotImplemented("integrator must be sundials, euler or rk4")
self.saver = DataSaver(self, name + '.txt')
self.saver.entities['E_total'] = {
'unit': '<J>',
'get': lambda sim: sim.compute_energy(),
'header': 'E_total'}
self.saver.entities['m_error'] = {
'unit': '<>',
'get': lambda sim: sim.compute_spin_error(),
'header': 'm_error'}
self.saver.entities['skx_num'] = {
'unit': '<>',
'get': lambda sim: sim.skyrmion_number(),
'header': 'skx_num'}
self.saver.entities['rhs_evals'] = {
'unit': '<>',
'get': lambda sim: self.integrator.rhs_evals,
'header': 'rhs_evals'}
self.saver.entities['real_time'] = {
'unit': '<s>',
'get': lambda _: time.time(), # seconds since epoch
'header': 'real_time'}
self.saver.update_entity_order()
# This is for old C files codes using the xperiodic variables
self.xperiodic, self.yperiodic, self.zperiodic = mesh.periodicity
self.vtk = SaveVTK(self.mesh, name=name)
self.set_default_options()
