[docs]
class PushVinEfield(Propagator):
r"""Push the velocities according to
.. math::
\frac{\text{d} \mathbf{v}_p}{\text{d} t} = \frac{1}{\varepsilon}\mathbf{E}(\mathbf{x}_p) \,,
where :math:`\varepsilon \in \mathbb R` is a constant. In logical coordinates, given by :math:`\mathbf x = F(\boldsymbol \eta)`:
.. math::
\frac{\text{d} \mathbf{v}_p}{\text{d} t} = \frac{1}{\varepsilon}DF^{-\top}\hat{\mathbf E}^1(\boldsymbol \eta_p) \,,
which is solved analytically. :math:`\mathbf E` can optionally be defined
through a potential, :math:`\mathbf E = - \nabla \phi`.
"""
[docs]
class Variables:
"""Container for variables advanced by :class:`PushVinEfield`.
Attributes
----------
var : PICVariable or SPHVariable
Particle variable whose velocities are advanced.
"""
def __init__(self):
self._var: PICVariable | SPHVariable = None
@property
def var(self) -> PICVariable | SPHVariable:
return self._var
@var.setter
def var(self, new):
assert isinstance(new, PICVariable | SPHVariable)
assert new.space in ("Particles6D", "DeltaFParticles6D", "ParticlesSPH")
self._var = new
def __init__(
self,
phi: FEECVariable | Callable = None,
e_field: FEECVariable | tuple[Callable] = None,
):
"""
Parameters
----------
phi : FEECVariable or Callable, default=None
Electrostatic potential from which the electric field is built as
``-grad(phi)``. If provided, it overrides ``e_field``.
Accepted forms are an ``H1`` FEEC variable or a callable projected
via ``L2Projector``.
e_field : FEECVariable or tuple of Callables, default=None
Electric field used directly in velocity pushing.
Accepted forms are an ``Hcurl`` FEEC variable or a tuple of
callables to be projected. Ignored when ``phi`` is set.
"""
self.variables = self.Variables()
if isinstance(phi, FEECVariable):
assert phi.space == "H1"
if isinstance(e_field, FEECVariable):
assert e_field.space == "Hcurl"
self.phi = phi
self.e_field = e_field
[docs]
@dataclass(repr=False)
class Options(OptionsBase):
"""Configuration options for :class:`PushVinEfield`."""
def __post_init__(self):
pass
@property
def options(self) -> Options:
if not hasattr(self, "_options"):
self._options = self.Options()
return self._options
@options.setter
def options(self, new):
assert isinstance(new, self.Options)
self._options = new
logger.info(f"\nNew options for propagator '{self.__class__.__name__}':\n{self._options}")
@profile
def allocate(self):
# scaling factor
self._epsilon = self.variables.var.species.equation_params.epsilon
self._e_field = None
if self.e_field is not None:
if isinstance(self.e_field, tuple[Callable]):
self._e_field = self.derham.P1(self.e_field)
else:
self._e_field = self.e_field.spline.vector
if self.phi is not None:
if isinstance(self.phi, Callable):
_phi = self.derham.P0(self.phi)
else:
_phi = self.phi.spline.vector
self._e_field = self.derham.grad.dot(_phi)
self._e_field.update_ghost_regions() # very important, we will move it inside grad
self._e_field *= -1.0
if self._e_field is not None:
# instantiate Pusher
args_kernel = (
self.derham.args_derham,
self._e_field[0]._data,
self._e_field[1]._data,
self._e_field[2]._data,
1.0 / self._epsilon,
)
self._pusher = Pusher(
self.variables.var.particles,
Pyccelkernel(pusher_kernels.push_v_with_efield),
args_kernel,
self.domain.args_domain,
alpha_in_kernel=1.0,
)
def __call__(self, dt):
if self._e_field is not None:
self._pusher(dt)
