def eval_f(self, part, t):
"""
Routine to compute the E and B fields (named f for consistency with the original PEPC version)
Args:
part (dtype_u): the particles
t (float): current time (not used here)
Returns:
dtype_f: Fields for the particles (internal and external)
"""
N = self.params.nparts
Emat = np.diag([1, 1, -2])
f = fields(self.params.nparts)
f.elec.values = self.get_interactions(part)
for n in range(N):
f.elec.values[3 * n:3 * n + 3] += self.params.omega_E ** 2 / (part.q[n] / part.m[n]) * \
np.dot(Emat, part.pos.values[3 * n:3 * n + 3])
f.magn.values[3 * n:3 * n +
3] = self.params.omega_B * np.array([0, 0, 1])
return f
def restrict(self, F):
"""
Dummy restriction routine
Args:
F: the fine level data
"""
if isinstance(F, particles):
G = particles(F)
elif isinstance(F, fields):
G = fields(F)
else:
raise TransferError("Unknown type of fine data, got %s" % type(F))
return G
def prolong(self, G):
"""
Dummy prolongation routine
Args:
G: the coarse level data
"""
if isinstance(G, particles):
F = particles(G)
elif isinstance(G, fields):
F = fields(G)
else:
raise TransferError("Unknown type of coarse data, got %s" %
type(G))
return F
def eval_f(self, part, t):
"""
Routine to compute the electric and magnetic fields
Args:
t: current time
part: the current particle
Returns:
E and B field for the particle (external only)
"""
f = fields((3, self.nparts))
R = np.linalg.norm(part.pos.values[:, 0], 2)
f.elec.values[0, 0] = self.params.a0 / (R**3) * part.pos.values[0, 0]
f.elec.values[1, 0] = self.params.a0 / (R**3) * part.pos.values[1, 0]
f.elec.values[2, 0] = 0
f.magn.values[0, 0] = 0
f.magn.values[1, 0] = 0
f.magn.values[2, 0] = R
return f