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# This is a script that adds particle components at runtime,
# then performs checkpoint / restart and compares the result
# to the original simulation.
from pywarpx import picmi
import numpy as np
import sys
##########################
# physics parameters
##########################
dt = 7.5e-10
##########################
# numerics parameters
##########################
max_steps = 10
nx = 64
ny = 64
xmin = 0
xmax = 0.03
ymin = 0
ymax = 0.03
##########################
# numerics components
##########################
grid = picmi.Cartesian2DGrid(
number_of_cells = [nx, ny],
lower_bound = [xmin, ymin],
upper_bound = [xmax, ymax],
lower_boundary_conditions = ['dirichlet', 'periodic'],
upper_boundary_conditions = ['dirichlet', 'periodic'],
lower_boundary_conditions_particles = ['absorbing', 'periodic'],
upper_boundary_conditions_particles = ['absorbing', 'periodic'],
moving_window_velocity = None,
warpx_max_grid_size = 32
)
solver = picmi.ElectrostaticSolver(
grid=grid, method='Multigrid', required_precision=1e-6,
warpx_self_fields_verbosity=0
)
##########################
# physics components
##########################
electrons = picmi.Species(
particle_type='electron', name='electrons'
)
##########################
# diagnostics
##########################
field_diag = picmi.FieldDiagnostic(
name = 'diag1',
grid = grid,
period = 10,
data_list = ['phi'],
write_dir = '.',
warpx_file_prefix = f'Python_restart_runtime_components_plt'
)
checkpoint = picmi.Checkpoint(
name = 'chkpoint',
period = 5,
write_dir = '.',
warpx_file_prefix = f'Python_restart_runtime_components_chk'
)
##########################
# simulation setup
##########################
sim = picmi.Simulation(
solver = solver,
time_step_size = dt,
max_steps = max_steps,
verbose = 1
)
sim.add_species(
electrons,
layout = picmi.GriddedLayout(
n_macroparticle_per_cell=[0, 0], grid=grid
)
)
for arg in sys.argv:
if arg.startswith("amr.restart"):
restart_file_name = arg.split("=")[1]
sim.amr_restart = restart_file_name
sim.add_diagnostic(field_diag)
sim.add_diagnostic(checkpoint)
sim.initialize_inputs()
sim.initialize_warpx()
##########################
# python particle data access
##########################
from pywarpx import _libwarpx, callbacks
_libwarpx.add_real_comp('electrons', 'newPid')
def add_particles():
nps = 10
x = np.random.rand(nps) * 0.03
y = np.zeros(nps)
z = np.random.random(nps) * 0.03
ux = np.random.normal(loc=0, scale=1e3, size=nps)
uy = np.random.normal(loc=0, scale=1e3, size=nps)
uz = np.random.normal(loc=0, scale=1e3, size=nps)
w = np.ones(nps) * 2.0
newPid = 5.0
_libwarpx.add_particles(
species_name='electrons', x=x, y=y, z=z, ux=ux, uy=uy, uz=uz,
w=w, newPid=newPid
)
callbacks.installbeforestep(add_particles)
##########################
# simulation run
##########################
step_number = _libwarpx.libwarpx.warpx_getistep(0)
sim.step(max_steps - 1 - step_number)
##########################
# check that the new PIDs are properly set
##########################
assert(_libwarpx.get_particle_count('electrons') == 90)
assert (_libwarpx.get_particle_comp_index('electrons', 'w') == 0)
assert (_libwarpx.get_particle_comp_index('electrons', 'newPid') == 4)
new_pid_vals = _libwarpx.get_particle_arrays(
'electrons', 'newPid', 0
)
for vals in new_pid_vals:
assert np.allclose(vals, 5)
##########################
# take the final sim step
##########################
sim.step(1)
|
