Change _libwarpx.py functions to LibWarpX class methods (#2696)

* Initial attempt at moving function into LibWarpX

* Bugfix - undefined structs in get_particle_theta

This is untested, identified by IDE/visual inspection only

* Unify newlines

* Delete libwarpx.clight (duplicated picmi.py)

See picmi.constants.c

* Change function descriptive comment to docstring

Also remove extra newline in __init__ beginning.

* Replace pywarpx/_libwarpx calls appropriately

* Fix atexit register of finalize function

* Reorder WarpX.py imports for pre-commit

* Use picmi.Simulation.extension = libwarpx alias

This will hopefully preempt user script changes if we restructure things
to allow multiple WarpX runs to be done within a single Python script.

* Fix libwarpx ref in WarpX.getProbLo/getProbHi

* Update get_particle_boundary_buffer doc reference

1 files changed, 3 insertions, 4 deletions

diff --git a/Examples/Tests/ParticleDataPython/PICMI_inputs_prev_pos_2d.py b/Examples/Tests/ParticleDataPython/PICMI_inputs_prev_pos_2d.py
index d71aa3fea..9cfe669ce 100755
--- a/Examples/Tests/ParticleDataPython/PICMI_inputs_prev_pos_2d.py
+++ b/Examples/Tests/ParticleDataPython/PICMI_inputs_prev_pos_2d.py
@@ -3,7 +3,6 @@
 # --- Input file to test the saving of old particle positions
 
 import numpy as np
-import pywarpx
 from pywarpx import picmi
 
 constants = picmi.constants
@@ -110,10 +109,10 @@ sim.step(max_steps - 1)
 # exist
 ##########################
 
-assert (pywarpx.get_particle_comp_index('electrons', 'prev_x') > 0)
-assert (pywarpx.get_particle_comp_index('electrons', 'prev_z') > 0)
+assert (sim.extension.get_particle_comp_index('electrons', 'prev_x') > 0)
+assert (sim.extension.get_particle_comp_index('electrons', 'prev_z') > 0)
 
-prev_z_vals = pywarpx.get_particle_arrays(
+prev_z_vals = sim.extension.get_particle_arrays(
     'electrons', 'prev_z', 0
 )
 for z_vals in prev_z_vals: