PICMI Standard example does not work

[szabo137]

Problem

Seems like there is an incompatibility with picmistandard, if one tries to run the intro example for picmi from the picongpu docs.

minimal example

Running a test-file with

from picongpu import picmi

boundary_conditions = ["periodic", "periodic", "periodic"]
grid = picmi.Cartesian3DGrid(
    # note: [x] * 3 == [x, x, x]
    number_of_cells=[192] * 3,
    lower_bound=[0, 0, 0],
    upper_bound=[0.0111152256] * 3,

    # delta {x, y, z} is computed implicitly

    # lower & upper boundary conditions must be equal
    lower_boundary_conditions=boundary_conditions,
    upper_boundary_conditions=boundary_conditions,
)
solver = picmi.ElectromagneticSolver(method="Yee",grid=grid)

sim = picmi.Simulation(
    time_step_size=9.65531e-14,
    max_steps=1024,
    solver=solver,
)

throws

Traceback (most recent call last):
  File "/Users/uwe/Work/tutorials/picmi/picongpu/lib/python/test2.py", line 18, in <module>
    sim = picmi.Simulation(
  File "/Users/uwe/.pyenv/versions/venv_picmi/lib/python3.10/site-packages/typeguard/__init__.py", line 1033, in wrapper
    retval = func(*args, **kwargs)
  File "/Users/uwe/Work/tutorials/picmi/picongpu/lib/python/picongpu/picmi/simulation.py", line 115, in __init__
    self.__yee_compute_cfl_or_delta_t()
  File "/Users/uwe/.pyenv/versions/venv_picmi/lib/python3.10/site-packages/typeguard/__init__.py", line 1033, in wrapper
    retval = func(*args, **kwargs)
  File "/Users/uwe/Work/tutorials/picmi/picongpu/lib/python/picongpu/picmi/simulation.py", line 61, in __yee_compute_cfl_or_delta_t
    delta_x = (self.solver.grid.xmax - self.solver.grid.xmin) \
AttributeError: 'Cartesian3DGrid' object has no attribute 'xmax'

A bit deeper investigation shows, there seems to be an api change between picmistandard==0.0.19 and picmipstandard==0.0.20 with (at least)

grid.xmin = grid.lower_bound[0]
grid.ymin = grid.lower_bound[1]
grid.zmin = grid.lower_bound[2]

grid.xmax = grid.upper_bound[0]
grid.ymax = grid.upper_bound[1]
grid.zmax = grid.upper_bound[2]

grid.bc_xmin = grid.lower_boundary_conditions[0]
grid.bc_ymin = grid.lower_boundary_conditions[1]
grid.bc_zmin = grid.lower_boundary_conditions[2]

grid.bc_xmax = grid.upper_boundary_conditions[0]
grid.bc_ymax = grid.upper_boundary_conditions[1]
grid.bc_zmax = grid.upper_boundary_conditions[2]

grid.nx = grid.number_of_cells[0]
grid.ny = grid.number_of_cells[1]
grid.nz = grid.number_of_cells[2]

I tested the minimal example above with picmistandard==0.0.19 and it works as intended.

System specs

python version: 3.10.6
picongpu branch: dev
pip list output:

attrs           22.1.0
chevron         0.14.0
contourpy       1.0.6
cycler          0.11.0
fonttools       4.38.0
h5py            3.7.0
imageio         2.22.4
jsonschema      4.17.1
kiwisolver      1.4.4
matplotlib      3.6.2
mpmath          1.2.1
numpy           1.23.5
openPMD-api     0.14.5.post1
packaging       21.3
pandas          1.5.2
picmistandard   0.0.22
Pillow          9.3.0
Pint            0.20.1
pip             22.3.1
pyparsing       3.0.9
pyrsistent      0.19.2
python-dateutil 2.8.2
pytz            2022.6
scipy           1.9.3
setuptools      63.2.0
six             1.16.0
sympy           1.11.1
typeguard       2.13.3

Suggested solution

From the top of my head, there are three solutions conceivable

• Pinning the version of picmistandard to 0.0.19, but new features would be missing
• Open a PR for picmistandard to include the back-compatibility
• update the lib/python/picongpu in order to use the new API from picmistandard>=0.0.20

[BrianMarre]

A student I am supervising is updating the lib/python/piconpgu to the new API of the current pcimistandard==0.0.22
Seems to be mostly done, but the compiling test are not yet done, will prompt him to create a pull request once they are finished.

[BrianMarre]

I am also going to discuss the breaking changes with the PICMI-standard devs, they were not properly communicated in the changelogs.

[BrianMarre]

@szabo137 the issue can be closed, the update is complete.

[PrometheusPi]

I will reopen the issue since #4364 is not yet in the mainline dev

[BrianMarre]

@PrometheusPi ping

[PrometheusPi]

#4364 was merged