RuntimeError while trying to run drive cycle in experiment with initial SOC

[Mrzhang-hub]

Hi! I am trying to run a drive cycle in an experiment but it keeps failing. Part of the code as follows:

options = {"lithium plating":"irreversible","thermal": "lumped"}
model = pybamm.lithium_ion.SPMe(options=options)
param = pybamm.ParameterValues('OKane2022')
soc_init = 0.2
drive_cycle_current = pd.read_csv("StandardCycle/UDDS.csv", comment="#", header=None).to_numpy()
exp = pybamm.Experiment([("Run UDDS_A (A)")],drive_cycles={"UDDS_A": drive_cycle_current})
sim = pybamm.Simulation(model=model, parameter_values=param, experiment=exp)
sol = sim.solve(initial_soc=soc_init)

It gives the error:

RuntimeError: .../casadi/core/slice.cpp:83: Assertion "stop<=len" failed:
Slice (start=0, stop=20, step=1) out of bounds with supplied length of 1

But when I remove the lithium plating option, the code works well.

Why? Can you help me handle this? @rtimms @tinosulzer

[RuiheLi]

Hi, I think this error you showed is related to the solver, which is quite difficult to debug. PyBaMM tries to give as much information as possible such as exceptions. However, there are always some other problems out of these exceptions. That is the tricky part of simulation which I think it is quite generous. However, based on my personal experience, there are still something worth checking:

1. voltage, such as terminal voltage, negative/positive electrode potential, electrolyte potential, etc.
2. concentration, especially particle surface concentration and electrolyte concentration
3. porosity, especially negative electrode porosity

Other things to try are to reduce dt_max, try another solver, etc.. Also, I found that reducing the time to exactly when the model fails can probably give you more information. To do that, you can divide your whole experiments / cycles into smaller pieces and use the set_initial_conditions_from function in PyBaMM to run step by step.

Also, it is worth reading through the examples that PyBaMM provides here, sometimes you may find some useful scripts/functions.

I currently have not found any shortcuts in debugging or avoiding errors. Though I wish I have~ lol.