change some parameters simultaneously

[alirahdarian]

I use the following code to change 5 parameters (5 inputs) in the model but it returns an error while it works when I change only two parameters. I want to know how can I change these 5 parameters simultaneously.

import liionpack as lp
import pybamm
import numpy as np
I_mag = 5.0
OCV_init = 4.0 # used for intial guess
Ri_init = 5e-2 # used for intial guess
R_busbar = 1.5e-3
R_connection = 1e-2
Np = 2
Ns = 1
Nbatt = Np * Ns
netlist = lp.setup_circuit(
Np=Np, Ns=Ns, Rb=R_busbar, Rc=R_connection, Ri=Ri_init, V=OCV_init, I=I_mag
)
#print(netlist)

experiment = pybamm.Experiment(
[
"Charge at 2 A for 30 minutes",
"Rest for 15 minutes",
"Discharge at 2 A for 30 minutes",
"Rest for 15 minutes",
],
period="10 seconds",
)
parameter_values = pybamm.ParameterValues("Chen2020")

parameter_values.update({"Negative electrode diffusivity [m2.s-1]": "[input]"})
parameter_values.update({"Positive electrode diffusivity [m2.s-1]": "[input]"})
parameter_values.update({"Maximum concentration in negative electrode [mol.m-3]": "[input]"})
parameter_values.update({"Maximum concentration in positive electrode [mol.m-3]": "[input]"})
parameter_values.update({"SEI resistivity [Ohm.m]": "[input]"})

inputs = {"Negative electrode diffusivity [m2.s-1]": [3.3e-14,3.3e-14],
"Positive electrode diffusivity [m2.s-1]": [4e-15,4e-15],
"Maximum concentration in negative electrode [mol.m-3]": [33133.0,33133.0],
"Maximum concentration in positive electrode [mol.m-3]": [63104.0,63104.0],
"SEI resistivity [Ohm.m]": [200000.0,200000]
}

SPMe = pybamm.models.full_battery_models.lithium_ion.SPMe()
output = lp.solve(
netlist=netlist,
parameter_values=parameter_values,
experiment=experiment,
inputs=inputs,
initial_soc=0.5
)

print(parameter_values)

#lp.plot_output(output)
#lp.show_plots()

[rtimms]

Can you post the error?

[alirahdarian]

this is the error:

Traceback (most recent call last):
File "/home/ali/New_folder/pack/agedcell.py", line 43, in
output = lp.solve(
File "/home/ali/.local/lib/python3.10/site-packages/liionpack/solver_utils.py", line 427, in solve
output = rm.solve(
File "/home/ali/.local/lib/python3.10/site-packages/liionpack/solvers.py", line 201, in solve
self.setup_actors(nproc, self.inputs_dict, initial_soc)
File "/home/ali/.local/lib/python3.10/site-packages/liionpack/solvers.py", line 471, in setup_actors
a.setup(
File "/home/ali/.local/lib/python3.10/site-packages/liionpack/solvers.py", line 46, in setup
_, _ = lp.update_init_conc(parameter_values, initial_soc, update=True)
File "/home/ali/.local/lib/python3.10/site-packages/liionpack/sim_utils.py", line 53, in update_init_conc
x, y = lp.get_initial_stoichiometries(SoC, param)
File "/home/ali/.local/lib/python3.10/site-packages/liionpack/sim_utils.py", line 31, in get_initial_stoichiometries
return esoh_solver.get_initial_stoichiometries(initial_soc)
File "/home/ali/.local/lib/python3.10/site-packages/pybamm/models/full_battery_models/lithium_ion/electrode_soh.py", line 691, in get_initial_stoichiometries
x_0, x_100, y_100, y_0 = self.get_min_max_stoichiometries()
File "/home/ali/.local/lib/python3.10/site-packages/pybamm/models/full_battery_models/lithium_ion/electrode_soh.py", line 759, in get_min_max_stoichiometries
Q_n = parameter_values.evaluate(param.n.Q_init)
File "/home/ali/.local/lib/python3.10/site-packages/pybamm/parameters/parameter_values.py", line 774, in evaluate
raise ValueError("symbol must evaluate to a constant scalar or array")
ValueError: symbol must evaluate to a constant scalar or array

[NicolaCourtier]

Hi @rtimms, I came across this error and believe the cause is the assumption that neither maximum concentration is an input in pybamm.ParameterValues.set_initial_stoichiometries, line 347.

I think this can be rectified by taking the value from inputs if given, instead of evaluating the entry in param.

See also set_initial_stoichiometries_half_cell, line 307.

[rtimms]

Thanks! You can actually pass inputs as a kwarg to evaluate which is what we should do here and requires no additional logic