[Bug]: IDAKLU Solver incompatible with OKane2022 NE OCP Interpolation

[tomjholland]

PyBaMM Version

24.9

Python Version

3.11

Describe the bug

Casadi error is returned when using the IDAKLU solver with the OKane2022 parameter set. Appears to be related to the interpolation of the negative electrode OCP, as it is searching for libcasadi_interpolatnt_bspline.dylib and setting the OCP to the functional form in Chen2020 eliminates the error.

This is a separate issue, but I will tag #4365 as another issue caused by the interpolation of discrete points of NE OCP in this parameter set.

Steps to Reproduce

exp = pybamm.Experiment([ "Discharge at 1C until 2.5 V"])
model = pybamm.lithium_ion.DFN()
params = pybamm.ParameterValues("OKane2022")
solver = pybamm.IDAKLUSolver()
sim = pybamm.Simulation(model, experiment=exp, parameter_values=params, solver=solver)
sim.solve()

Produces the Runtime error:

RuntimeError: .../casadi/core/casadi_os.cpp:166: Assertion "handle!=nullptr" failed:
PluginInterface::load_plugin: Cannot load shared library 'libcasadi_interpolant_bspline.dylib': 
   (
    Searched directories: 1. casadipath from GlobalOptions
                          2. CASADIPATH env var
                          3. PATH env var (Windows)
                          4. LD_LIBRARY_PATH env var (Linux)
                          5. DYLD_LIBRARY_PATH env var (osx)
    A library may be 'not found' even if the file exists:
          * library is not compatible (different compiler/bitness)
          * the dependencies are not found
   )
  Tried '' :
    Error code: dlopen(libcasadi_interpolant_bspline.dylib, 0x0005): tried: 'libcasadi_interpolant_bspline.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OSlibcasadi_interpolant_bspline.dylib' (no such file), '/Users/tom/anaconda3/envs/pybamm/lib/python3.11/site-packages/pybamm/.dylibs/libcasadi_interpolant_bspline.dylib' (no such file), '/Users/tom/anaconda3/envs/pybamm/bin/../lib/libcasadi_interpolant_bspline.dylib' (no such file), '/usr/lib/libcasadi_interpolant_bspline.dylib' (no such file, not in dyld cache), 'libcasadi_interpolant_bspline.dylib' (no such file), '/usr/local/lib/libcasadi_interpolant_bspline.dylib' (no such file), '/usr/lib/libcasadi_interpolant_bspline.dylib' (no such file, not in dyld cache)
  Tried '.' :
    Error code: dlopen(./libcasadi_interpolant_bspline.dylib, 0x0005): tried: './libcasadi_interpolant_bspline.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS./libcasadi_interpolant_bspline.dylib' (no such file), '/Users/tom/anaconda3/envs/pybamm/lib/python3.11/site-packages/pybamm/.dylibs/./libcasadi_interpolant_bspline.dylib' (no such file), '/Users/tom/anaconda3/envs/pybamm/bin/../lib/./libcasadi_interpolant_bspline.dylib' (no such file), '/usr/lib/./libcasadi_interpolant_bspline.dylib' (no such file, not in dyld cache), './libcasadi_interpolant_bspline.dylib' (no such file), '/Users/tom/Library/CloudStorage/OneDrive-ImperialCollegeLondon/PhD Workspace/11 - PyBaMM DMA Analysis/pybamm-settings/libcasadi_interpolant_bspline.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/Users/tom/Library/CloudStorage/OneDrive-ImperialCollegeLondon/PhD Workspace/11 - PyBaMM DMA Analysis/pybamm-settings/libcasadi_interpolant_bspline.dylib' (no such file), '/Users/tom/Library/CloudStorage/OneDrive-ImperialCollegeLondon/PhD Workspace/11 - PyBaMM DMA Analysis/pybamm-settings/libcasadi_interpolant_bspline.dylib' (no such file)

This can be overcome by changing the OCP function of the parameter set:

exp = pybamm.Experiment([ "Discharge at 1C until 2.5 V"])
model = pybamm.lithium_ion.DFN()
params = pybamm.ParameterValues("OKane2022")
params["Negative electrode OCP [V]"] = pybamm.ParameterValues("Chen2020")['Negative electrode OCP [V]']
solver = pybamm.IDAKLUSolver()
sim = pybamm.Simulation(model, experiment=exp, parameter_values=params, solver=solver)
sim.solve()

Relevant log output

No response

[MarcBerliner]

@tomjholland just double-checking – are you on PyBaMM v24.9 or develop? As a temporary workaround, you can change the OCP interpolant to "linear".

cc @kratman

[agriyakhetarpal]

This is the same bug as the one with the CasADi plugin system: #3783. A hacky workaround is in #4487 at the time of writing

[kratman]

For Linux and Mac this fix from #4487 can resolve this issue. The change is needed inside pybamm's main __init__.py:

# Fix Casadi import
import os
import sysconfig
if sys.platform == "win32":
    os.environ["CASADIPATH"] = os.path.join(sysconfig.get_path('purelib'), 'casadi').replace("\\", "\\\\")
else:
    os.environ["CASADIPATH"] = os.path.join(sysconfig.get_path('purelib'), 'casadi')

This does not work on Windows yet, I am working on improving the Windows build to make it work there as well.

@tomjholland For tracking issues:

• Which OS are you using?
• Are you using 24.9 installed from pip or from source?

[kratman]

I can reproduce this on MacOS with PyBaMM 24.9 on MacOS

[kratman]

@tomjholland This works on my Mac as a workaround:

import pybamm

# Fix Casadi import
import os
import sysconfig
os.environ["CASADIPATH"] = os.path.join(sysconfig.get_path('purelib'), 'casadi')

exp = pybamm.Experiment([ "Discharge at 1C until 2.5 V"])
model = pybamm.lithium_ion.DFN()
params = pybamm.ParameterValues("OKane2022")
solver = pybamm.IDAKLUSolver()
sim = pybamm.Simulation(model, experiment=exp, parameter_values=params, solver=solver)
sim.solve()

[tomjholland]

Hi @kratman, thanks for the quick response on this.

Sorry, I forgot to add this detail to the issue. I get this error from 24.9 installed from pip on MacOS and Linux. I can confirm that your workaround also works for me on my Mac.

Thanks for the help!

[kratman]

Partial fix was added to develop, it will be in the next release (hopefully in the next week or two)