Bessel functions as CoefficientFunctions


I want to use the bessel function from a python library (for example scipy.special) as a CoefficientFunctions.

my code:
from ngsolve import *
from scipy.special import jn #import bessel J function
uexact = jn(1,x)

I get the following error:
uexact = jn(1,x)
TypeError: ufunc ‘jv’ not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule ‘‘safe’’

Is there a way to use these functions from a python library as CoefficentFunction?

Thank you,


Hi, no you cannot use scipy functions as coefficients, but we have the ngs-special-functions addon that provides these functions:


Hi Christopher,
Thank you for your answer!
I followed the instruction to install the package on Linux and I tried to run the demo but I get an import error:

ImportError: /home/c/rzanol/.local/lib/python3.8/site-packages/ngsolve/ undefined symbol: _ZNK5ngfem19CoefficientFunction14GetDescriptionB5cxx11Ev

Do you have any idea what could be the problem?