I tried to run the FitzHugh-Nagumo model which is hardcoded in the heart component. The test I wrote does run without any errors with a different cell model, however if I use the FitzHugh-Nagumo model I get the following error:
Error: Test failed:
Chaste error: ./global/src/parallel/PetscException.cpp:159: DIVERGED_NANORINF in function 'User provided function' on line 1128 of file ./linalg/src/LinearSystem.cpp
My guess is that the error is somehow caused by problems with the linear solver from Petsc. Thus I played around with some KSP settings - but to no avail. In the internet it was suggested for similar problems to use a direct solver. Is it possible to do so in Chaste and if so, how can I do it?
Surprisingly this error does not occur if I use very small stimuli well below the threshold.
Is the FitzHugh-Nagumo model still maintained in the current version of Chaste and is part of the tests?
Edit: With my original parameters also the LuoRudy1 model showed either this error or threw the "!std::isnan(i_ionic)-exception". That's why I switched back to the standard parameters. Here the LuoRudy1 model and the Bueno model (which also worked before) are running fine. However, the FitzHugh-Nagumo model still has the same problems.
The code that is creating this error can be found here: https://etherpad.gwdg.de/p/csQYkPSDEhCQM5w
Thanks a lot!