Hello,
I used dolfin.refine() to refine a 2D mesh based on some cell marker I created. However, the refined mesh seems to create some problem for the solver. I am working on a short, reproducible example code, but at this point I wanted to know more about what dolfin.refine() does to the mesh other than refinement that might lead to such issue. The solver I used is solver = PETScKrylovSolver( "cg", 'petsc_amg').
Error:
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*** Error: Unable to solve linear system using PETSc Krylov solver.
*** Reason: Solution failed to converge in 0 iterations (PETSc reason DIVERGED_NANORINF, residual norm ||r|| = 0.000000e+00).
*** Where: This error was encountered inside PETScKrylovSolver.cpp.
*** Process: 0
***
*** DOLFIN version: 2019.1.0
*** Git changeset: 15b823f2c45d3036b6af931284d0f8e3c77b6845
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