Timestep 80 / 1000 (simulation time = 8) cells = 396 dofs = 1189 Refinement Started Refinement Finished Grid written to results/grid_80.gnuplot Refinement step done in 0.000000[s] step made in 42.0398 seconds

Saving results... Time since start = 0

Timestep 81 / 1000 (simulation time = 8.1) cells = 517 dofs = 1552

Exception:

An error occurred in line <1345> of file </usr/include/deal.II/lac/solver_cg.h> in function void dealii::SolverCG::solve(const MatrixType&, VectorType&, const VectorType&, const PreconditionerType&) [with MatrixType = dealii::SparseMatrix; PreconditionerType = dealii::PreconditionIdentity; VectorType = dealii::Vector] The violated condition was: solver_state == SolverControl::success Additional information: Iterative method reported convergence failure in step 5000. The residual in the last step was 0.00370817.

This error message can indicate that you have simply not allowed a
sufficiently large number of iterations for your iterative solver to
converge. This often happens when you increase the size of your
problem. In such cases, the last residual will likely still be very
small, and you can make the error go away by increasing the allowed
number of iterations when setting up the SolverControl object that
determines the maximal number of iterations you allow.

The other situation where this error may occur is when your matrix is
not invertible (e.g., your matrix has a null-space), or if you try to
apply the wrong solver to a matrix (e.g., using CG for a matrix that
is not symmetric or not positive definite). In these cases, the
residual in the last iteration is likely going to be large.

Stacktrace:

#0 ./nufi_poisson: void dealii::SolverCG<dealii::Vector >::solve<dealii::SparseMatrix, dealii::PreconditionIdentity>(dealii::SparseMatrix const&, dealii::Vector&, dealii::Vector const&, dealii::PreconditionIdentity const&) #1 ./nufi_poisson: PoissonProblem<1>::solve() #2 ./nufi_poisson: PoissonProblem<1>::solve_step() #3 ./nufi_poisson: NuFISolver::run() #4 ./nufi_poisson: main