Hello, We are trying to solve a 2-layer Quasi-Geostrophic model to determine a steady linear solution, basically building on a demo that we already wrote. When we try running it we get the following error, copied below. It seems to have a problem with the nonlinear solver, even though we are solving a linear problem. Can anyone give us some advice on how we might be able to fix this? Code is attached in case you wanted to see the details. Cheers, Francis (firedrake) fpoulin@domlt32:~/Dropbox/Research_Keegan/Code$ python test.py Traceback (most recent call last): File "test.py", line 91, in <module> soln0 = steadylinearQG2d(Ztrial, Ztest, Gwinds, bcs) File "test.py", line 46, in steadylinearQG2d linear_solver.solve() File "/home/fpoulin/software/firedrake/src/firedrake/firedrake/variational_solver.py", line 223, in solve solving_utils.check_snes_convergence(self.snes) File "/home/fpoulin/software/firedrake/src/firedrake/firedrake/solving_utils.py", line 233, in check_snes_convergence %s""" % (snes.getIterationNumber(), msg)) firedrake.exceptions.ConvergenceError: Nonlinear solve failed to converge after 0 nonlinear iterations. Reason: Inner linear solve failed to converge after 0 iterations with reason: unknown reason (petsc4py enum incomplete?), try with -snes_converged_reason and -ksp_converged_reason ------------------ Francis Poulin Associate Professor Department of Applied Mathematics University of Waterloo email: fpoulin@uwaterloo.ca Web: https://uwaterloo.ca/poulin-research-group/ Telephone: +1 519 888 4567 x32637