Dear all, I'm trying to solve a nonlinear problem on a very big mesh using newton solver. These are the lines of my code: problem = MyNonlinearProblem(L,a,bc) solver = NewtonSolver() solver.parameters["linear_solver"] = "lu" solver.parameters["convergence_criterion"] = "incremental" solver.parameters["relative_tolerance"] = 1e-6
I encountered this error: UMFPACK V5.4.0 (May 20, 2009): ERROR: out of memory Traceback (most recent call last): File "CH_BC_Tdip.py", line 170, in solver.solve(problem, u.vector()) RuntimeError: *** ------------------------------------------------------------------------- *** DOLFIN encountered an error. If you are not able to resolve this issue *** using the information listed below, you can ask for help at ------------------------------ *** [email protected] ------------------------------ *** Remember to include the error message listed below and, if possible, *** include a *minimal* running example to reproduce the error. ------------------------------ *** ------------------------------------------------------------------------- *** Error: Unable to successfully call PETSc function 'KSPSolve'. *** Reason: PETSc error code is: 76. *** Where: This error was encountered inside /build/buildd/dolfin-1.4.0+dfsg/dolfin/la/PETScLUSolver.cpp. *** Process: unknown How can I fix the problem? I have found out that I should switch to mumps as linear solver.. but I prefer to use LU. Is there a way to save memory? Is it related to the 4GB limit of UMFPACK? I'm new at dolfin and I don't know how to solve my model .. Thanks Cristina
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