Hey Shawn,thank you for reporting this. It helps to relax the threshold for the reduction of the residual that the linear solver is required to achieve. I attach a corresponding input file, where the parameter is adjusted in line 31.
To me, the default threshold of 1e-12 seems to be very small. We will discuss whether the default value should be adjusted.
Kind regards Bernd On Fri, 23 Mar 2012 12:36:05 -0700 (PDT) Shawn Zhang <[email protected]> wrote:
Dear All,I ran into an issue of 1p model not converging. After a series of tests, I trace it to this canonical situation, For standard test/boxmodels/1p problem, if I increase the 2D grid resolution from 10x10 to 100x100, the solver will not converge, with the following error reported.This error, however, will go away if I reduce the perm difference between lens and exterior from 2 order of magnitude into 1 order of magnitude. This makes me speculate that the error is related to sharp gradient at lens/exterior interface caused by the heterogeneity at high resolution.I think the reproducer on standard test makes it likely a serious problem, though I will be very happily corrected.Truly appreciate your quick attention. Best, -Shawnroot@szdebian:/home/szhang/dumux/dumux-2.1.0/test/boxmodels/1p# ./test_1p -parameterFile test_1p.input Welcome aboard DuMuX airlines. Please fasten your seatbelts! Emergency exits are near the time integration.Initializing problem '1ptest' Writing result file for "1ptest" Newton iteration 1 done, relative error = 0.666666 Newton iteration 2 done, relative error = 5.45083e-06Solve: M deltax^k = rNewton: Caught exception: "NumericalProblem [newtonSolveLinear:../../../dumux/nonlinear/newtoncontroller.hh:398]: Linear solver did not converge" Newton solver did not converge with dt=1 seconds. Retrying with time step of 0.5 secondsNewton iteration 1 done, relative error = 0.666666 Newton iteration 2 done, relative error = 5.45083e-06Solve: M deltax^k = rNewton: Caught exception: "NumericalProblem [newtonSolveLinear:../../../dumux/nonlinear/newtoncontroller.hh:398]: Linear solver did not converge"....Newton solver did not converge with dt=0.0078125 seconds. Retrying with time step of 0.00390625 secondsNewton iteration 1 done, relative error = 0.666666 Newton iteration 2 done, relative error = 5.45083e-06Solve: M deltax^k = rNewton: Caught exception: "NumericalProblem [newtonSolveLinear:../../../dumux/nonlinear/newtoncontroller.hh:398]: Linear solver did not converge" Newton solver did not converge with dt=0.00390625 seconds. Retrying with time step of 0.00195312 secondsNewton iteration 1 done, relative error = 0.666666 Newton iteration 2 done, relative error = 5.45083e-06Solve: M deltax^k = rNewton: Caught exception: "NumericalProblem [newtonSolveLinear:../../../dumux/nonlinear/newtoncontroller.hh:398]: Linear solver did not converge" Newton solver did not converge with dt=0.00195312 seconds. Retrying with time step of 0.000976562 seconds Dune reported error: Dune::MathError [timeIntegration:../../../dumux/boxmodels/common/boxproblem.hh:485]: Newton solver didn't converge after 10 time-step divisions. dt=0.000976562
___________________________________________________________Bernd Flemisch phone: +49 711 685 69162 IWS, Universitaet Stuttgart fax: +49 711 685 67020 Pfaffenwaldring 61 email: [email protected] D-70569 Stuttgart url: www.hydrosys.uni-stuttgart.de
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test_1p.input
Description: Binary data
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