Hello, Thank you for your suggestions. In essence, what happens here is that your solver has just diverged. > This may be for three reasons: > * The matrix or right hand side already contain INF or NaN values. You > can test this by printing the norm of the matrix and rhs before you > send them to the solver. This can happen, for example, if you have > nonlinear problems where physically, the solution should be positive, > but the numerical approximation has some negative values and you > still apply functions such as sqrt or log to it when you compute > nonlinear coefficients in the matrix or rhs. > I checked by printing the norm of right hand side and it doesn't have value of INF or NaN.
> * The matrix does not satisfy the conditions that are necessary for > BiCGStab to converge. You can test this by using a different > solver instead, e.g., a direct solver. If the direct solver can > solve the problem (and produce a correct-looking solution!), then > maybe BiCGStab is not the right choice. > For nonsymmetric linear system of equations could you suggest a direct solver implemented in dealii library with which I can check if the implementation I have is correct or the choice of Solver is wrong? > * The matrix may not be invertible. This, as well, can be tested with > a direct solver. > Regards, Vinayak Gholap, FAU Erlangen, Germany. -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
