> What is the meaning of tol in SolverControl ? Is it checked against L2 norm > of residual or is the residual normalized with right hand side ? The > documentation does not explain this.
It is typically the l2 norm of the residual which gets compared to the tolerance. It is not scaled by the right hand side, so you might want to use something like 1e-10*rhs.l2_norm() as the stopping criterion. Note that I wrote "typically" because it depends on the solver what is handed over to the SolverControl. Methods where the true residual Ax-b is expensive to calculate and is not there for free in the iterative process (like BiCGStab for example) use the pseudo residual. Note that this can be configured for BiCGStab for example. -- Timo Heister http://num.math.uni-goettingen.de/~heister _______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
