Ok, I'm trying with NonlinearImplicitSystem in the first place. I have a couple of questions...
Is it possible to compute and get the L2 norm of the increment as in example 13, it's a good indication of how the residual is decreasing and it's cheaper to compute compared to the residual norm? Would it be possible to add a metod initial_linear/nonlinear_residual() to Linear/NonlinearImplicitSystem? Actually for a LinearImplicitSystem I need to do std::cout<<"initial linear residual = "<<(dynamic_cast<PetscLinearSolver<Number>*>(ns_system.linear_solver.get()))->get_initial_residual()<<std::endl; Thank you very much Lorenzo 2009/10/12 Lorenzo Botti <[email protected]> > Thanks for the suggestions, I'm going to try both the possibilities. > > Lorenzo > > > Il giorno 12/ott/2009, alle ore 18.01, John Peterson ha scritto: > > > On Mon, Oct 12, 2009 at 10:57 AM, Roy Stogner <[email protected]> >> wrote: >> >>> >>> On Mon, 12 Oct 2009, Lorenzo Botti wrote: >>> >>> I'm solving the incompressible NS equations with a fully implicit dg >>>> code >>>> and I would like >>>> to know if there is an easy way to solve for the increment instead of >>>> the >>>> solution itself. >>>> >>> >>> I'm using a transient_system but maybe there is a best framework to do >>>> that. >>>> >>> >>> The simplest change might be for you to use a >>> TransientSystem<NonlinearImplicitSystem> and solve it with the >>> PetscNonlinearSolver; that expects you to build just the global >>> residual and Jacobian for your time step. A more radical change might >>> be for you to create a FEMSystem subclass; that framework doesn't even >>> require you to worry about the time stepping, just to build the >>> differential and the algebraic parts of element and side residuals in >>> separate methods. >>> >> >> FYI: FEMSystem example in ex18. >> >> -- >> John >> > > ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
