Hello Salazar, On Tue, Sep 6, 2016 at 5:46 PM, Salazar De Troya, Miguel < salazardet...@llnl.gov> wrote:
> Hello > > I started learning about the dual weighted residual error estimator. From > what I read here: http://cadmus.usc.edu/UQ-SummerSchool-2013/bauman.pdf > there are two approaches in libMesh: One, calculate the adjoint solution in > an enriched space; two, use a classic error estimator for both the primal > and the adjoint solutions. I have two questions with regards to this > approach: > > * What is the error incurred by choosing the second option? > The second option (called Adjoint Residual Error Estimator) is suitable for use as an *error indicator*, i.e. the calculation of an element wise metric to decide whether they should be refined. For obtaining reliable error estimates, the first option (Adjoint Refinement Estimator) is the way to go. A combined strategy can also be used, where one does a few mesh refinement steps using the Adjoint Residual approach, and then does a step with the Adjoint Refinement Estimator to check whether error tolerances have been met. > * In the case of elasticity, how do we apply the constitutive tensor? > In both error estimators or just the primal? Basically, in the above > presentation, slide 66, the application of R_k > If you use the Adjoint Refinement Error Estimator, the constitutive tensor is automatically included via the definition of the residual one provides in element_time_deriative. If you use the Adjoint Residual Indicator, and wish to include the effect of the constitutive tensor, you will need to build a weights matrix. See *Adjoints example 3*. If your constitutive tensor is nonlinear, then you will need to use the weighted patch recovery estimator (see src/error_estimation/weighted_patch_recovery_estimator.C), specify the weight functions and provide function pointers to them. *Adjoints example 3* covers this as well. > > Thanks > Miguel > > ------------------------------------------------------------ > ------------------ > _______________________________________________ > Libmesh-users mailing list > Libmesh-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/libmesh-users > Thanks. -- Vikram Garg Postdoctoral Associate The University of Texas at Austin http://vikramvgarg.wordpress.com/ http://www.runforindia.org/runners/vikramg ------------------------------------------------------------------------------ _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
