On Sun, Apr 1, 2018 at 10:26 PM, <ss.k...@pusan.ac.kr> wrote: > Hello, all. > > > > I try to derive an RB error bound using the min-theta approach. > > First of all, I saw the RB example 1 because this example shows the value > of > coercivity constant lower bound, not dummy value. > > However, this example does not satisfy requirements of the min-theta > approach. > > > > If so, how was the lower bound value of the example 1 obtained? > > I do not know why the lower bound value is 0.05 in the RB example 1. >
If I recall correctly, the ThetaA1 and ThetaA2 are irrelevant to the coercivity constant because they give a divergence-free convection field (it's clearly divergence free since the field is constant everywhere, given by the parameters x_vel and y_vel). As a result we can set the coercivty lower bound to be the value returned by ThetaA0, which is 0.05. Of course, this is a simple case, and in general one must use SCM to get the coercivity lower bound. I would say that in practice a lot of people are satisfied with skipping the SCM and just setting a dummy value (e.g. 1) for the coercivity lower bound. This means that the error bound isn't rigorous anymore, but it's still useful as an error indicator. David ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
