Dear all, I am trying to implement a stabiliazed weak form (e.g. advection-diffusion) where the stabilization tensor is computed element-wise through a standard bubble: \Pi(1-x_i^2). It seems that FE_Q_Bubbles should provides all I need, but here are two things I am not quite clear about,
1. Is the definition of bubble function in FE_Q_Bubbles in [0,1] span or [-1,1] span? Does it has the standard bubble shape (1 at element center and vanishes at the edges)? The (2x_j-1)^{p-1} part is a little bit confusing to me. The bubble function corresponds to linear element in FE_Q_Bubbles is the standard bubble that I desire, but I am really confusing at the shape of this expression at higher orders. 2. I tried to utilize this class (i.e., FE_Q_Bubbles). One issue is that it takes the virtual nodes of the bubble function into account of the total DOFs, which is not the way we prefer in the stabilization method. I hope the bubble function only provides a local support to estimate the stabilization parameter but not involved into the global linear system. How can I deactive the dofs of bubble function when I distributed the dofs like dof_handler.distribute_dofs(fe) in the tutorial. I am pretty new with dealii. Any clue or reference paper is fine. Thanks you guys in advance. -- 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. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/31747ecd-6fc7-4e1b-bbba-1210e680976an%40googlegroups.com.