Thanks for your instant and helpful answer. So, the grid from other mesh generator cannot be made coarser at all. As I referred from step-5 tutorial, I guess a procedure like associating the surface boundaries (from meshing software) to the manifolds would also only works for meshing refinement, not for mesh coarsening. Vào lúc 00:09:00 UTC+9 ngày Thứ Tư, 1 tháng 9, 2021, [email protected] đã viết:
> Dear Truong, > My understanding is that the triangulation in deal.II works like a > quad/oct-forest.That is, the mesh that is generated or read serves as the > forest and each cell is a tree. Consequently, it is not possible to coarsen > a mesh more than it's initial configuration. > > For a lot of meshes generated by deal.II, this is not a problem since they > contain a very low number of cells (for example, a cubic grid has 1 cell in > it's coarsest level, hence it is a forest with once tree). However, if you > read your mesh from an external source, you cannot make it coarser than it > is when you have read it. > > My suggestions would be to make a coarse abacus mesh, then you refine it > within deal.II. This way you would have a coarsest level with as few cell a > possible, then you could refine it adaptively. As far as I know, it is not > possible to coarsen a mesh below it's level 0, because this would imply > "merging cell". > > I hope that was sufficiently clear. > Best of luck! > Bruno > > On Tuesday, August 31, 2021 at 9:26:32 a.m. UTC-4 > [email protected] wrote: > >> Hello everyone, >> I am new to deal.II and I am playing around with the grid of L-shape >> which is imported from Abaqus input file using GridIn::read_abaqus(). The >> grid has been successfully read as well as the boundary indicators ( from >> the surface with the name of "SS1" and "SS2"). However, when I try to do >> coarsening the grid by setting cell->set_coarsen_flag(), nothing happened. >> I also tested with adaptive refinement as in step-6, only a figure of the >> new cell has been generated, none has been coarsened even I set the >> coarsening ratio to high value. >> I wonder what is wrong here or is there something that I misunderstand >> with the code. Thanks in advance. >> >> [image: Capture.PNG] >> [image: Capture.PNG] >> > -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/c674a25b-0daa-4cdf-bd78-c64a90a5a86fn%40googlegroups.com.
