My starting point is a fine mesh of a real geometry that was generated by someone else. To be more precise, what I have is an STL geometry of a surface which is made of rather fine triangles. I have an algorithm to generate the mesh in the volume enclosed by the surface, but this volume mesh will be very fine, as it starts from a fine STL file.
So, I was thinking of coarsening the STL first (at least where I need less resolution, say in flatter regions) and rerun my algorithm, which will then create a coarser mesh. I need a mesh as coarse as possible to begin with, because I am building geometric multigrid operators on it, so I start from a coarse level and I build projections (I will then get the restrictors as transposes). Any suggestions? giorgio On Fri, Mar 4, 2016 at 8:06 PM, Cody Permann <codyperm...@gmail.com> wrote: > You can't coarsen beyond the original mesh. However can you approach the > problem differently? I suggest you start from a coarse mesh, refine it > several times up front to recover a suitable fine mesh, then run your > simulation. Depending your needs that initial refinement can be uniform or > it can adapt to some initial condition if necessary. > On Fri, Mar 4, 2016 at 5:01 PM Giorgio Bornia <giorgio.bor...@gmail.com> > wrote: > >> I have an original mesh that I need to coarsen. >> So does the previous answer mean that I cannot process it with libmesh >> for that purpose? >> >> If so, are there any tools around that do that? >> >> Best, >> Giorgio >> >> >> >> On Wed, Feb 10, 2016 at 5:21 PM, John Peterson <jwpeter...@gmail.com> >> wrote: >> >> > On Wed, Feb 10, 2016 at 4:20 PM, Junchao Zhang <junchao.zh...@gmail.com >> > >> > wrote: >> > >> > > In libmesh, can adjacent elements be coarsened into new elements >> that >> > do >> > > not exist before? For example, a 2x2 grid (mesh) is refined into 4x4 >> > grid. >> > > Can the interior 4 elements be coarsened into one? >> > > I feel it is mathematically allowed, but don't know if it is >> feasible >> > in >> > > practice. >> > > >> > >> > No, you cannot coarsen beyond the level of the original mesh. >> > >> > -- >> > John >> > >> > >> ------------------------------------------------------------------------------ >> > Site24x7 APM Insight: Get Deep Visibility into Application Performance >> > APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month >> > Monitor end-to-end web transactions and take corrective actions now >> > Troubleshoot faster and improve end-user experience. Signup Now! >> > http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 >> > _______________________________________________ >> > Libmesh-users mailing list >> > Libmesh-users@lists.sourceforge.net >> > https://lists.sourceforge.net/lists/listinfo/libmesh-users >> > >> >> >> >> -- >> Giorgio Bornia, Ph.D. >> Assistant Professor >> Department of Mathematics and Statistics >> Texas Tech University >> Lubbock, TX 79409-1042 >> phone: +1 806.834.8754 >> fax: +1 806.742.1112 >> website: http://www.math.ttu.edu/~gbornia >> >> ------------------------------------------------------------------------------ >> _______________________________________________ >> Libmesh-users mailing list >> Libmesh-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/libmesh-users >> > -- Giorgio Bornia, Ph.D. Assistant Professor Department of Mathematics and Statistics Texas Tech University Lubbock, TX 79409-1042 phone: +1 806.834.8754 fax: +1 806.742.1112 website: http://www.math.ttu.edu/~gbornia ------------------------------------------------------------------------------ _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
