> > In general, it's best to give up on ideas like "tri-diagonal matrices" > when using a general, multi-dimensional, mesh-adaptive finite-element > code. The set of problems that could actually generate tri-diagonal > matrices is incredibly small. Don't worry about the matrix and just use a > good solver like GMRES.
I agree. In my problem I need to invert the matrix instead of solving a linear system. We can get away by inverting just the diagonal blocks if the matrix happens to be block tri-diagonal and save a lot of memory and compute time this way. Do you have a structured 3D "Cartesian" mesh? What numbering of your mesh > would you expect to give you a block tri-diagonal matrix? Yes, I have a 3D cuboid mesh generated using build_cube or a similar algorithm. I guess you can imagine the mesh partitioned into slabs perpendicular to the x axis. Then, the only connectivity is between neighboring slabs and it will give a block tri-diagonal matrix. Thanks, Harshad On Fri, Jul 1, 2016 at 2:55 PM, John Peterson <jwpeter...@gmail.com> wrote: > > > On Fri, Jul 1, 2016 at 12:43 PM, Harshad Sahasrabudhe <hsaha...@purdue.edu > > wrote: > >> Thanks! I don't necessarily want to place each partition on a processor. >> The idea is to renumber the DOF indices such that the matrix looks like a >> block tri-diagonal matrix. I am limited to first order Lagrange elements >> and probably a trapezoidal integration rule. >> >> If I call renumber_nodes_and_elements after using LinearPartitioner, will >> the resulting DOFs make a block tri-diagonal matrix? >> > > Possibly, but this has nothing to do with partitioning, as Derek mentioned. > > Do you have a structured 3D "Cartesian" mesh? What numbering of your mesh > would you expect to give you a block tri-diagonal matrix? I am not aware > of one that does this, and the algorithm used for renumbering in > renumber_nodes_and_elements() certainly doesn't guarantee it. > > -- > John > ------------------------------------------------------------------------------ Attend Shape: An AT&T Tech Expo July 15-16. Meet us at AT&T Park in San Francisco, CA to explore cutting-edge tech and listen to tech luminaries present their vision of the future. This family event has something for everyone, including kids. Get more information and register today. http://sdm.link/attshape _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
