> On Feb 14, 2017, at 7:57 PM, Bernardo Rocha <[email protected]> > wrote: > > No particular reason. Let's say it was the first approach I tried in an old > code. > > OK, so to get it working I should use the interlaced version for the ordering > of my dofs. > It does not require too much coding on my side. > > Just to know, if I wanted to insist in the non-interlaced, to keep using > Hypre/BoomerAMG from PETSc I would need to write some code in PETSc for > wrapping this feature (AMGSetDofFunc), right? > > Thanks. > > On Tue, Feb 14, 2017 at 11:48 PM, Barry Smith <[email protected]> wrote: > > Ahh, thanks for the explanation. What a nutso API: way to general, they > should just support interlaced and non-interlaced. > > Anyways we strongly recommend using the interlaced version; for most > calculations it gives much better locality for cache lines and cache. We > always use interlaced. Any particular reason you use non-interlaced?
Yes, you would have to add a call to HYPRE_BoomerAMGSetDofFunc() with the information as you computed. For trying things out the easily way would be to just stick it in an appropriate place in hypre.c Barry > > Barry > > > On Feb 14, 2017, at 7:17 PM, Bernardo Rocha > > <[email protected]> wrote: > > > > Thanks a lot for the reply. > > > > From my understanding and specifically for my problem I would have to use > > the AMGSetDofFunc as follows: > > > > nsyseq = 3; > > for (i=0; i<nsyseq; i++) > > for (k=0; k<N; k++) // N: number of nodes > > { > > eqnIndex[i*N+k] = i; > > } > > HYPRE_BoomerAMGSetDofFunc(preconditioner, eqnIndex); > > > > For a system of 3 PDEs (e.g. linear elasticity in 3D) the default > > behaviour of the nodal coarsening in BoomerAMG, considers an array that is > > filled with > > > > eqnIndex = 0 1 2 0 1 2 0 1 2....0 1 2 > > > > > HYPRE_BoomerAMGSetDofFunc > > > > I could not find an indication of that this is suppose to be setting; it > > is mentioned in the users manual but I don't know what it means. It looks > > like it takes an integer array but I don't even know how long that array is. > > > > If you figure out what it means and can add support for it we'll take it > > as a pull request. > > > > OK Barry, I will try to specify the block size of the matrix. > > But I'm not sure if the block size would be 3 or N (number of nodes). > > This is my ordering of the displacements: [ux1, ux2, ..., uxN, uy1, > > uy2,...uyN, uz1, uz2, ..., uzN] > > > > > HYPRE_BoomerAMGSetNumFunctions > > > > Set the block size of the matrix; this information is then transferred > > automatically to hypre. Note that you can set a block size even for AIJ > > matrices. > > > > Best regards, > > Bernardo > >
