On Wed, May 17, 2023 at 3:23 PM Matthew Knepley <knep...@gmail.com> wrote:
> On Wed, May 17, 2023 at 2:59 PM Barry Smith <bsm...@petsc.dev> wrote: > >> >> Absolutely, that is fundamental to the design. >> >> In the simple case where all the degrees of freedom exist at the same >> grid points, hence storage is like u,v,t,p in the vector the nesting is >> trivial. You indicate the fields without using IS (don't even need to >> change any code) >> >> -pc_fieldsplit_0_fields 0,1,2 >> -fieldsplit_pc_fieldsplit_0_fields 0,1 >> >> Listing the two complimentary fields >> pc_fieldsplit_1_fields 3 >> -fieldsplit_pc_fieldsplit_1_fields 2 >> should be optional (I can't remember if it is smart enough to allow not >> listing them) >> >> If you have a staggered grid then indicating the fields is trickery >> (since you don't have the simple u,v,t,p layout of the degrees of freedom) >> > > Here we do something similar. > The URL was missing: https://arxiv.org/abs/1808.08328 Thanks, Matt > Thanks, > > Matt > > >> > On May 17, 2023, at 12:47 PM, Alexander Lindsay < >> alexlindsay...@gmail.com> wrote: >> > >> > I've seen threads in the archives about nested field split but I'm not >> sure they match what I'm asking about. >> > >> > I'm doing a Schur field split for a porous version of incompressible >> Navier-Stokes. In addition to pressure and velocity fields, we have fluid >> and solid temperature fields. I plan to put all primal variables in one >> split and the pressure obviously in the Schur split. Now within the "primal >> variable split" a user is wondering whether we can do a further split, e.g. >> perhaps an additive split with the solid temperature split out from the >> velocities and fluid temperature (the former is almost pure conduction >> whereas the latter may be advection dominated). Is this possible? >> > >> > Alex >> >> > > -- > What most experimenters take for granted before they begin their > experiments is infinitely more interesting than any results to which their > experiments lead. > -- Norbert Wiener > > https://www.cse.buffalo.edu/~knepley/ > <http://www.cse.buffalo.edu/~knepley/> > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>