Thank you for the hint, I had to put also -pc_type fieldsplit, just in case someone else wants to give it a try...
Is there a way to monitor the convergence of the solvers? Another question, is bs, the block size, always equal to the total number of fields? Sorry but I'm a beginner with PETSc. Lorenzo 2010/4/28 Jed Brown <[email protected]> > On Wed, 28 Apr 2010 12:06:47 +0200, Lorenzo Botti <[email protected]> > wrote: > > If my variables are u v w p (3D stokes equation) and I have an equal > order > > approximation > > Can I just do > > > > -pc_fieldsplit_0_fields 0,1,2 > > -pc_fieldsplit_1_fields 3 > > -pc_fieldsplit_type schur > > -pc_filedsplit_block_size <n_dofs_per_variable> > > Yes, and you can control the solver for the velocity block under > -fieldsplit_0_{ksp,pc} and for the Schur complement under > -fieldsplit_1_{ksp,pc}. Note that with some discretizations, like > stabilized Q1-Q1, you may get better results using an unsplit method > (multigrid on the coupled system). This doesn't work with mixed methods > unless you define custom restrictions and smoothing operators. > > Jed > ------------------------------------------------------------------------------ _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
