On Thu, Nov 01, 2012 at 07:49:03AM +0000, Garth N. Wells wrote: > I've added a demo for solving singular systems using a Krylov solver via > PETSc: > > demo/undocumented/singular > > This can provide a good alternative to, for example, pinning the > pressure in a Stokes problem or using a global Lagrange multiplier. In > contrast to pinning or Lagrange multipliers, it doesn't mess up > preconditioners or introduce a global row to the matrix.
Very useful. What is exactly the logic of null_space = Vector(u.vector()) V.dofmap().set(null_space, 1.0) solver.set_nullspace([null_space]) ? Why does the dofmap need to be involved? > Does anyone know if Trilinos/AztecOO has similar functionality to > PETSc for solving singular problems? No idea. -- Anders _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : dolfin@lists.launchpad.net Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
