On Thu, Oct 20, 2022 at 9:42 AM Gong Yujie <yc17...@connect.um.edu.mo> wrote:
> Dear development team, > > I'm trying to write a code to solve a partial differential equation. I > didn't use PETSc's discretization. I have a question about the > implementation of the boundary condition (Dirichlet boundary condition). > When implementing the Dirichlet boundary condition. I need to set the > corresponding rows in the Jacobian matrix diagonal 1 and others 0. I > created the matrix use DMCreateMatrix. > For this, you can use https://petsc.org/main/docs/manualpages/Mat/MatZeroRows/ https://petsc.org/main/docs/manualpages/Mat/MatZeroRowsColumns/ > Can I add the Dirichlet boundary condition to the DMPlex mesh so that the > Jacobian matrix won't contain these Dirichlet boundary rows? If yes, is > there a function that can set the Dirichlet boundary points' value? > If you are not using the PETSc discretization, that means you gave a PetscSection to the DMPlex so that it could make the Mat. You can add constraints to that Section in order to eliminate some unknowns. Thanks, Matt > Best Regards, > Jerry > > -- 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/>