Hi PETSc users, I am working with a code that solves a set of PDEs on a rectangular domain with Neumann boundary conditions. My understanding of implementing the boundary condition is that I should set the boundary value to be the value that makes the finite difference derivative go to zero (or some other prescribed value) on that boundary.
I was attempting to update the solution from TS using a pre- or post-step/stage function and TSGetSolution, but this does not appear to work as expected. What would be the correct way to prescribe the boundary condition, given that I'm using TSRK for timestepping and a DMDA for discretization? Looking forward to any help! Ellen Price
