Hi Barry, So for Newton solvers that would work by explicitly setting the boundary conditions in my gradient(function) and Jacobian vectors. But in quasi-Newton solvers where the Jacobian is built from a history of previous Jacobians and current gradient vector, I can't enforce a new boundary condition. I can change the current gradient vector appropriately but I don't see a way handle the the Jacobian.
Thanks, Bikash On Fri, Nov 3, 2017 at 6:20 PM, Smith, Barry F. <[email protected]> wrote: > > > You should not need to "tamper" with the solution process to achieve > this. > > I would just change how my FormFunction and FormJacobian behave to > implement the different boundary conditions. Why would that not work? > > Barry > > > On Nov 3, 2017, at 4:39 PM, Bikash Kanungo <[email protected]> wrote: > > > > Hi Matt, > > > > I want to update the Dirichlet boundary condition on the solution vector > on-the-fly. One way to do it is to destroy the current snes solver and > create a new one with the new Dirichlet boundary condition (which means > setting a new solution vector with a different size, size = # of > non-Dirichlet rows). But is it possible to work with the current snes and > instead enforce the new Dirichlet boundary condition on the current > solution vector? > > > > Thanks, > > Bikash > > > > On Fri, Nov 3, 2017 at 5:19 PM, Matthew Knepley <[email protected]> > wrote: > > What do you want to do to it? > > > > Matt > > > > On Fri, Nov 3, 2017 at 5:14 PM, Bikash Kanungo <[email protected]> wrote: > > Hi, > > > > I'm trying to solve a nonlinear problem using BFGS Quasi-Newton solver. > I would like to tamper the solution vector x on-the-fly, based on some > criterion. Is there a way to do so? Will SNESGetSolution(SNES snes, Vec * > x) allow me to do so for each SNES iteration? > > > > Thanks, > > Bikash > > > > -- > > Bikash S. Kanungo > > PhD Student > > Computational Materials Physics Group > > Mechanical Engineering > > University of Michigan > > > > > > > > > > -- > > 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/ > > > > > > > > -- > > Bikash S. Kanungo > > PhD Student > > Computational Materials Physics Group > > Mechanical Engineering > > University of Michigan > > > > -- Bikash S. Kanungo PhD Student Computational Materials Physics Group Mechanical Engineering University of Michigan
