On Thu, Jul 6, 2023 at 3:42 PM YuSh Lo <ysjosh...@gmail.com> wrote:
> Hi, > > I am using SNES to solve some nonlinear functions. > After each iteration, I have an user-defined updating to do. > Some values in the solution vectors must be inserted to some different > location. > I have tried to do it in the beginning of form RHS and form Jacobian, but > the vector is read-only. The results are correct although some warnings are > thrown with debug build saying that the vector is in wrong state. I also > tried setting a function with SNESSetupdate, but the convergence is bad. > Is the vector I get using SNESGetSolution the same as the vector that will > be used in following forming Jacobian and RHS?, and is it again read only? > For these kinds of things, it might be easiest to put this in the line search. I would write a custom line search routine that did your modifications. That way you are assured that it does not short circuit anything else since the line search is where we are updating the solution directly. It should also work in the Update(), and we could try to determine what is wrong here, but that would be more digging. I think making it a line search is easier. Thanks, Matt > Thanks, > Josh > > -- 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/>