Hi Matthew, Thank you. I will try setting up custom linesearch.
Thanks, Josh Matthew Knepley <[email protected]> 於 2023年7月6日 週四 下午3:01寫道： > On Thu, Jul 6, 2023 at 3:42 PM YuSh Lo <[email protected]> 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/> >
