Use SNESSetUpdate() to provide a callback function that gets called by SNES automatically immediately before each linear solve. Inside your callback use SNESGetFunction(snes,f,NULL,NULL); to access the last computed value of your function, from this you can update your global variable.
Barry > On Feb 14, 2024, at 4:28 PM, Yi Hu <y...@mpie.de> wrote: > > Dear PETSc team, > > I am using a newtonls snes solver. I know that form residual is invoked at > several locations of the algorithm, first evaluated for the rhs of ksp > solver, then several times for obtaining the optimal step of line search. > > In my problem I have a global variable that is updated every time when form > residual is called, which is not desired in the context of netwonls. > Basically, it should be only evaluated for the purpose of rhs of ksp (and not > in line search). So is it possible to know in which context my form residual > is used for? Then I can just skip my line of updating global variable > depending on this condition. If not possible, could you suggest a workaround? > Or do I need to design a customized line search routine? > > Thanks for your help. > > Best regards, > > Yi > > > > ------------------------------------------------- > Stay up to date and follow us on LinkedIn, Twitter and YouTube. > > Max-Planck-Institut für Eisenforschung GmbH > Max-Planck-Straße 1 > D-40237 Düsseldorf > Handelsregister B 2533 Amtsgericht Düsseldorf > Geschäftsführung > Prof. Dr. Gerhard Dehm > Prof. Dr. Jörg Neugebauer > Prof. Dr. Dierk Raabe > Dr. Kai de Weldige > Ust.-Id.-Nr.: DE 11 93 58 514 Steuernummer: 105 5891 1000 > > > Please consider that invitations and e-mails of our institute are only valid > if they end with …@mpie.de. If you are not sure of the validity please > contact r...@mpie.de > > Bitte beachten Sie, dass Einladungen zu Veranstaltungen und E-Mails > aus unserem Haus nur mit der Endung …@mpie.de gültig sind. In Zweifelsfällen > wenden Sie sich bitte an r...@mpie.de > ------------------------------------------------- >
