Thank you for the clarification. Barry Smith <bsm...@petsc.dev> 于2023年3月14日周二 13:27写道：
> > To gain an advantage in reusing the KSP the Mat must be the same size > and the Mat must have the same nonzero structure (different numerical > values are fine). Otherwise there is no measurable improvement in reusing > the same KSP. > > Barry > > > > On Mar 14, 2023, at 7:25 AM, K. Wu <wuktsing...@gmail.com> wrote: > > > > Hi all, > > > > Good day! > > > > I am trying to solve an optimization problem where I need to solve > multiple successive linear systems inside each optimization loop. The > matrices are based on the same grid, but their data structure will change > for each linear system. > > > > Currently I am doing it by setting up just one single KSP object. Then > call KSPSetOperators() and KSPSolve() for each solve. This means the KSP > object is solving the successive linear systems one by one, and in the next > optimization iteration, it starts all over again. > > > > I am wondering that should I use separate KSP objects for each linear > system so that during optimization the same KSP will be specialized in > solving its corresponding system all the time? > > > > I use non-zero initial guess, so I pay attention to use different x > vectors for different linear systems, so that the x vectors from the > previous iteration can be used as initial guesses for linear systems in the > next iteration. Not sure whether some similar thing should also be done for > KSP? > > > > Thanks for your kind help! > > > > Best regards, > > Kai > > > >
