https://petsc.org/release/manualpages/SNES/SNESSetForceIteration/#snessetforceiteration
> On Sep 2, 2023, at 3:04 PM, David Knezevic via petsc-users > <[email protected]> wrote: > > Hi all, > > I'm using the SNES solver for a plasticity model, and the issue I've run into > is that in some time steps the solver terminates after "NL step 0" since the > initial residual (based on the solution from the previous time step) is below > the specified tolerance. > > I gather that "NL step 0" only checks the residual and doesn't actually do a > Newtown update, and hence it seems that this is leading to inaccurate results > in some cases. I can of course specify a smaller convergence tolerance to > avoid this issue, but I've found it difficult to find a smaller tolerance > that works well in all cases (e.g. it leads to too many iterations or > non-convergence). So instead what I would like to do is ensure that the > solver does at least 1 Newton iteration instead of terminating at "NL step > 0". Is there a way to enforce this behavior, e.g. by skipping "NL step 0", or > specifying a "minimum number of iterations"? I didn't see anything like this > in the documentation, so I was wondering if there are any suggestions on how > to proceed for this. > > Thanks, > David
