Generally speaking, yes. But this is VIRS where I am enforcing maximum principles. From what I have seen, the residual typically exhibit this behavior if there are very few violations in the first place.
How would I "terminate on stagnation"? On Wed, Nov 30, 2016 at 8:48 PM, Matthew Knepley <[email protected]> wrote: > On Wed, Nov 30, 2016 at 8:38 PM, Justin Chang <[email protected]> wrote: > >> By manually terminating I meant setting -snes_max_it to 5 if I know >> DIVERGED_LINE_SEARCH >> occurs after 6 iterations. In a transient simulation I cannot do this >> > > Let me elaborate. I mean that using DIVERGED_LINE_SEARCH as an indication > of convergence is dicey. It may be that in the problem > you looked at this was true, but I see no reason to believe its true in > general. Why does your residual quit decreasing? > > Thanks, > > Matt > > >> On Wed, Nov 30, 2016 at 8:35 PM, Matthew Knepley <[email protected]> >> wrote: >> >>> On Wed, Nov 30, 2016 at 8:27 PM, Justin Chang <[email protected]> >>> wrote: >>> >>>> Hi all, >>>> >>>> I am running some transient simulations using SNESVINEWTONRSLS. At >>>> certain timesteps, I get a "DIVERGED_LINE_SEARCH" which essentially >>>> "resets" my solution to zero and messes everything up. I notice that this >>>> happens when the SNES Function norm no longer decreases, and if I were to >>>> manually terminate the solver right before the final iteration I get the >>>> answer I want. >>>> >>> >>> Yes, its possible, however isn't that a dangerous way to terminate? >>> Couldn't you terminate on stagnation? >>> >>> Thanks, >>> >>> Matt >>> >>> >>>> Is there a way to "detect" this error and use the solution from the >>>> previous non-failing iteration? Setting a fixed maximum iteration doesn't >>>> seem reasonble because every time level will require different numbers of >>>> iterations to converge. >>>> >>>> Thanks, >>>> Justin >>>> >>> >>> >>> >>> -- >>> 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 >>> >> >> > > > -- > 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 >
