Hi, Is there anyway I can get the residual at the beginning of the time step? I tried TSSetPreStage and TSSetPreStep but they didn't work. Setting TSSetPreStage would crash the program even if there is nothing in the routine that I set and TSSetPreStep would give me the residual at the end of the previous time step. I want to take a look at the residual at the beginning of the new time step before the nonlinear solver starts.
Thanks, Mani On Sat, Mar 15, 2014 at 9:03 PM, Barry Smith <[email protected]> wrote: > > Yes but it is slightly complicated. You need to configure PETSc with > —with-afterimage and run the program with -draw_save then it will save > each image. > > It will open an X window to display each image. You can run with > -x_virtual to skip the opening of X windows but then you need Xvfb to be > installed > > Barry > > > On Mar 15, 2014, at 6:29 PM, Mani Chandra <[email protected]> wrote: > > > -snes_montior_residual is really cool. Anyway I could get it to spit out > png images instead of on screen visualization? > > > > > > On Sat, Mar 15, 2014 at 6:24 PM, Barry Smith <[email protected]> wrote: > > > > > > You can write a custom monitor and set it with TSMonitorSet() > > > > This routine would call TSGetSNES() then SNESGetSolution() then call > SNESComputeFunction() then call VecView() on the result. > > > > But note that just because the residual is big somewhere doesn’t > mean the error need be. > > > > You could also run with -snes_monitor_residual to see how the > residual is being reduced inside the nonlinear solve (that is, what parts > of the residual are most stubborn). > > > > > > Barry > > > > > > On Mar 15, 2014, at 5:47 PM, Mani Chandra <[email protected]> wrote: > > > > > Hi, > > > > > > Is there anyway I can VecView the residual after TS has completed an > implicit time step? I'd like to see where in my domain most of the errors > are coming from. I looked at TSMonitor but that doesn't seem to give me > access to the residual at the end of the current time step. > > > > > > Thanks, > > > Mani > > > > > >
