[petsc-users] Spatial distribution of the residual after an implicit TS timestep

[Barry Smith]

  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 <mc0710 at gmail.com> 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 <bsmith at mcs.anl.gov> 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 <mc0710 at gmail.com> 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
> 
>