Sorry http://www.mcs.anl.gov/petsc/petsc-dev/docs/manualpages/SNES/SNESMonitorSet.html
On Mar 18, 2014, at 10:56 PM, Mani Chandra <[email protected]> wrote: > I can't find SNESSetMonitor in petsc-dev. I get the following error even > after including petscsnes.h > > error: ‘SNESSetMonitor’ was not declared in this scope > > Moreover, there is no manpage for it on the petsc-dev SNES website: > http://www.mcs.anl.gov/petsc/petsc-dev/docs/manualpages/SNES/index.html > > Has it been removed? > > > On Tue, Mar 18, 2014 at 9:11 PM, Barry Smith <[email protected]> wrote: > > On Mar 18, 2014, at 7:54 PM, Mani Chandra <[email protected]> wrote: > > > The residual of the system of equation that I feed into TS with > > TSSetIFunction. I have a system of equations and I want to probe where most > > of the residual is coming from. The reason is that after certain time of > > evolution, the initial residual at the beginning of each time step > > increases by orders of magnitude than what it used to be at the beginning > > of the time step at early times. For ex, say at t=200, the SNES norm at the > > beginning of a TS timestep with the theta method would be something like > > 1.0812 and at t = 300, it would be 2e5 at the beginning. SNES then has to > > work much harder to reach the abs norm levels and so I want to investigate > > what is happening. > > So this is the initial residual in the nonlinear solve. > -snes_monitor_residual works for plotting if it is 2d otherwise write your > own custom SNES monitor routine and call TSGetSNES, SNESSetMonitor(). > > Barry > > > > > > > On Tue, Mar 18, 2014 at 7:48 PM, Jed Brown <[email protected]> wrote: > > Mani Chandra <[email protected]> writes: > > > > > 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. > > > > Residual of what? What are you going to do with it? > > > >
