[petsc-users] TimeStepper norm problems. EMIL Please read this

Emil Constantinescu emconsta at mcs.anl.gov
Mon Mar 30 20:23:55 CDT 2015

Hi Andrew,

Sorry for the delay; things are going slower with me over the spring 
break but we are working on it.

The problem that you see may not be related to the integrator, which 
runs well (we get expected convergence rates and good results) for other 
problems, in particular, for problems with real variables (and no 
c++11). So the high level th->endpoint implementation seems fine.

For some reason the linear solver is misbehaving when using cn. If you 
use option -snes_mf the problem disappears.

Please do not use -ts_theta_adapt until it is fixed.

In conclusion I don't think that looking at theta.c will be productive. 
We are currently looking at what happens at the lower levels.


On 3/30/15 4:25 PM, Andrew Spott wrote:
> Emil:  If I want to fix this myself, do you have any idea where I should
> start looking?  I assume in the th->endpoint section of TSStep_Theta in
> http://www.mcs.anl.gov/petsc/petsc-current/src/ts/impls/implicit/theta/theta.c.html?
> Thanks,
> -Andrew

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