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

Andrew Spott ansp6066 at colorado.edu
Mon Mar 30 21:32:45 CDT 2015

I’m sorry, I didn’t want to imply you were taking too much time.  I was just interested in trying to solve the problem myself, especially if it was a simpler fix.

I don’t have enough of an understanding of the internals of PETSc though, if it depends on the compiler flags.

Good luck!



On Mon, Mar 30, 2015 at 7:23 PM, Emil Constantinescu <emconsta at mcs.anl.gov>

> 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.
> Thanks,
> Emil
> 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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