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

[Barry Smith]

  The more adaptors the better


> On Apr 15, 2015, at 8:51 PM, Emil Constantinescu <emconsta at mcs.anl.gov> wrote:
> 
> 
> On 3/24/15 5:31 AM, Lisandro Dalcin wrote:
>> Emil, is there any chance you can try my code with your problem? I
>> really need some feedback to push this to PETSc, otherwise
> 
> Hi Lisandro - we checked ts_alpha_adapt and we tested it on a small system (mildly stiff van der Pol ODE). I enclosed a Figure generated by Debo that compares the error at the final time against ATOL - there alpha is the original one (with original adaptor). For this problem your adaptor works better [ error should be close to ATOL]. So from my perspective, your adaptor works well. However, we need to keep the old too so that we have a one step adaptor available ... since alpha is a one step method.
> 
> Emil
> <Figure2.pdf>