[petsc-users] Adaptive time stepping for implicit solvers

[Barry Smith]

  You might consider using the Event feature of TS to manage this. It detects when your "indicator function" changes sign and stops the integration right at that point allowing you to change your ODE or do what ever you need. It allows managing discontinuous changes in the ODE without needing smoothing (that messes up the solution). 

  You would write an indicator function that depends on "solution of heat equation equal to a given parameter"

I am including Shri and Emil on this message because they understand the event handling the best (Shri wrote it).
  
  Barry


> On Sep 30, 2020, at 11:58 AM, Salazar De Troya, Miguel via petsc-users <petsc-users at mcs.anl.gov> wrote:
> 
> Hello,
>  
> I have a heat equation with a right-hand side coefficient that changes sign when a certain condition is met (solution of heat equation equal to a given parameter). I am thinking of modeling the sign change with a smoothed-out Heaviside approximation and let the solver adjust the time step to capture the sudden transition. Given that it is a heat equation, I am interested in using an implicit solver. Which ones in the TS suite also have adaptive capabilities?
>  
> Thanks
> Miguel
>  
> Miguel A. Salazar de Troya
> Postdoctoral Researcher, Lawrence Livermore National Laboratory
> B141
> Rm: 1085-5
> Ph: 1(925) 422-6411

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