[petsc-dev] [petsc-maint #59097] TSTheta

[Barry Smith]

  Michael,

   We intentionally have kept Jed off the petsc-maint email list so he can get work done. This can be discussed in the petsc-dev at mcs.anl.gov list 

   Barry

On Dec 21, 2010, at 4:26 PM, Michael E Henderson wrote:

> Hi,
> 
> Who can I talk to about the implementation of the TSTheta Implicit time 
> stepper?
> 
> The implementation computes ts->vec_sol which solves the implicit system. 
> But the monitor returns ts->vec_sol+dt*th->Xdot, which does not 
> necessarily satisfy the equations. At least that's how I read the code. I 
> think that the call to VecAXPY which changes ts->vec_sol needs to be moved 
> to after the call to TSMonitor in src/ts/impls/implicit/theta/theta.c 
> Purely a matter of what is passed to the monitor routine.
> 
> Thanks,
> 
> Mike Henderson
> ------------------------------------------------------------------------------------------------------------------------------------
> Mathematical Sciences, TJ Watson Research Center
> mhender at watson.ibm.com
> http://www.research.ibm.com/people/h/henderson/
> http://multifario.sourceforge.net/
> 
> Hi, 
> 
> Who can I talk to about the implementation of the TSTheta Implicit time stepper? 
> 
> The implementation computes ts->vec_sol which solves the implicit system. But the monitor returns ts->vec_sol+dt*th->Xdot, which does not necessarily satisfy the equations. At least that's how I read the code. I think that the call to VecAXPY which changes ts->vec_sol needs to be moved to after the call to TSMonitor in src/ts/impls/implicit/theta/theta.c Purely a matter of what is passed to the monitor routine. 
> 
> Thanks, 
> 
> Mike Henderson
> ------------------------------------------------------------------------------------------------------------------------------------
> Mathematical Sciences, TJ Watson Research Center
> mhender at watson.ibm.com
> http://www.research.ibm.com/people/h/henderson/
> http://multifario.sourceforge.net/