[Trilinos-Users] Rythmos problem: getStepStatus()

[Bartlett, Roscoe A.]

Cristiano,

You should be able to get x or x_dot at any point in the range [t, t+dt] for the current time step by calling getPoints(...).  The status returned from getStepStatus() is not really supposed to give all info, just the "free" stuff.

Some of the newer Rythmos maintainers may be able to provide more detail.

-Ross

P.S. AKA rabartl


> -----Original Message-----
> From: trilinos-users-bounces at software.sandia.gov [mailto:trilinos-users-
> bounces at software.sandia.gov] On Behalf Of Cristiano Malossi
> Sent: Wednesday, January 11, 2012 9:22 AM
> To: trilinos-users at software.sandia.gov
> Subject: [Trilinos-Users] Rythmos problem: getStepStatus()
> 
> Hello,
> 
> I have a question about Rythmos. In particular, I am using the Implicit
> BDF stepper, that integrates DAEs with a variable step size. The solver
> apparently works, however I cannot access the derivative of the
> solution, that I need.
> 
> On line 487 of the file Rythmos_ImplicitBDFStepper_def.hpp it is written:
> 
>    stepStatus.solutionDot = Teuchos::null; // This is *not* free!
> 
> where it is not clear to me what the comment means.
> On the top of the method there is another comment:
> 
>    // 2007/08/24: rabartl: We agreed that getStepStatus() would be free
>    // so I have commented out removed all code that is not free
> 
> In the documentation it is written that the code is a re-implementation
> of LLNL Sundials IDA library, that should be free. Could you please give
> me some information about this issue? It is possible to fix this method
> or have a patch to make it working?
> 
> Note that the same problem appears with the Implicit Runge-Kutta method.
> 
> Thank you.
> Best regards,
> 
>      Cristiano Malossi
> 
> --
>         Cristiano Malossi
>         Ph.D. Student
> 
>         EPFL - SB - SMA - MATHICSE
>         CMCS - Modelling and Scientific Computing
>         Office MA C2 577, Av.Piccard, Station 8.
>         CH-1015 Lausanne (Switzerland)
>         Ph.    : +41 21 69 32733
>         E-mail : cristiano.malossi at epfl.ch
> 
> 
> _______________________________________________
> Trilinos-Users mailing list
> Trilinos-Users at software.sandia.gov
> http://software.sandia.gov/mailman/listinfo/trilinos-users