[petsc-users] Fortran: PetscDSRestoreTabulation + PetscDSGetTabulation

[Barry Smith]

   The interface definition and Fortran stub look ok to my eyeballs. However, eyeballs cannot compile code, so using the debugger to determine the cause of the crash is best.

   Barry



> On Aug 29, 2024, at 5:18 PM, Matthew Knepley <knepley at gmail.com> wrote:
> 
> On Thu, Aug 29, 2024 at 9:57 AM Martin Diehl <martin.diehl at kuleuven.be <mailto:martin.diehl at kuleuven.be>> wrote:
>> Dear PETSc team,
>> 
>> I have a question regarding the use of PetscDSGetTabulation from
>> Fortran.
>> PetscDSGetTabulation has a slightly different function signature
>> between Fortran and C. In addition, there is an (undocumented)
>> PetscDSRestoreTabulation in Fortran which cleans up the arrays. Calling
>> it results in a segmentation fault.
>> 
>> I believe that PetscDSRestoreTabulation is not needed. At least our
>> Fortran FEM code compiles and runs without it. However, we have
>> convergence issues that we don't understand so any suspicious code is
>> currently under investigation.
> 
> This may be due to my weak Fortran knowledge. Here is the code
> 
>   https://urldefense.us/v3/__https://gitlab.com/petsc/petsc/-/blob/main/src/dm/dt/interface/f90-custom/zdtdsf90.c?ref_type=heads__;!!G_uCfscf7eWS!c6UMUopH2bMHgSiLAqHoFUrJqajqcyYKZ3EFjfB_9tp9k8ByFqwf12a_M6JkOBU2tA3kSC5h83TvWw9kIrmuwic$ 
> 
> I call F90Array1dCreate() in the GetTabulation and F90Array1dDestroy() in the RestoreTabulation(), which I thought
> was right. However, I remember something about interface declarations, which have now moved somewhere I cannot find.
> 
> Barry, is the interface declaration for this function correct?
> 
>   Thanks,
> 
>       Matt
>  
>> best regards,
>> Martin
>> 
>> -- 
>> KU Leuven
>> Department of Computer Science
>> Department of Materials Engineering
>> Celestijnenlaan 200a
>> 3001 Leuven, Belgium
>> 
> 
> 
> --
> What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
> -- Norbert Wiener
> 
> https://urldefense.us/v3/__https://www.cse.buffalo.edu/*knepley/__;fg!!G_uCfscf7eWS!c6UMUopH2bMHgSiLAqHoFUrJqajqcyYKZ3EFjfB_9tp9k8ByFqwf12a_M6JkOBU2tA3kSC5h83TvWw9kyCZ6mUM$  <https://urldefense.us/v3/__http://www.cse.buffalo.edu/*knepley/__;fg!!G_uCfscf7eWS!c6UMUopH2bMHgSiLAqHoFUrJqajqcyYKZ3EFjfB_9tp9k8ByFqwf12a_M6JkOBU2tA3kSC5h83TvWw9kZ05AVyI$ >

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