[petsc-users] TS tutorial ex11 in Fortran

[Thibault Bridel-Bertomeu]

Good morning all,

Thank you Barry for your answer.
I started adding some interfaces (PetscFVSetComponentName, PetscFVView &
PetscFVSetType so far) and I have to say I think it is working quite well,
but the prototypes of those functions are still quite "simple".
I am stuck at how to implement the wrappers for PetscDSSetRiemannSolver and
PetscDSSetContext though, especially on how to pass a function as an
argument to PetscDSSetRiemannSolver ... Are there any similar functions
that may already have their wrappers ?

Thank you very much,

Thibault


Le sam. 12 déc. 2020 à 23:28, Barry Smith <bsmith at petsc.dev> a écrit :

>
>
> On Dec 12, 2020, at 2:59 PM, Thibault Bridel-Bertomeu <
> thibault.bridelbertomeu at gmail.com> wrote:
>
> Dear Jed, dear Barry,
>
> Thank you for the fast answers !
>
> If I have any success I will make sure to make a pull request to provide
> some version of ex11 in Fortran.
>
> Regarding the stubs, I admit I started looking in that direction to add
> the missing wrappers but I am not sure I fully understand the process yet.
> For each C function, I gotta provide a Fortran interface in a .h90 file as
> well as a C function that has a Fortran-like prototype and calls the C
> function - right ?
>
>
>   Yes,
>
> However there are a few things I could not find / understand yet.
> For instance, it appears that for C functions that have character string
> arguments take an extra argument in their Fortran-like-prototype-wrapper,
> namely the length of the string. Is that passed automatically ? I couldn’t
> find where it could come from ...
>
>
>    This secret argument is put automatically by the Fortran compiler.
>
> Another thing is for functions like PetscFVView. I guess the wrapping is
> less straightforward because I tried a quick something and it segfault’ed.
> I couldnt find the wrapper for DMView although there is such a routine in
> Fortran too. Could you please detail how to wrap such functions ?
>
>
> PETSC_EXTERN void dmview_(DM *da,PetscViewer *vin,PetscErrorCode *ierr)
> {
>   PetscViewer v;
>   PetscPatchDefaultViewers_Fortran(vin,v);
>   *ierr = DMView(*da,v);
> }
>
> dm/interface/ftn-custom/zdmf.c
>
>
>
> Thank you very much again,
>
> Thibault Bridel-Bertomeu
>
> Le sam. 12 déc. 2020 à 21:48, Barry Smith <bsmith at petsc.dev> a écrit :
>
>>
>>    PETSc Fortran interfaces are a combination of automatically generated
>> and manually generated.
>>
>>    For any C PETSc function if the manual page begins with /*@  it
>> generates the Fortran interface automatically (make allfortranstubs).  If
>> it begins /*@C then either the Fortran interface is done manually or is
>> missing.
>>
>>    C functions that have character string arguments or function arguments
>> (or a few other special cases) need to be manually provided.  The
>> automatically generated stubs go in the directory ftn-auto while manually
>> generated ones go in the directory fin-custom.
>>
>>    Perhaps you could first generate a list of "missing" Fortran stubs and
>> then for each stub determine why it is missing and if it can be provided.
>> Some are likely easy to provide but a few (involving function arguments)
>> will be more involved. Once you have all the stubs available translating
>> ex11.c becomes straightforward.
>>
>>   Barry
>>
>>
>> On Dec 12, 2020, at 9:30 AM, Thibault Bridel-Bertomeu <
>> thibault.bridelbertomeu at gmail.com> wrote:
>>
>> Dear all,
>>
>> Is there somewhere a version of the TS tutorial ex11.c in Fortran ?
>> I am looking into building in F90 (let's say that it is an unavoidable
>> constraint) an unstructured 3D solver of the Euler equations using the
>> "new" features of PETSc - mostly DMPlex & PetscFV - but I think there are
>> some interfaces missing and I find it hard to find workarounds in Fortran.
>> I would be grateful if anyone could please give me some pointers ...
>>
>> Thank you very much in advance,
>>
>> Thibault Bridel-Bertomeu
>> —
>> Eng, MSc, PhD
>> Research Engineer
>> CEA/CESTA
>> 33114 LE BARP
>> Tel.: (+33)557046924
>> Mob.: (+33)611025322
>> Mail: thibault.bridelbertomeu at gmail.com
>>
>>
>> --
> Thibault Bridel-Bertomeu
> —
> Eng, MSc, PhD
> Research Engineer
> CEA/CESTA
> 33114 LE BARP
> Tel.: (+33)557046924
> Mob.: (+33)611025322
> Mail: thibault.bridelbertomeu at gmail.com
>
>
>
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