[petsc-users] TS tutorial ex11 in Fortran
Thibault Bridel-Bertomeu
thibault.bridelbertomeu at gmail.com
Sun Dec 13 08:34:06 CST 2020
Hello Matthew,
Thank you for your answer and the pointer to SNESSetFunction(). Is the
PETSC_F90_2PTR_PROTO(ptr) necessary for every wrapper of that category ?
So far, for the PetscDSSetRiemannSolver, I did this :
#ifdef PETSC_HAVE_FORTRAN_CAPS
#define petscdssetriemannsolver_ PETSCDSSETRIEMANNSOLVER
#elif !defined(PETSC_HAVE_FORTRAN_UNDERSCORE) &&
!defined(FORTRANDOUBLEUNDERSCORE)
#define petscdssetriemannsolver_ petscdssetriemannsolver
#endif
PetscFortranCallbackId riemannsolver;
static PetscErrorCode ourriemannsolver(PetscInt dim, PetscInt Nf, PetscReal
x[], PetscReal n[], PetscScalar uL[], PetscScalar uR[], PetscInt
numConstants, PetscScalar constants[], PetscScalar flux[], void *ctx)
{
PetscObjectUseFortranCallback((PetscDS)ctx, riemannsolver, (PetscInt*,
PetscInt*, PetscReal*, PetscReal*, PetscScalar*, PetscScalar*, PetscInt*,
PetscScalar*, PetscScalar*, void*, PetscErrorCode*),
(&dim, &Nf, x, n, uL, uR, &numConstants,
constants, flux, _ctx, &ierr));
}
PETSC_EXTERN void petscdssetriemannsolver_(PetscDS *prob, PetscInt *f,
void (*rs)(PetscInt *dim,
PetscInt *Nf, PetscReal x[], PetscReal n[], PetscScalar uL[], PetscScalar
uR[], PetscInt *numConstants, PetscScalar constants[], PetscScalar flux[],
void *ctx, PetscErrorCode *jerr),
PetscErrorCode *ierr)
{
*ierr = PetscObjectSetFortranCallback((PetscObject)*prob,
PETSC_FORTRAN_CALLBACK_CLASS, &riemannsolver, (PetscVoidFunction)rs, prob);
*ierr = PetscDSSetRiemannSolver(*prob, *f, (void*)ourriemannsolver);
}
It compiles, but I have no idea whether it works or not, and I won't have
until the program is entirely built (with the TS and all) and it actually
has to call a Riemann solver added with that routine.
What do you think ?
Thibault
Le dim. 13 déc. 2020 à 15:29, Matthew Knepley <knepley at gmail.com> a écrit :
> On Sun, Dec 13, 2020 at 9:17 AM Mark Adams <mfadams at lbl.gov> wrote:
>
>> I don't think function pointers to PETSc (DS and DM) methods are not
>> going to work in Fortran:
>>
>> ierr = PetscDSAddBoundary(prob, DM_BC_NATURAL_RIEMANN, "inflow", "Face
>> Sets", 0, 0, NULL, (void (*)(void)) PhysicsBoundary_Advect_Inflow, NULL,
>> ALEN(inflowids), inflowids, phys);CHKERRQ(ierr);
>>
>> You could write a funcs.c file that you call from your fortran code,
>> like, call setBC1(prob,...,ierr)
>>
>> and put PhysicsBoundary_Advect_Inflow and setBC1 in funcs.c, for
>> instance.
>>
>
> Wrappers for functions that that function arguments are possible, but more
> involved. We have to create an internal struct that
> holds Fortran function pointers, and then call them with the right
> arguments. This has been done for SNESSetFunction() for
> instance, so we would start emulating that.
>
> Thanks,
>
> Matt
>
>
>>
>> On Sun, Dec 13, 2020 at 5:32 AM Thibault Bridel-Bertomeu <
>> thibault.bridelbertomeu at gmail.com> wrote:
>>
>>> 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
>>>>
>>>>
>>>>
>
> --
> 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://www.cse.buffalo.edu/~knepley/
> <http://www.cse.buffalo.edu/~knepley/>
>
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