[petsc-users] Ignore command line arguments with fortran code using PETSc

[Tim Steinhoff]

2016-07-27 21:42 GMT+02:00 Barry Smith <bsmith at mcs.anl.gov>:
>
>   Actually there is currently no way to PetscInitialize from Fortran without adding the command line options to the database. In the middle
> of petscinitialize_() is the code fragment
>
>   PETScParseFortranArgs_Private(&PetscGlobalArgc,&PetscGlobalArgs);
>   FIXCHAR(filename,len,t1);
>   *ierr = PetscOptionsInsert(NULL,&PetscGlobalArgc,&PetscGlobalArgs,t1);
>
>   We'll need to do a bit of code refactoring to provide a Fortran petscinitializenoarguments_(). The simplest way to refactor would be to change the name of petscinitialize_ to say PetscInitializeFortran_Internal() and add a bool argument whether to process the arguments and then write two trivial routines petscinitialize_ that calls the new routine with PETSC_TRUE and petscinitializenoarguments_() that calls it with PETSC_FALSE.

Thanks Barry. It would be really nice if PETSc comes with that feature
in future, because I would prefer not to make any changes to the PETSc
code that disappear with every new PETSc release.

>
>    Barry
>
>   Of course you can have a C/C++ main routine that calls PetscInitializeNoArguments(); followed by PetscInitializeFortran() and then have the bulk of your code in Fortran.
That would work, but we have a rather large fortran code without any
C. So, for now we will probably stick to your first approach and keep
our code fotran only.

Thanks again,
Volker


>
>
>> On Jul 27, 2016, at 10:55 AM, Tim Steinhoff <kandanovian at gmail.com> wrote:
>>
>> 2016-07-27 16:04 GMT+02:00 Matthew Knepley <knepley at gmail.com>:
>>> On Wed, Jul 27, 2016 at 4:59 AM, Tim Steinhoff <kandanovian at gmail.com>
>>> wrote:
>>>>
>>>> Hi all,
>>>>
>>>> we coupled PETSc with our fortran code. Is there any way to let PETSc
>>>> (PetscInitialize) ignore all arguments passed by the command line?
>>>> Since our code is controlled by command line arguements as well, it
>>>> leads to a mess, when those arguments are read twice.
>>>
>>>
>>> 1) You can use PetscInitializeNoArguments()
>>
>> Thanks! I thought that function was for C/C++ only.
>>
>>>
>>> 2) What goes wrong? PETSc should just ignore any options it does not
>>> recognize.
>>
>>
>> The problem is that our code uses the same or similar argument names
>> as PETSc does and our end user should not have access to all petsc
>> options.
>>
>>
>>>
>>>  Thanks,
>>>
>>>    Matt
>>>
>>>>
>>>> Thanks and kind regards,
>>>>
>>>> Volker
>>>
>>>
>>>
>>>
>>> --
>>> 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
>