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

[Barry Smith]

> On Jul 28, 2016, at 2:35 AM, Tim Steinhoff <kandanovian at gmail.com> wrote:
> 
> 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.

   Understood. You could make a pull request with your changes https://bitbucket.org/petsc/petsc/wiki/pull-request-instructions-git otherwise I will add it but it will take a few days since I am backlogged.

   Barry

> 
>> 
>>   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
>>