[petsc-dev] Install location for MPIUNI mpi.h

[Smith, Barry F.]

> On Apr 25, 2018, at 2:47 PM, Balay, Satish <balay at mcs.anl.gov> wrote:
> 
> On Wed, 25 Apr 2018, Smith, Barry F. wrote:
> 
>> 
>> 
>>> On Apr 25, 2018, at 2:31 PM, Jed Brown <jed at jedbrown.org> wrote:
>>> 
>>> "Smith, Barry F." <bsmith at mcs.anl.gov> writes:
>>> 
>>>>> On Apr 25, 2018, at 1:36 PM, Jed Brown <jed at jedbrown.org> wrote:
>>>>> 
>>>>> It is currently installed to include/petsc/mpiuni/mpi.h and petscsys.h
>>>>> includes it as <mpi.h>, which means that users of MPIUNI need to put
>>>>> -I/prefix/include/petsc/mpiuni in their command lines.  Matt and I agree
>>>>> that this is bad.  We disagree on the solution.
>>>>> 
>>>>> He wants to install it to /prefix/include/mpi.h as though the user had
>>>>> written --download-mpich.  This would conflict if a user later installs
>>>>> a real MPI to that location.
>>>> 
>>>> Jed,
>>>> 
>>>>  So you propose in petscsys.h ?
>>>> 
>>>> #if defined(PETSC_HAVE_MPIUNI)
>>>> #include <petsc/mpiuni/mpi.h> 
>>>> #else
>>>> #include <mpi.h>
>>>> #endif
>>>> 
>>>> I don't have a problem with this.
>>> 
>>> Yes, and same installation layout as today.
>> 
>>   Ok, this is far better than copying the mpiuni mpi.h file to a public place (Matt's suggestion) and is a bit better than requiring the extra -I flag (Satish's suggestion) 
>> 
> 
> All approaches have drawbacks. This approach breaks user code. I guess thats easy to work arround [and fix these
> examples awell]
> 
> $ git grep '<mpi\.h>' |grep examples
> src/dm/examples/tests/ex42.c:#include <mpi.h>
> src/tao/leastsquares/examples/tutorials/chwirut2.c:#include <mpi.h>

  Fix these examples at the same time.
> 
> 
>>> 
>>>> I notice that the Fortran petscsys.h is scattered full of weird MPIUni specific stuff like
>>>> 
>>>> #if defined (PETSC_HAVE_MPIUNI)
>>>> #include "mpiunifdef.h"
>>>> #endif
>>>> 
>>>> #if defined(PETSC_HAVE_MPIUNI)
>>>> #define MPI_Comm PetscFortranInt
>>>> #define MPI_Group PetscFortranInt
>>>> #define PetscMPIInt PetscFortranInt
>>>> #else
>>>> #define MPI_Comm integer
>>>> #define MPI_Group integer
>>>> #define PetscMPIInt integer
>>>> #endif
> 
> I might have diverged from mpi standard to prevent '-i8' affecting petsc+mpiuni code.

   Ah, yes

> 
> Satish
> 
>>>> 
>>>> It seems PETSc Fortran does not use the standard mpif.h file? 
>>> 
>>> Yuck.
>> 
>>   I don't remember the history of this construct. There must have been a reason years ago that may no longer exist, I don't know.
>> 
>>   Barry