[petsc-users] Petsc + nvhpc

[Junchao Zhang]

Hi, Herbert,
   I don't have much experience on OpenACC and PETSc CI doesn't have such
tests.  Could you avoid using nvfortran and instead use gfortran to compile
your Fortran + OpenACC code?  If you, then you can use the latest petsc
code and make our debugging easier.
   Also, could you provide us with a test and instructions to reproduce the
problem?

   Thanks!
--Junchao Zhang


On Thu, Oct 16, 2025 at 5:07 AM howen via petsc-users <
petsc-users at mcs.anl.gov> wrote:

> Dear All,
>
> I am interfacing our CFD code (Fortran + OpenACC)  to Petsc.
> Since we use OpenACC the natural choice for us is to use Nvidia´s nvhpc
> compiler. The Gnu compiler does not work well and we do not have access to
> the Cray compiler.
>
> I already know that the latest version of Petsc does not compile with
> nvhpc, I am therefore using version 3.21.
> I get good results on the CPU both in serial and parallel (MPI). However,
> the GPU implementation, that is what we are interested in, only work
> correctly for the serial version. In parallel, the results are different.
> Even for a CG solve.
>
> I would like to know, if you have experience with the Nvidia compiler.  I
> am particularly interested if you have already observed issues with it.
> Your opinion on whether to put further effort into trying to find a bug I
> may have introduced during the interfacing is highly appreciated.
>
> Best,
>
> Herbert Owen
> Senior Researcher, Dpt. Computer Applications in Science and Engineering
> Barcelona Supercomputing Center (BSC-CNS)
> Tel: +34 93 413 4038
> Skype: herbert.owen
>
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