On Jul 21, 2014, at 8:41 AM, Jed Brown <[email protected]> wrote:
> Matthew Knepley <[email protected]> writes:
>
>> On Jul 21, 2014 5:44 AM, "Stephen Wornom" <[email protected]> wrote:
>>>
>>> I have an unstructured mesh code used to compute vortex shedding problems
>> saving the solutions every 500-1000 time steps. The mesh size is 3 to 20
>> MNodes. The minimum number of cores that I us is 128 for the 3MNode mesh.
>>> I would like to know if PETSC could be used to use to save the solutions
>> using MPI-IO?
>>
>> The normal VecView() for the binary viewer will use MPI/IO.
>
> You need -viewer_binary_mpiio or PetscViewerBinarySetMPIIO().
We should change this to use a PetscViewerFormat instead of special casing
it.
>
> PETSc devs, do you suppose MPI-IO support is stable enough that we could
> make this a default?
It is not so much a question of stability, it is more a question of (I
believe) MPI IO is just loads slower for what might normal PETSc users use, it
only pays off for large numbers of nodes.
Barry
> In any case, PetscViewerBinarySetMPIIO should take
> a PetscBool.
