[petsc-users] RAW binary write

[Sal Am]

Thank you so much Lisandro!

That was very helpful actually and what I was looking for, but now it still
requires an intermediate step of a short python script where I have to use
byteswap() on the data to get it to work on other platforms.
Would you happen to know any way of byteswapping in petsc? I was reading
and it seems PetscBinaryWrite does byteswapping but I am not sure it would
work in my case as there are no examples with it writing a petsc vector.

Thanks and all the best

On Sun, Dec 2, 2018 at 10:01 AM Lisandro Dalcin <dalcinl at gmail.com> wrote:

> Use PetscViewerBinarySetSkipHeader(viewer, PETSC_TRUE) before VecView().
>
> On Thu, 29 Nov 2018 at 18:50, Sal Am via petsc-users <
> petsc-users at mcs.anl.gov> wrote:
>
>> Is there a way to write the solution from the system Ax=b in raw binary
>> instead of PETSc binary format?
>>
>> Currently I am doing:
>>   ierr = PetscViewerBinaryOpen(PETSC_COMM_WORLD,
>> "../../python/petscpy/Vector_x_petsc.dat", FILE_MODE_WRITE,
>> &viewer);CHKERRQ(ierr);
>>   ierr = VecView(x,viewer);CHKERRQ(ierr);CHKERRQ(ierr);
>>   ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
>>
>> And then use PetscBinaryIO to read it back and save it using
>> write('newformat', 'wb') to get to raw... however this approach is not good
>> it seems as there are some troubles with little/big endian when using the
>> resulting converted file on other systems for post-processing.
>>
>> Thanks,
>>
>
>
> --
> Lisandro Dalcin
> ============
> Research Scientist
> Computer, Electrical and Mathematical Sciences & Engineering (CEMSE)
> Extreme Computing Research Center (ECRC)
> King Abdullah University of Science and Technology (KAUST)
> http://ecrc.kaust.edu.sa/
>
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