[petsc-users] RAW binary write

[Sal Am]

Hi Matthew,

by raw I mean something the equivalent of pure C++ like

std::fstream fout("Vector_b.bin",std::ios::out | std::ios::binary);
fout.write((char*)&b[i],sizeof(std::complex<double>));
fout.close();  //std::vector< std::complex<double> > b

i.e. without the PETSc format information, so I can use the resulting data
in other software.

Thanks



On Thu, Nov 29, 2018 at 4:39 PM Matthew Knepley <knepley at gmail.com> wrote:

> On Thu, Nov 29, 2018 at 10:50 AM 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?
>>
>
> What is "raw binary". You have to have some format.
>
>    Matt
>
>
>> 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,
>>
>
>
> --
> 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
>
> https://www.cse.buffalo.edu/~knepley/
> <http://www.cse.buffalo.edu/~knepley/>
>
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