[petsc-users] Files saved with PetscViewerBinaryOpen - Binary file format ?

[C B]

Barry,
Thank you very much for your quick response.

The two links that you included clearly describe the formats, I have to
write a reader for another code,
so if anyone has done this in a small code, any code snippet will be
appreciated.
Cheers,

On Tue, Dec 29, 2020 at 1:15 PM Barry Smith <bsmith at petsc.dev> wrote:

>
>
> https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Vec/VecLoad.html
>  and
> https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatLoad.html define
> the simple format.
>
>   There are loaders for Matlab and Python distributed with PETSc so for
> those two languages you do not need to write your own custom loaders.
>
>   Barry
>
>
>
> On Dec 29, 2020, at 12:32 PM, C B <cebau.mail at gmail.com> wrote:
>
> Hello PETSc community !
>
> I would like to read in another code a matrix / rhs / sol  saved by PETSc.
> I am dealing with large matrices and for precision I would like to use the
> binary format.
>
> To save a matrix I am using the following lines (please let me know if I
> should make any changes), I am using an old version PETSc 2.1.5 for
> backward compatibility.
>
>  ierr =
> PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,PETSC_BINARY_CREATE,&petsc_view);CHKERRQ(ierr);
> ierr = VecView(solut,petsc_view);CHKERRQ(ierr);
> ierr = PetscViewerDestroy(petsc_view);CHKERRQ(ierr);
>
> And to save a vector:
>
> ierr = PetscViewerBinaryOpen(PETSC_COMM_WORLD, filename,
> PETSC_BINARY_CREATE, &petsc_view);CHKERRQ(ierr);
> ierr = VecView(solut, petsc_view);CHKERRQ(ierr);
> ierr = PetscViewerDestroy(petsc_view);CHKERRQ(ierr);
>
> The files are saved without any problems, and now I need to write the code
> to read the binary files.
> Please, would anyone point me to the format of these binary files and/or a
> code snippet to take as an example ?
>
> Thank you very much in advance !
> Cheers
>
>
>
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