Sanjay,
Since you are wanting ASCII output you don't need to worry about absolute
scalability. Thus what I would do is in your parallel PETSc application code
save the vectors with VecView() to binary format. Then write a stand-alone
sequential program in C, Matlab, Python that reads in the binary vectors with
VecLoad() and outputs them in any way you want. Trying to do fancy ASCII
output in parallel is not worth spending time.
Barry
On Jan 23, 2013, at 2:18 PM, "Kharche, Sanjay" <Sanjay.Kharche at
liverpool.ac.uk> wrote:
>
> Dear All
>
> I am an absolute beginner to PetSc. I am trying to output PetSc vectors in a
> specific format. This may have been discussed before, but I have so far not
> found a solution.
>
> For 2 or 3 vectors, I do this:
>
> /*
> now write it to file.
> I would like row 1 to be u, row 2 to be b, and row 3 to be u. that way I can
> use
> gnuplots surf, and also all my existin matlab code for plotting/analysis.
> */
> PetscViewer viewer; // a Petsc file pointer.
> PetscViewerASCIIOpen(PETSC_COMM_WORLD,"ubx.dat",&viewer);
> VecView(u,viewer); // this comes out with information that I dont want, and
> in a column - I need to put it as a row.
> VecView(b,viewer);
> VecView(x,viewer);
> PetscViewerDestroy( &viewer );
>
> However, I have not been able to get rid of the information about procs, and
> also the vectors u, b, and u need to be in row format as:
> 1 2 1 1 1
> 0 0 0 1 0
> -1 2 -1 0
>
> rather than what I have now:
>
> Vector Object: 1 MPI processes
> type: seq
> 1
> 2
> 1
> 1
> 1
> etc....
>
>
> Any suggestions on how to do this will be appreciated.
>
> thanks
> Sanjay
