what's the difference between PetscViewerASCIIOpen() and PetscViewerBinaryOpen()?

[Yujie]

Thank you for your further explanation. I just want to use this data in
other packages. I think that ASCII file is likely
better. Because I don't know the format of the binary file? how to find it?

In addition, do you have any better methods to save the sparsity structure
picture
of the matrix? Now, I use "-mat_view_draw" to do this. However, the
speed is very slow and the picture is small. I want to get a big
picture and directly save it to the disk?
could you give me some advice? thanks a lot.

Regards,
Yujie

On 1/23/08, Matthew Knepley <knepley at gmail.com> wrote:
>
> On Jan 22, 2008 11:01 PM, Yujie <recrusader at gmail.com> wrote:
> > Dear Matt:
> >
> > thank you for your reply. Do you have any method to generate an ascii
> file
> > of the huge sparse matrix? thanks
>
> I think you miss my point. The PETSc function is not a bad way to generate
> ASCII matrices. ASCII matrices make "no sense" for large operators.
>
>    Matt
>
> > Regards,
> > Yujie
> >
> >
> >
> > On 1/23/08, Matthew Knepley <knepley at gmail.com> wrote:
> > > On Jan 22, 2008 8:50 PM, Yujie <recrusader at gmail.com> wrote:
> > > > Hi everyone:
> > > >
> > > > #include "petsc.h"
> > > >  PetscErrorCode PetscViewerASCIIOpen(MPI_Comm comm,const char
> > > > name[],PetscViewer *lab)
> > > >
> > > > #include "petsc.h"
> > > >  PetscErrorCode PetscViewerBinaryOpen(MPI_Comm comm,const char
> > > > name[],PetscFileMode type,PetscViewer *binv)
> > > >
> > > > if the difference between them is that one for ASCII output and the
> > other
> > > > for Binary output, why are there different parameters?
> > >
> > > It is historical. If you want to be generic, you should use
> > >
> > >   PetscViewerCreate()
> > >   PetscViewerSetType()
> > >   PetscViewerFileSetMode()
> > >   PetscViewerFileSetName()
> > >
> > > which can create both.
> > >
> > > > The speed to output matrix is very fast when I use
> > PetscViewerBinaryOpen.
> > > > However, when I use PetscViewerASCIIOpen, I can't get the matrix
> output.
> > the
> > > > code always is running and it has taken about one day! what's the
> > problem?
> > > > thank you.
> > >
> > > ASCII files do not make sense for large matrices. You should use
> binary
> > files.
> > >
> > >    Matt
> > >
> > > > Regards,
> > > > Yujie
> > > >
> > > >
> > > >
> > >
> > >
> > >
> > > --
> > > 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
> > >
> > >
> >
> >
>
>
>
> --
> 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
>
>
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