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?<br> <br>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?
<br> could you give me some advice? thanks a lot.<br><br>Regards,<br>Yujie<br><br><div><span class="gmail_quote">On 1/23/08, <b class="gmail_sendername">Matthew Knepley</b> <<a href="mailto:knepley@gmail.com">knepley@gmail.com
</a>> wrote:</span><blockquote class="gmail_quote" style="margin-top: 0; margin-right: 0; margin-bottom: 0; margin-left: 0; margin-left: 0.80ex; border-left-color: #cccccc; border-left-width: 1px; border-left-style: solid; padding-left: 1ex">
On Jan 22, 2008 11:01 PM, Yujie <<a href="mailto:recrusader@gmail.com">recrusader@gmail.com</a>> wrote:<br>> Dear Matt:<br>><br>> thank you for your reply. Do you have any method to generate an ascii file<br>
> of the huge sparse matrix? thanks<br><br>I think you miss my point. The PETSc function is not a bad way to generate<br>ASCII matrices. ASCII matrices make "no sense" for large operators.<br><br> Matt<br><br>
> Regards,<br>> Yujie<br>><br>><br>><br>> On 1/23/08, Matthew Knepley <<a href="mailto:knepley@gmail.com">knepley@gmail.com</a>> wrote:<br>> > On Jan 22, 2008 8:50 PM, Yujie <<a href="mailto:recrusader@gmail.com">
recrusader@gmail.com</a>> wrote:<br>> > > Hi everyone:<br>> > ><br>> > > #include "petsc.h"<br>> > > PetscErrorCode PetscViewerASCIIOpen(MPI_Comm comm,const char<br>> > > name[],PetscViewer *lab)
<br>> > ><br>> > > #include "petsc.h"<br>> > > PetscErrorCode PetscViewerBinaryOpen(MPI_Comm comm,const char<br>> > > name[],PetscFileMode type,PetscViewer *binv)<br>> > >
<br>> > > if the difference between them is that one for ASCII output and the<br>> other<br>> > > for Binary output, why are there different parameters?<br>> ><br>> > It is historical. If you want to be generic, you should use
<br>> ><br>> > PetscViewerCreate()<br>> > PetscViewerSetType()<br>> > PetscViewerFileSetMode()<br>> > PetscViewerFileSetName()<br>> ><br>> > which can create both.<br>> >
<br>> > > The speed to output matrix is very fast when I use<br>> PetscViewerBinaryOpen.<br>> > > However, when I use PetscViewerASCIIOpen, I can't get the matrix output.<br>> the<br>> > > code always is running and it has taken about one day! what's the
<br>> problem?<br>> > > thank you.<br>> ><br>> > ASCII files do not make sense for large matrices. You should use binary<br>> files.<br>> ><br>> > Matt<br>> ><br>> > > Regards,
<br>> > > Yujie<br>> > ><br>> > ><br>> > ><br>> ><br>> ><br>> ><br>> > --<br>> > What most experimenters take for granted before they begin their<br>> > experiments is infinitely more interesting than any results to which
<br>> > their experiments lead.<br>> > -- Norbert Wiener<br>> ><br>> ><br>><br>><br><br><br><br>--<br>What most experimenters take for granted before they begin their<br>experiments is infinitely more interesting than any results to which
<br>their experiments lead.<br>-- Norbert Wiener<br><br></blockquote></div><br>