Re: Comparing matrices between 2 different codes and viewing of matrix

[Barry Smith <bsmith@xxxxxxxxxxx>]

   You use EITHER PetscViewerCreate() and PetscViewerSetType() and  
PetscViewerFileSetName() OR PetscViewerASCIIOpen()
so use


> call PetscViewerASCIIOpen(MPI_COMM_WORLD, "matrix.txt",viewer,ierr)
> > call MatView(A_mat_uv,viewer,ierr)
> call PetscViewerDestroy(viewer,ierr)



On May 27, 2008, at 5:57 AM, Ben Tay wrote:

> Hi Barry,
>
> Thanks for pointing out. However, I only got a 0 byte file after  
> adding the include statement.
>
> I am programming in parallel and my matrix is created using  
> MatCreateMPIAIJ. Did I missed out some commands?
>
> PetscViewer viewer
>
>
> ...
>
> call  PetscViewerCreate(MPI_COMM_WORLD,viewer,ierr)
>
> call MatView(A_mat_uv,viewer,ierr)
>
> call PetscViewerASCIIOpen(MPI_COMM_WORLD, "matrix.txt",viewer,ierr)
>
> call PetscViewerDestroy(viewer,ierr)
>
> Thank you very much.
>
> Regards.
>
>
> Barry Smith wrote:
> >   Likely you forgot to #include "finclude/petscviewer.h" in the  
> > Fortran subroutine that
> > is doing this stuff.
> >
> >
> > On May 25, 2008, at 5:43 AM, Ben Tay wrote:
> >
> > > Hi,
> > >
> > > I have an old serial code and a newer parallel code. The new  
> > > parallel code is converted from the old serial code. However, due  
> > > to numerous changes, the answers from the new code now differs  
> > > from the old one after the 1st step. What is the best way to  
> > > compare the matrices from the 2 different code?
> > >
> > > I guess the most direct mtd is to use MatView to store the matrix  
> > > in a ACSII file and spot the difference between the 2 files.  
> > > However, I can't seem to get it right. What I did is:
> > >
> > > PetscViewer viewer
> > >
> > > call  PetscViewerCreate(PETSC_COMM_SELF,viewer,ierr)
> > >
> > > call MatView(A_mat_uv,viewer,ierr)
> > >
> > > call PetscViewerDestroy(viewer,ierr)
> > >
> > > call PetscViewerASCIIOpen(PETSC_COMM_SELF, "matrix.txt",viewer,ierr)
> > >
> > > However, I get the error that "PetscViewer viewer" has syntax  
> > > error. Hope you can help me out.
> > >
> > > Thank you very much.
> > >
> > > Regards