[petsc-users] MatView with relatively large matrix in Parallel

[Barry Smith]

   I have implemented the efficient MatView() for MPIBAIJ matrices in parallel for binary storage in petsc-dev http://www.mcs.anl.gov/petsc/petsc-as/developers/index.html with this you can save parallel MPIBAIJ matrices without first converting to AIJ format.


   Barry

On Sep 21, 2010, at 9:30 AM, Gaetan Kenway wrote:

> Hello
> 
> I am a PETSc user and have run into a problem using MatView. I am trying to output a matrix to file so I can load it instead of computing it for faster debugging. The matrix I'm trying to output is drdwt. It is a parallel block aij matrix with block size of 5. The matrix is assembled and the following code works when I run it in serial:
> 
>  call PetscViewerBinaryOpen(sumb_petsc_comm_world,drdw_name,FILE_MODE_WRITE,bin_viewer,ierr)
>  call MatView(drdwt,bin_viewer,ierr)
>  call PetscViewerDestroy(bin_viewer,ierr)
> 
> The matrix size is approximately 300k by 300k and I get an output file that is approximately 245MB in size which is expected.  However, when I run the same code in parallel on 3 processors it hangs at the MatView call until I am forced to kill the processes. I've let it go for 20 minutes with no sign of stopping.
> 
> I am not sure what is causing this.  I'm using openmpi-1.4.1  and petsc3.1 on 32 bit Ubuntu 10.10.
> 
> Thank you,
> 
> Gaetan Kenway
> 
>