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

[Gaetan Kenway]

  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