Hi Keita,

I am afraid that I do not have direct access to the machine in question nor do 
I have a line of communication to the administrative team. I do not envisage 
there being issues with -eps_monitor in standard usage. However I am creating a 
new communicator and using this. I have encountered problems in the past with 
options like -mat_view_matrix when using a communicator other than 
PETSC_COMM_WORLD. I think the fact that this happens for -eps_monitor on the XT 
and not on the other platforms I tried is down to differences in the MPI 
implementation present and not any fault with the system.

Regards,

Niall.  

On 29 Jul 2010, at 17:11, Keita Teranishi wrote:

> Niall,
> 
> Please report your problem to the system administrator of the machine you are 
> using.  I am interested in why PETSc fails with -eps_monitor on XT.
> 
> Thanks,
> ================================
>  Keita Teranishi
>  Scientific Library Group
>  Cray, Inc.
>  keita at cray.com
> ================================
> 
> 
> -----Original Message-----
> From: petsc-users-bounces at mcs.anl.gov [mailto:petsc-users-bounces at 
> mcs.anl.gov] On Behalf Of Niall Moran
> Sent: Thursday, July 29, 2010 8:45 AM
> To: PETSc users list
> Subject: Re: [petsc-users] MPI_Attr_delete from MatDestroy
> 
> On 29 Jul 2010, at 14:37, Jose E. Roman wrote:
>>> I am getting some errors from a code that uses PETSc and SLEPc to 
>>> diagonalise matrices in parallel. The code has been working fine on many 
>>> machines but is giving problems on a Cray XT4 machine. The PETSc sparse 
>>> matrix type MPIAIJ is used to store the matrix and then the SLEPc 
>>> Krylov-Schur solver is used to iteratively diagonalise. For each run the 
>>> dimension of the matrices diagonalised can vary wildly from tens or 
>>> hundreds of rows to hundreds of millions of rows. Even though the smaller 
>>> matrices can be computed easily on a single core I wanted to be able to 
>>> perform all calculations from a single run. When running on thousands of 
>>> processors SLEPc does not like it when you have more cores than rows in the 
>>> matrix.
>> 
>> In slepc-dev I have made a fix for the case when the number of rows assigned 
>> to one of the processes is zero. In slepc-3.0.0 I don't see this problem.
>> Jose
> 
> Thanks for making me aware of this Jose. I no longer need to create my own 
> communicators. I have also realised that the runs that were failing with this 
> message were using the -eps_monitor argument. So not using this argument 
> solves the problem as well. This argument did not make any difference on 
> other platforms though.
> 
> Niall. 

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