Recent inconsistencies with Pnetcdf and MPI

[Jim Edwards]

Hi Divyanshu,

>From your description it sounds like the file written is corrupted?  And
when you say "The error also doesn't appear when I use fewer processes on a
single node on the cluster."   Do you
mean use fewer processes to write the file or to read the file?  It really
sounds to me like an application problem and not a pnetcdf or mpi issue.  I
think that you may need to provide
an exact description of how the problem is created including the system you
are using, the mpi library and version as well as the pnetcdf version and
the application.

Jim

On Fri, Jul 11, 2025 at 4:13 PM Divyanshu Gola <divyans at umich.edu> wrote:

> Hi, This is a shot in the dark but I thought why not.   The exact same
> code that I had been using until a few weeks ago gives me an error when I
> am trying to read restart files using PNetcdf. The error is Index exceeds
> dimension bounds, or Start+Count
> ZjQcmQRYFpfptBannerStart
> This Message Is From an External Sender
> This message came from outside your organization.
>
> ZjQcmQRYFpfptBannerEnd
> Hi,
>
> This is a shot in the dark but I thought why not.
>
> The exact same code that I had been using until a few weeks ago gives me
> an error when I am trying to read restart files using PNetcdf. The error is *Index
> exceeds dimension bounds, or Start+Count exceeds dimension bounds. *Based
> on days of debugging, I have narrowed it down to some problem during the
> writing of the restart files (and not the reading itself). All of these
> errors seem to originate from the way PNetcdf is built and the MPI file
> system used on the cluster (because I can run the same code on a different
> cluster), but I can't seem to identify the root cause. The error also
> doesn't appear when I use fewer processes on a single node on the cluster.
>
> I know this is most likely not a bug in the PNetcdf library but something
> else, but I was wondering if people on this mailing list have encountered a
> similar issue.
>
> Apologies for the long email and thanks
>
> Divyanshu
>
> Postdoctoral Researcher
> University of Michigan
>


-- 
Jim Edwards
STAND UP FOR SCIENCE
CESM Software Engineer
National Center for Atmospheric Research
Boulder, CO
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/parallel-netcdf/attachments/20250711/1569f184/attachment.html>