[ncl-talk] Issues with ESMF_regrid

[Rick Brownrigg]

Hi Laura,

I don't really know much about the regridding process, but what I have been
able to surmise running the script:

i) NCL reads the MPAS, and creates source*.nc and destination*.nc files.
These appear to reflect the geometry of the src/dest grids

ii) The actual regridding is is done by ESMF software, with a command:

  ESMF_RegridWeightGen --source source_grid_file.nc --destination
destination_grid_file.nc --weight
weights_onCells.15-3Mesh_to_0.15rectangular.nc --src_type ESMF -i

This program SEGVs almost immediately, with a message:

"values=<error reading variable: value requires 155713536 bytes, which is
more than max-value-size>...."

That value is exactly the size of one of the variables in the source*.nc
file.  So it looks like some internal limit is being exceeded in the ESMF
software.

Is this one of the larger MPAS files you've attempted to regrid?  I wonder
if anyone else can comment on this?  Those on the glade file system can see
all the relevant files under /glade/scratch/brownrig

I'm not sure what to tell you as a work-around. Without a debug version of
the code, its nearly impossible for me to tell much more or to  detemine
what the limits might be. Wish I had a better answer.

Rick



On Tue, Oct 24, 2017 at 10:13 AM, Laura Fowler <laura at ucar.edu> wrote:

> Hi:
>
> I am trying to regrid an MPAS unstructured mesh to a rectangular mesh
> on cheyenne using ncl/6.4.0. My script crashes with a SIGSEGV and I am
> not understanding where this comes from. I have done this successfully
> in the past but do not see what I am doing wrong right now, but I
> recall that it was with an ealier version of ncl. I am attaching the
> output of my script in regrid.to_rectMesh.out.
>
> The script itself can be found in
> /glade2/scratch2/laura/MPAS.PacificOcean/initialization.
> centeredPacificOceanMesh.15-3km/regrid.to_rectMesh.ncl.
> I also tried to regrid the same MPAS mesh to an other unstructured
> mesh and got a similar SIGSEGV (see regrid.to_2621442Mesh.ncl), so I
> assume that the errors are the same.
>
> Hope you can help me figure this one out.
> Thanks,
> Laura
>
>
> --
> !-----------------------------------------------------------
> --------------------------------------------------
> Laura D. Fowler
> Mesoscale and Microscale Meteorology Division (MMM)
> National Center for Atmospheric Research
> P.O. Box 3000, Boulder CO 80307-3000
>
> e-mail: laura at ucar.edu
> phone: 303-497-1628
>
> !-----------------------------------------------------------
> --------------------------------------------------
>
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