[ncl-talk] Issues with ESMF_regrid

[Rick Brownrigg]

Just to follow up on this, the message regarding max-value-size is related
to the debugger, so fixed limits within the ESMF software are likely not
the issue.

Nonetheless, the SEGV is occuring in the ESMF software and appears to be
happening in the NetCDF library, function
*netcdf_expanded.f90::nf90_get_var_2d_fourbyteint().   *For anyone else
looking into this, the line number is 1960, and a link to the current
source is:

https://github.com/Unidata/netcdf-fortran/blob/master/fortran/netcdf_expanded.f90

(I don't know what version of NetCDF ESMF may be linked against, but that
line number is in the right function).



On Tue, Oct 24, 2017 at 3:48 PM, Rick Brownrigg <brownrig at ucar.edu> wrote:

> 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.cent
>> eredPacificOceanMesh.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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>
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