[mpas-developers] Vector Reconstruction

Wed Mar 24 15:00:41 MDT 2010

Hi Michael,

I'm able to reproduce your results.  It doesn't look good!  I'll see what
I can figure out.

-Xylar

> Hi, Todd.
>
> I wonder whether there's something odd with how I've added the new
> module_vector_reconstruction.F code and Registry entry. I had been
> testing with branches/swmodel for simplicity, and the changes are
> really trivial. If you wouldn't mind, could you give a try with
> the tar file I've been testing with? I've placed this at
> http://www.mmm.ucar.edu/people/duda/files/swmodel_vectors.tar.gz.
> The namelist is set up to run just 5 time steps, and the input
> files are all included, so it should just be a matter of compiling
> and running. Also included in the tar file is the output file that
> I generated for SWTC2; doing an ncdump or using ncview, you can
> see the large values in uReconstructZ.
>
> If you're able to get correct results with my tar file, I'd not
> object to committing the new module_vector_reconstruction.F; I can
> propose to add this in a new shared directory 'operators', to be
> created in trunk/mpas/src with appropriate changes to the
> Makefiles. However, if you can reproduce the large values of
> uReconstructZ with my tar file, I can look for any differences if
> you could supply the code that you were able to successfully run
> with. Does that sound like a reasonable way forward?
>
> Cheers,
> Michael
>
>
> On Wed, Mar 24, 2010 at 12:06:19PM -0600, Todd Ringler wrote:
>>
>> Hi Michael,
>>
>> I can not reproduce your finding. Below is the rbf reconstruction
>> (vectors) and z-component of velocity (colors with colorbar, units m/
>> s). This is SWTC#2 on the quasi-uniform 2562 grid. I am happy to
>> followup over the phone. Have to run, back at 2 pm.
>>
>> Cheers,
>> Todd
>>
>
>
>
>>
>> On Mar 23, 2010, at 11:56 AM, Michael Duda wrote:
>>
>> >Hi, Xylar.
>> >
>> >Thanks for the quick reply. In SWTC2, the maximum zonal velocity
>> >is around 38 m/s at the equator, so 10 m/s for uReconstructZ does
>> >seem out of place. Just to make sure I understand how to interpret
>> >uReconstruct{X,Y,Z}, these are the components of the velocity
>> >vector in Cartesian space, with the z-axis positive through the
>> >north pole of the sphere, right? I had been testing on a fairly
>> >coarse grid (10242 cells), so that could be a factor; I'll do a
>> >little more testing at higher resolution.
>> >
>> >Cheers,
>> >Michael
>> >
>> >
>> >On Tue, Mar 23, 2010 at 11:41:18AM -0600, Xylar S. Asay-Davis wrote:
>> >>Hi Michael,
>> >>
>> >>I don't think your attachment made it through.
>> >>
>> >>I'll take a look at shallow water test case 2 to see what might be
>> >>the
>> >>problem there. The value of uReconstructZ won't machine zero for a
>> >>purely
>> >>zonal flow because the reconstruction in its current form will only
>> >>guarantee exact reconstruct of a constant flow in the tangent plane
>> >>of the
>> >>cell, where as a zonal flow has components slightly out of the
>> >>tangent
>> >>plane.  In my tests, I was seeing uReconstructZ smaller than
>> >>uReconstructX
>> >>and uReconstructY by a factor of around 1e-6.
>> >>
>> >>-Xylar
>> >>
>> >>
>> >>>Hi, Xylar.
>> >>>
>> >>>The module looks good to me -- very clean code. The only changes
>> >>>I'd suggest are to the comments at the beginning of the
>> >>>init_reconstruct() routine, and a few changes to indentation, as
>> >>>in the attached module_vector_reconstruction.F.
>> >>>
>> >>>This is most likely a problem in how I'm performing the
>> >>>computation given that both you and Todd have checked the
>> >>>reconstructed vectors, but I'm having trouble getting a zonal and
>> >>>meridional wind from the reconstructed vector in (x,y,z). Even
>> >>>plotting the magnitude of the reconstructed vector, sqrt(x^2 + y^2
>> >>>+ z^2), I'm getting some unexpected values in the reconstructed
>> >>>wind speed field for shallow water test case 2 (with alpha=0).
>> >>>Given that we should have purely zonal flow for this test case,
>> >>>I'm suprised to see values in uReconstructZ of order 10. Do either
>> >>>you or Todd have any thoughts or suggestions?
>> >>>
>> >>>Cheers,
>> >>>Michael
>> >>>
>> >>>
>> >>>On Mon, Mar 22, 2010 at 03:30:39PM -0600, Xylar S. Asay-Davis wrote:
>> >>>>Attached is my proposed vector reconstruction code.  I have run
>> >>>>several
>> >>>>sanity checks and it seems to work fine.  However, I haven't been
>> >>>>able
>> >>>>to
>> >>>>get a full ocean core run with this code.  It is not clear to me
>> >>>>if this
>> >>>>has to do with this code or with recent changes that Mark has
>> >>>>made to
>> >>>>the
>> >>>>ocean core relating to 3D density.  I'll keep working with Mark
>> >>>>to try
>> >>>>to
>> >>>>figure that out, but in the mean time it would be great to have
>> >>>>Todd
>> >>>>and/or Michael test out this code to see if it will work for you.
>> >>>>
>> >>>>A registry entry for the coeffs_reconst is required as follows
>> >>>>(already
>> >>>>in
>> >>>>the ocean core):
>> >>>>var real    coeffs_reconstruct ( R3 maxEdges nCells ) -
>> >>>>coeffs_reconstruct
>> >>>>- -
>> >>>>
>> >>>>Registry entries for  matrix_reconstruct, normal and  rbf_value
>> >>>>are no
>> >>>>longer required by this code.
>> >>>>
>> >>>>-Xylar
>> >>>
>> >>>>_______________________________________________
>> >>>>mpas-developers mailing list
>> >>>>mpas-developers at mailman.ucar.edu
>> >>>>http://mailman.ucar.edu/mailman/listinfo/mpas-developers
>> >>>
>> >>>_______________________________________________
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>> >>>
>> >>
>> >>
>> >>***********************
>> >>Xylar S. Asay-Davis
>> >>E-mail: xylar at lanl.gov
>> >>Phone: (505) 606-0025
>> >>Fax: (505) 665-2659
>> >>CNLS, MS B258
>> >>Los Alamos National Laboratory
>> >>Los Alamos, NM 87545
>> >>***********************
>> >>
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>>
>
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***********************
Xylar S. Asay-Davis
E-mail: xylar at lanl.gov
Phone: (505) 606-0025
Fax: (505) 665-2659
CNLS, MS B258
Los Alamos National Laboratory
Los Alamos, NM 87545
***********************