[MITgcm-support] defining my own xx_gentim2d_weight file

[Daniel Goldberg]

Hi Gael

I have asked about the xx_gentim2d_weight and xx_genarr2d_weight files
before, but that was because I wanted not to define them. Now, however, I
would like to actually use them to weight the gradient data when packing
for M1QN3.

I might have misunderstood their purpose before. My understanding is that
if I use the genarr2d control with size=2, then i would define in data.ctrl:

xx_genarr2d_weight='weightfile1','weightfile2'

and then in the run directory i would provide binary files weightfile1.bin
and weightfile2.bin. These binary files would be the size of the grid, and
would contain the weight I want to attach to the corresponding gradient
entry.

however, while these files are read, I am finding this is not the case --
and I'm not sure if I understand the point of the xx_genarr2d_weight
parameter array -- or else I'm not sure I am constructing the binary files
correctly.

for instance, say my grid is Nx=100,Ny=100. For genarr2d control #1, I
would like to weight the gradient by 2x for i.le.50, and by 0.5x for
i.gt.50. My understanding is that I would create a file via

q=zeros(100,100); q(1:50,:) = 2; q(51:100,:)=0.5;
fid=fopen('weightfile1.bin','w','b'); fwrite(fid,q,'real*8'); fclose(fid);

and then place weightfile1.bin in the run directory. However, by inspection
of ctrl_set_xy_pack.F, I can see that the weightFld2D array does not
populate with the values I would expect, and I am not sure why.

Is there an example in verification/ of a weighttype being used, with an
nonconstant weight field being set via file?

Many thanks
Dan

-- 

Daniel Goldberg, PhD
Lecturer in Glaciology
School of Geosciences, University of Edinburgh
Geography Building, Drummond Street, Edinburgh EH8 9XP


em: D <dgoldber at mit.edu>an.Goldberg at ed.ac.uk
web: http://ocean.mit.edu/~dgoldberg
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