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Next: 6.18.4 exch2, SIZE.h, and
Up: 6.18 exch2: Extended Cubed
Previous: 6.18.2 Invoking exch2
Contents
6.18.3 Generating Topology Files for exch2
Alternate cubed sphere topologies may be created using the Matlab
scripts in utils/exch2/matlab-topology-generator. Running the
m-file
driver.m
from the Matlab prompt (there are no parameters to pass) generates
exch2 topology files W2_EXCH2_TOPOLOGY.h and
w2_e2setup.F in the working directory and displays a figure of
the topology via Matlab - figures 6.6, 6.5,
and 6.4 are examples of the generated diagrams. The other
m-files in the directory are
subroutines called from driver.m and should not be run ``bare'' except
for development purposes.
The parameters that determine the dimensions and topology of the
generated configuration are nr, nb, ng,
tnx and tny, and all are assigned early in the script.
The first three determine the height and width of the subdomains and
hence the size of the overall domain. Each one determines the number
of grid points, and therefore the resolution, along the subdomain
sides in a ``great circle'' around each the three spatial axes of the cube. At the time
of this writing MITgcm requires these three parameters to be equal,
but they provide for future releases to accomodate different
resolutions around the axes to allow subdomains with differing resolutions.
The parameters tnx and tny determine the width and height of
the tiles into which the subdomains are decomposed, and must evenly
divide the integer assigned to nr, nb and ng.
The result is a rectangular tiling of the subdomain. Figure
6.4 shows one possible topology for a twenty-four-tile
cube, and figure 6.5 shows one for twelve tiles.
Figure 6.4:
Plot of a cubed sphere topology with a 32192 domain
divided into six 3232 subdomains, each of which is divided
into four tiles of width tnx=16 and height tny=16 for a
total of twenty-four tiles. The colored borders of the subdomains
represent the parameters nr (red), nb (blue), and
ng (green).
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Figure 6.5:
Plot of a cubed sphere topology with a 32192 domain
divided into six 3232 subdomains of two tiles each
(tnx=16, tny=32).
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Figure 6.6:
Plot of a cubed sphere topology with a 32192 domain
divided into six 3232 subdomains with one tile each
(tnx=32, tny=32). This is the default configuration.
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Tiles can be selected from the topology to be omitted from being
allocated memory and processors. This tuning is useful in ocean
modeling for omitting tiles that fall entirely on land. The tiles
omitted are specified in the file
blanklist.txt
by their tile number in the topology, separated by a newline.
Next: 6.18.4 exch2, SIZE.h, and
Up: 6.18 exch2: Extended Cubed
Previous: 6.18.2 Invoking exch2
Contents
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