WRF driver layer routine: module_tiles: set_tiles
examples
There are two forms of the set_tiles subroutine.
The first, shown in examples 1-3, takes 9 arguments and is used to specify
an interior region of a domain. This is done by specifying the domain indices
(ids, ide, jds, jde) of the extent of the region to be tiled. Note that
the tile boundaries do not change within the interior; rather set_tiles
removes the appropriate cells from the tiles containing parts of the boundary.
The number of tiles used (in this case, 4) is determined by the namelist
or the environment. This form of set_tiles can also be used to specify
computation out onto the patch halo (last four arguments; no examples shown
on this page).
The second form of the set_tiles subroutine takes
6 arguments, and is used to specify a computation that only occurs on the
boundaries (examples 4-6). The second through fifth arguments are the domain
indices of the extent of the region and the sixth argument is the number
of cells in the boundary to be computed. Note that this form of set_tiles
always uses four tiles.
Set tiles returns the number of tiles as grid%num_tiles.
The ranges for the tiles are returned in the integer arrays grid%i_start,
grid%i_end, grid%j_start, and grid%j_end, each of which is dimensioned
with grid%num_tiles elements.
All of the examples below assume the grid is decomposed
over a single patch; however, the algorithm will work properly for multiple
patches. The colors in the diagrams below represent tile number (indicated
in legend for each plot).
1. Set tiles to cover entire domain
CALL set_tiles ( grid , ids , ide , jds , jde
, ips , ipe , jps , jpe )
legend: blue = tile 0, blue-green = tile 1, yellow-green = tile 2, red
= tile 3
2. Set tiles to cover interior of mass points except 1-boundary
CALL set_tiles ( grid , ids+1 , ide-2 , jds+1 , jde-2 , ips , ipe ,
jps , jpe )
legend: light-blue = tile 0, yellow-green = tile 1, orange(ish) = tile
2, red = tile 3
3. Set tiles to cover interior 2-boundary on E/S and 1 boundary N/W
CALL set_tiles ( grid , ids+2 , ide-1 , jds+2 , jde-1 , ips , ipe ,
jps , jpe )
legend: light-blue = tile 0, yellow-green = tile 1, orange(ish) = tile
2, red = tile 3
4. Set tiles to compute only the 1-boundary
CALL set_tiles ( grid , ids , ide , jds , jde , 1 )
legend: light-blue = tile 0, yellow-green = tile 1, orange(ish) = tile
2, red = tile 3
5. Set tiles to compute only the 2-boundary
CALL set_tiles ( grid , ids , ide , jds , jde , 2 )
legend: light-blue = tile 0, yellow-green = tile 1, orange(ish) = tile
2, red = tile 3
6. Set tiles to compute 2-boundary on mass grid
CALL set_tiles ( grid , ids , ide-1 , jds , jde-1 , 2 )
legend: light-blue = tile 0, yellow-green = tile 1, orange(ish) = tile
2, red = tile 3
Created September 8, 2000
John Michalakes
michalak@ucar.edu