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C $Header: /u/gcmpack/MITgcm/model/src/ini_spherical_polar_grid.F,v 1.27 2010/04/17 18:25:12 jmc Exp $ |
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C $Name: $ |
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|
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#include "PACKAGES_CONFIG.h" |
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#include "CPP_OPTIONS.h" |
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#ifdef ALLOW_EXCH2 |
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# include "W2_OPTIONS.h" |
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#endif /* ALLOW_EXCH2 */ |
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|
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CBOP |
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C !ROUTINE: INI_LOCAL_GRID |
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C !INTERFACE: |
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SUBROUTINE INI_LOCAL_GRID( |
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O xGloc, yGloc, |
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O delXloc, delYloc, |
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O gridNx, gridNy, |
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I bi, bj, myThid ) |
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|
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C !DESCRIPTION: \bv |
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C *==========================================================* |
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C | SUBROUTINE INI_LOCAL_GRID |
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C | o Initialise model tile-local horizontal grid |
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C *==========================================================* |
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C | Set local grid-point location (xGloc & yGloc) and |
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C | local grid-point spacing (delXloc,delYloc) keeping the |
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C | same units as grid-spacing input parameter (delX,delY |
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C | and xgOrigin,ygOrigin). |
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C | This tile-local mesh setting will be used to build |
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C | the horizontal model grid, according to the selected |
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C | grid option (cartesian, spherical_polar or cylindrical) |
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C *==========================================================* |
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C \ev |
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|
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C !USES: |
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IMPLICIT NONE |
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C === Global variables === |
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#include "SIZE.h" |
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#include "EEPARAMS.h" |
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#include "PARAMS.h" |
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#ifdef ALLOW_EXCH2 |
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# include "W2_EXCH2_SIZE.h" |
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# include "W2_EXCH2_TOPOLOGY.h" |
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#endif /* ALLOW_EXCH2 */ |
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#include "SET_GRID.h" |
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|
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C !INPUT/OUTPUT PARAMETERS: |
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C == Routine arguments == |
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C xGloc :: mesh corner-point location (local "Long" real array type) |
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C yGloc :: mesh corner-point location (local "Long" real array type) |
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C delXloc :: mesh spacing in X direction |
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C delYloc :: mesh spacing in Y direction |
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C gridNx :: mesh total grid-point number in X direction |
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C gridNy :: mesh total grid-point number in Y direction |
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C bi, bj :: tile indices |
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C myThid :: my Thread Id Number |
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|
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C NOTICE the extended range of indices!! |
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_RL xGloc(1-OLx:sNx+OLx+1,1-OLy:sNy+OLy+1) |
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_RL yGloc(1-OLx:sNx+OLx+1,1-OLy:sNy+OLy+1) |
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C NOTICE the extended range of indices!! |
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_RL delXloc(0-OLx:sNx+OLx) |
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_RL delYloc(0-OLy:sNy+OLy) |
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INTEGER gridNx, gridNy |
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INTEGER bi, bj |
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INTEGER myThid |
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|
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C !LOCAL VARIABLES: |
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C == Local variables == |
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C xG0,yG0 :: coordinate of South-West tile-corner |
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C iG0,jG0 :: Tile base X and Y indices within global index space |
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C i, j :: loop counters |
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INTEGER iG0, jG0 |
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INTEGER i, j |
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_RL xG0, yG0 |
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#ifdef ALLOW_EXCH2 |
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INTEGER tN |
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#endif /* ALLOW_EXCH2 */ |
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|
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C The functions iGl, jGl return the "global" index with valid values beyond |
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C halo regions |
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C cnh wrote: |
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C > I dont understand why we would ever have to multiply the |
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C > overlap by the total domain size e.g |
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C > OLx*Nx, OLy*Ny. |
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C > Can anybody explain? Lines are in ini_spherical_polar_grid.F. |
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C > Surprised the code works if its wrong, so I am puzzled. |
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C jmc replied: |
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C Yes, I can explain this since I put this modification to work |
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C with small domain (where OLy > Ny, as for instance, zonal-average |
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C case): |
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C This has no effect on the acuracy of the evaluation of iGl(I,bi) |
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C and jGl(j,bj) since we take mod(a+OLx*Nx,Nx) and mod(b+OLy*Ny,Ny). |
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C But in case a or b is negative, then the FORTRAN function "mod" |
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C does not return the matematical value of the "modulus" function, |
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C and this is not good for your purpose. |
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C This is why I add +OLx*Nx and +OLy*Ny to be sure that the 1rst |
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C argument of the mod function is positive. |
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c INTEGER iGl,jGl |
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c iGl(i,bi) = 1+MOD(iG0+i-1+OLx*gridNx,gridNx) |
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c jGl(j,bj) = 1+MOD(jG0+j-1+OLy*gridNy,gridNy) |
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CEOP |
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|
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#ifdef ALLOW_EXCH2 |
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gridNx = exch2_mydNx(1) |
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gridNy = exch2_mydNy(1) |
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#else /* ALLOW_EXCH2 */ |
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gridNx = Nx |
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gridNy = Ny |
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#endif /* ALLOW_EXCH2 */ |
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|
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c DO bj = myByLo(myThid), myByHi(myThid) |
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c DO bi = myBxLo(myThid), myBxHi(myThid) |
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C For this tile ... |
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|
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C-- Set current tile base X and base Y indices within global index space |
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C e.g., local indices of tile south-west corner grid point are (1,1) |
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C and global indices are 1+iG0, 1+jG0 |
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#ifdef ALLOW_EXCH2 |
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tN = W2_myTileList(bi,bj) |
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iG0 = exch2_tBasex(tN) |
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jG0 = exch2_tBasey(tN) |
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#else /* ALLOW_EXCH2 */ |
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iG0 = myXGlobalLo - 1 + (bi-1)*sNx |
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jG0 = myYGlobalLo - 1 + (bj-1)*sNy |
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#endif /* ALLOW_EXCH2 */ |
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|
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C-- First find coordinate of tile corner (meaning outer corner of halo) |
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xG0 = xgOrigin |
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C Find the X-coordinate of the outer grid-line of the "real" tile |
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DO i=1, iG0 |
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xG0 = xG0 + delX(i) |
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ENDDO |
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C Back-step to the outer grid-line of the "halo" region |
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DO i=1, OLx |
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xG0 = xG0 - delX( 1+MOD(iG0-i+OLx*gridNx,gridNx) ) |
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ENDDO |
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C Find the Y-coordinate of the outer grid-line of the "real" tile |
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yG0 = ygOrigin |
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DO j=1, jG0 |
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yG0 = yG0 + delY(j) |
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ENDDO |
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C Back-step to the outer grid-line of the "halo" region |
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DO j=1, OLy |
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yG0 = yG0 - delY( 1+MOD(jG0-j+OLy*gridNy,gridNy) ) |
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ENDDO |
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|
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C-- Make a local copy of current-tile grid-spacing |
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DO i=0-OLx,sNx+OLx |
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delXloc(i) = delX( 1+MOD(iG0+i-1+OLx*gridNx,gridNx) ) |
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ENDDO |
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DO j=0-OLy,sNy+OLy |
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delYloc(j) = delY( 1+MOD(jG0+j-1+OLy*gridNy,gridNy) ) |
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ENDDO |
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|
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C-- Calculate coordinates of cell corners for N+1 grid-lines |
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DO j=1-OLy,sNy+OLy +1 |
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xGloc(1-OLx,j) = xG0 |
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DO i=1-OLx,sNx+OLx |
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xGloc(i+1,j) = xGloc(i,j) + delXloc(i) |
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ENDDO |
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ENDDO |
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DO i=1-OLx,sNx+OLx +1 |
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yGloc(i,1-OLy) = yG0 |
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DO j=1-OLy,sNy+OLy |
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yGloc(i,j+1) = yGloc(i,j) + delYloc(j) |
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ENDDO |
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ENDDO |
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|
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C-- end bi,bj loops |
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c ENDDO |
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c ENDDO |
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|
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RETURN |
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END |
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