SPTRUNSV

The SPTRUNSV routine spectrally truncates vector fields
             on a global cylindrical grid, returning the fields
             to specific pairs of Polar Stereographic scalar fields.
             The wave-space can be either Triangular or Rhomboidal.
             The grid-space can be either an equally-spaced grid
             (with or without pole points) or a Gaussian grid.
             The grid fields may have general indexing.
             The transforms are all multiprocessed.
             Transform several fields at a time to improve vectorization.
             Subprogram can be called from a multiprocessing environment.

USAGE:    CALL SPTRUNSV(IROMB,MAXWV,IDRTI,IMAXI,JMAXI,KMAX,NPS,
                        IPRIME,ISKIPI,JSKIPI,KSKIPI,KGSKIP,
                        NISKIP,NJSKIP,JCPU,TRUE,XMESH,ORIENT,
                        GRIDUI,GRIDVI,
                        LUV,UN,VN,US,VS,LDZ,DN,ZN,DS,ZS,
                        LPS,PN,SN,PS,SS)

  INPUT ARGUMENTS:
      IROMB    - INTEGER SPECTRAL DOMAIN SHAPE
                 (0 FOR TRIANGULAR, 1 FOR RHOMBOIDAL)
      MAXWV    - INTEGER SPECTRAL TRUNCATION
      IDRTI    - INTEGER INPUT GRID IDENTIFIER
                 (IDRTI=4 FOR GAUSSIAN GRID,
                  IDRTI=0 FOR EQUALLY-SPACED GRID INCLUDING POLES,
                  IDRTI=256 FOR EQUALLY-SPACED GRID EXCLUDING POLES)
      IMAXI    - INTEGER EVEN NUMBER OF INPUT LONGITUDES.
      JMAXI    - INTEGER NUMBER OF INPUT LATITUDES.
      KMAX     - INTEGER NUMBER OF FIELDS TO TRANSFORM.
      NPS      - INTEGER ODD ORDER OF THE POLAR STEREOGRAPHIC GRIDS
      IPRIME   - INTEGER INPUT LONGITUDE INDEX FOR THE PRIME MERIDIAN.
                 (DEFAULTS TO 1 IF IPRIME=0)
                 (OUTPUT LONGITUDE INDEX FOR PRIME MERIDIAN ASSUMED 1.)
      ISKIPI   - INTEGER SKIP NUMBER BETWEEN INPUT LONGITUDES
                 (DEFAULTS TO 1 IF ISKIPI=0)
      JSKIPI   - INTEGER SKIP NUMBER BETWEEN INPUT LATITUDES FROM SOUTH
                 (DEFAULTS TO -IMAXI IF JSKIPI=0)
      KSKIPI   - INTEGER SKIP NUMBER BETWEEN INPUT GRID FIELDS
                 (DEFAULTS TO IMAXI*JMAXI IF KSKIPI=0)
      KGSKIP   - INTEGER SKIP NUMBER BETWEEN GRID FIELDS
                 (DEFAULTS TO NPS*NPS IF KGSKIP=0)
      NISKIP   - INTEGER SKIP NUMBER BETWEEN GRID I-POINTS
                 (DEFAULTS TO 1 IF NISKIP=0)
      NJSKIP   - INTEGER SKIP NUMBER BETWEEN GRID J-POINTS
                 (DEFAULTS TO NPS IF NJSKIP=0)
      JCPU     - INTEGER NUMBER OF CPUS OVER WHICH TO MULTIPROCESS
                 (DEFAULTS TO ENVIRONMENT NCPUS IF JCPU=0)
      TRUE     - REAL LATITUDE AT WHICH PS GRID IS TRUE (USUALLY 60.)
      XMESH    - REAL GRID LENGTH AT TRUE LATITUDE (M)
      ORIENT   - REAL LONGITUDE AT BOTTOM OF NORTHERN PS GRID
                 (SOUTHERN PS GRID WILL HAVE OPPOSITE ORIENTATION.)
      GRIDUI   - REAL (*) INPUT GRID U-WINDS
      GRIDVI   - REAL (*) INPUT GRID V-WINDS
      LUV      - LOGICAL FLAG WHETHER TO RETURN WINDS
      LDZ      - LOGICAL FLAG WHETHER TO RETURN DIVERGENCE AND VORTICITY
      LPS      - LOGICAL FLAG WHETHER TO RETURN POTENTIAL AND STREAMFCN

   Output arguments:
      UN       - REAL (*) NORTHERN PS U-WINDS IF LUV
      VN       - REAL (*) NORTHERN PS V-WINDS IF LUV
      US       - REAL (*) SOUTHERN PS U-WINDS IF LUV
      VS       - REAL (*) SOUTHERN PS V-WINDS IF LUV
      DN       - REAL (*) NORTHERN DIVERGENCES IF LDZ
      ZN       - REAL (*) NORTHERN VORTICITIES IF LDZ
      DS       - REAL (*) SOUTHERN DIVERGENCES IF LDZ
      ZS       - REAL (*) SOUTHERN VORTICITIES IF LDZ
      PN       - REAL (*) NORTHERN POTENTIALS IF LPS
      SN       - REAL (*) NORTHERN STREAMFCNS IF LPS
      PS       - REAL (*) SOUTHERN POTENTIALS IF LPS
      SS       - REAL (*) SOUTHERN STREAMFCNS IF LPS
 
REMARKS: 
        MINIMUM GRID DIMENSIONS FOR UNALIASED TRANSFORMS TO SPECTRAL:

    DIMENSION                    LINEAR              QUADRATIC
    -----------------------      ---------           -------------
    IMAX                         2*MAXWV+2           3*MAXWV/2*2+2
    JMAX (IDRT=4,IROMB=0)        1*MAXWV+1           3*MAXWV/2+1
    JMAX (IDRT=4,IROMB=1)        2*MAXWV+1           5*MAXWV/2+1
    JMAX (IDRT=0,IROMB=0)        2*MAXWV+3           3*MAXWV/2*2+3
    JMAX (IDRT=0,IROMB=1)        4*MAXWV+3           5*MAXWV/2*2+3
    JMAX (IDRT=256,IROMB=0)      2*MAXWV+1           3*MAXWV/2*2+1
    JMAX (IDRT=256,IROMB=1)      4*MAXWV+1           5*MAXWV/2*2+1
 
 


  
SPLIB.tar
  
Library contains routines to be
   be used for a variety of spectral transform functions. (Fortran90) 

   Date posted: 2/23/2007