SPTRUNS
The SPTRUNS routine spectrally truncates scalar 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 SPTRUNS(IROMB,MAXWV,IDRTI,IMAXI,JMAXI,KMAX,NPS,
IPRIME,ISKIPI,JSKIPI,KSKIPI,KGSKIP,
NISKIP,NJSKIP,JCPU,TRUE,XMESH,ORIENT,
GRIDI,GN,GS)
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.)
GRIDI - REAL (*) INPUT GRID FIELDS
Output arguments:
GN - REAL (*) NORTHERN POLAR STEREOGRAPHIC FIELDS
GS - REAL (*) SOUTHERN POLAR STEREOGRAPHIC FIELDS
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 |