sptez.f File Reference

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Functions/Subroutines
subroutine	sptez (IROMB, MAXWV, IDRT, IMAX, JMAX, WAVE, GRID, IDIR)
	THIS SUBPROGRAM PERFORMS A SPHERICAL TRANSFORM BETWEEN SPECTRAL COEFFICIENTS OF A SCALAR QUANTITY AND A FIELD ON A GLOBAL CYLINDRICAL GRID. More...

Detailed Description

Perform a simple scalar spherical transform

Author

IREDELL

Date

96-02-29

Definition in file sptez.f.

Function/Subroutine Documentation

sptez()

subroutine sptez	(		IROMB,
			MAXWV,
			IDRT,
			IMAX,
			JMAX,
		real, dimension((maxwv+1)*((iromb+1)*maxwv+2))	WAVE,
		real, dimension(imax,jmax)	GRID,
			IDIR
	)

THIS SUBPROGRAM PERFORMS A SPHERICAL TRANSFORM BETWEEN SPECTRAL COEFFICIENTS OF A SCALAR QUANTITY AND A FIELD ON A GLOBAL CYLINDRICAL GRID.

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 WAVE FIELD IS IN SEQUENTIAL 'IBM ORDER'. THE GRID FIELD IS INDEXED EAST TO WEST, THEN NORTH TO SOUTH. FOR MORE FLEXIBILITY AND EFFICIENCY, CALL SPTRAN. SUBPROGRAM CAN BE CALLED FROM A MULTIPROCESSING ENVIRONMENT.

Parameters

	IROMB	- INTEGER SPECTRAL DOMAIN SHAPE (0 FOR TRIANGULAR, 1 FOR RHOMBOIDAL)
	MAXWV	- INTEGER SPECTRAL TRUNCATION
	IDRT	- INTEGER GRID IDENTIFIER (IDRT=4 FOR GAUSSIAN GRID, IDRT=0 FOR EQUALLY-SPACED GRID INCLUDING POLES, IDRT=256 FOR EQUALLY-SPACED GRID EXCLUDING POLES)
	IMAX	- INTEGER EVEN NUMBER OF LONGITUDES.
	JMAX	- INTEGER NUMBER OF LATITUDES.
[out]	WAVE	- REAL (2*MX) WAVE FIELD IF IDIR>0 WHERE MX=(MAXWV+1)*((IROMB+1)*MAXWV+2)/2
[out]	GRID	- REAL (IMAX,JMAX) GRID FIELD (E->W,N->S) IF IDIR<0
	IDIR	- INTEGER TRANSFORM FLAG (IDIR>0 FOR WAVE TO GRID, IDIR<0 FOR GRID TO WAVE)

SUBPROGRAMS CALLED:

• SPTRANF PERFORM A SCALAR SPHERICAL TRANSFORM
• NCPUS GETS ENVIRONMENT NUMBER OF CPUS

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

Definition at line 47 of file sptez.f.