sptezd.f File Reference

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Functions/Subroutines
subroutine	sptezd (IROMB, MAXWV, IDRT, IMAX, JMAX, WAVE, GRIDMN, GRIDX, GRIDY, IDIR)
	THIS SUBPROGRAM PERFORMS A SPHERICAL TRANSFORM BETWEEN SPECTRAL COEFFICIENTS OF A SCALAR FIELD AND ITS MEAN AND GRADIENT ON A GLOBAL CYLINDRICAL GRID. More...

Detailed Description

Perform a simple gradient spherical transform

Author

IREDELL

Date

96-02-29

Definition in file sptezd.f.

Function/Subroutine Documentation

sptezd()

subroutine sptezd	(		IROMB,
			MAXWV,
			IDRT,
			IMAX,
			JMAX,
		real, dimension(*)	WAVE,
			GRIDMN,
		real, dimension(imax,jmax)	GRIDX,
		real, dimension(imax,jmax)	GRIDY,
			IDIR
	)

THIS SUBPROGRAM PERFORMS A SPHERICAL TRANSFORM BETWEEN SPECTRAL COEFFICIENTS OF A SCALAR FIELD AND ITS MEAN AND GRADIENT 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 FIELS 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 (*) WAVE FIELD IF IDIR>0
[out]	GRIDMN	- REAL GLOBAL MEAN IF IDIR<0
[out]	GRIDX	- REAL (IMAX,JMAX) GRID X-GRADIENTS (E->W,N->S) IF IDIR<0
[out]	GRIDY	- REAL (IMAX,JMAX) GRID Y-GRADIENTS (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:

• SPTRAND PERFORM A GRADIENT 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 49 of file sptezd.f.