Functions/Subroutines
subroutine	w3ft41 (VLN, GN, PLN, FL, WORK, TRIGS, RCOS)
	SUBPROGRAM: W3FT41 COMPUTES 2.5X2.5 S. More...

Function/Subroutine Documentation

◆ w3ft41()

subroutine w3ft41	(	complex, dimension( 32 , 31 )	VLN,
		real, dimension(145,37)	GN,
		real, dimension( 32, 31, 37 )	PLN,
		complex, dimension( 31 )	FL,
		real, dimension(144)	WORK,
		real, dimension(216)	TRIGS,
		real, dimension(37)	RCOS
	)

SUBPROGRAM: W3FT41 COMPUTES 2.5X2.5 S.

HEMI. GRID VECTOR AUTHOR: R.E.JONES ORG: W323 DATE: 80-11-20

ABSTRACT: COMPUTES 2.5 X 2.5 S. HEMI. GRID OF 145 X 37 POINTS FROM SPECTRAL COEFFICIENTS IN A RHOMBOIDAL 30 RESOLUTION REPRESENTING A VECTOR FIELD.

PROGRAM HISTORY LOG: 93-07-23 R.E.JONES NEW VERSION OF W3FT11, TAKES OUT W3FA12 MAKES PLN 3 DIMENSIONS, PLN IS COMPUTED ONE TIME IN MAIN PROGRAM, TRADES MEMORY FOR MORE SPEED. W3FA12 USED 70% OF CPU TIME.

USAGE: CALL W3FT41(VLN,GN,PLN,FL,WORK,TRIGS,RCOS)

INPUT VARIABLES: NAMES INTERFACE DESCRIPTION OF VARIABLES AND TYPES

VLN ARG LIST 992 COMPLEX COEFF. PLN ARG LIST (32,31,37) REAL SPACE WITH LEGENDRE POLYNOMIALS COMPUTED BY W3FA12. FL ARG LIST 31 COMPLEX SPACE FOR FOURIER COEFF. WORK ARG LIST 144 REAL WORK SPACE FOR SUBR. W3FT12 TRIGS ARG LIST 216 PRECOMPUTED TRIG FUNCS. USED IN W3FT12, COMPUTED BY W3FA13 RCOS ARG LIST 37 RECIPROCAL COSINE LATITUDES OF 2.5 X 2.5 GRID MUST BE COMPUTED BEFORE FIRST CALL TO W3FT11 USING SUBR. W3FA13.

OUTPUT VARIABLES: NAMES INTERFACE DESCRIPTION OF VARIABLES AND TYPES

GN ARG LIST (145,37) GRID VALUES. 5365 POINT GRID IS TYPE 30 OR 1E HEX O.N. 84

SUBPROGRAMS CALLED: NAMES LIBRARY

AIMAG CMPLX REAL SYSTEM W3FT12 W3LIB

WARNING: W3FT11 WAS OPTIMIZED TO RUN IN A SMALL AMOUNT OF MEMORY, IT WAS NOT OPTIMIZED FOR SPEED, 70 PERCENT OF THE TIME WAS USED BY SUBROUTINE W3FA12 COMPUTING THE LEGENDRE POLYNOMIALS. SINCE THE LEGENDRE POLYNOMIALS ARE CONSTANT THEY NEED TO BE COMPUTED ONLY ONCE IN A PROGRAM. BY MOVING W3FA12 TO THE MAIN PROGRAM AND COMPUTING PLN AS A (32,31,37) ARRAY AND CHANGING THIS SUBROUTINE TO USE PLN AS A THREE DIMENSION ARRAY THE RUNNING TIME WAS CUT 70 PERCENT. ADD FOLLOWING CODE TO MAIN PROGRAM TO COMPUTE EPS, PLN, TRIGS, AND RCOS ONE TIME IN PROGRAM.

DOUBLE PRECISION EPS(992)
DOUBLE PRECISION COLRA

REAL             PLN( 32, 31, 37 )
REAL             RCOS(37)
REAL             TRIGS(216)

DATA  PI /3.14159265/

DRAD = 2.5 * PI / 180.0
CALL W3FA11(EPS,30)
CALL W3FA13(TRIGS,RCOS)
DO LAT = 1,37
  COLRA = (LAT - 1) * DRAD
  CALL W3FA12 (PLN(1,1,LAT), COLRA, 30, EPS)
END DO

ATTRIBUTES: LANGUAGE: CRAY CFT77 FORTRAN
MACHINE: CRAY Y-MP8/864, CRAY Y-MP EL2/128

Definition at line 76 of file w3ft41.f.

Functions/Subroutines

Function/Subroutine Documentation

◆ w3ft41()